AMATEUR-BUILT AIRCRAFT AND ULTRALIGHT FLIGHT TESTING HANDBOOK

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of the FAA 9s continuing efforts to improve the safety record of all types of general avia- tion aircraft, this AC has been revised to include flight testing recommendations for canard-type and ultralight aircraft. 5.DEFINITIONS. The following terms are defined for use in this AC. a.Amateur-built aircraft means an aircraft issued an Experimental Airworthiness Certificate under the provisions of Federal Aviation Regulations (FAR) § 21.191 (g). b.The term ultralight means a vehicle that meets the requirements of FAR § 103.1. c.The term ultralight in this AC also means a two-place training vehicle of 496 pounds or less, operating under an EAA or USUA exemption to FAR Part 103. d.For the purpose of this AC, both an ama- teur-built aircraft and a ultralight vehicle will be referred to as an 8 8aircraft. 9 9 6.DISCUSSION. a.This AC 9s purpose is the following: (1)To make amateur-built/ultralight air- craft pilots aware that test flying an aircraft is a criti- cal undertaking, which should be approached with thorough planning, skill, and common sense. (2)To provide recommendations and suggestions that can be combined with other sources on test flying (e.g., the aircraft plan/kit manufactur- er 9s flight testing instructions, other flight testing data). This will assist the amateur/ultralight owner to develop a detailed flight test plan, tailored for their aircraft and resources. ii AC 90-89A5/24/95 b.The flight test plan is the heart of all profes- sional flight testing. The plan should account for every hour spent in the flight test phase and should be adhered to with the same respect for the unknown that all successful test pilots share. The time allotted for each phase of a personalized flight test plan may vary, and each phase may have more events or checks than suggested in this AC. The goals, how- ever, should be the same. c.The two goals for an amateur builder/ ultralight owner should be as follows: (1)At the end of the aircraft 9s flight test phase, the aircraft will have been adequately tested and found airworthy and safe to operate within its established operational envelope. (2)Incorporation of the flight test oper- ational and performance data into the aircraft 9s flight manual so the pilot can reference the data prior to each flight. 7.REQUEST FOR INFORMATION. a.This AC is designed as a reference docu- ment to assist in preparing a flight test plan for an amateur-built or ultralight aircraft. (1)The suggestions and recommendations in chapters 1 through 6 are for conventionally- designed aircraft with an air-cooled, 4-cycle, recip- rocating engine that develops less than 200 horse- power with a fixed pitch propeller. (2)Chapter 7 deals with flight testing rec- ommendations for canard aircraft. (3)Chapters 8 through 10 address flight testing considerations for ultralight vehicles under FAR Part 103 and two-seat ultralight training vehicles of less than 496 pounds empty weight operating under an exemption to FAR Part 103. b.Because of the large number of existing amateur-built/ultralight aircraft designs and new designs being introduced each year, the FAA encour- ages public participation in updating this document. Send comments, suggestions, or information about this AC to the following address: U.S. Department of Transportation Federal Aviation Administration Flight Standards Service (AFS-340) 800 Independence Ave, SW. Washington, DC 20591 c.Suggestions also may be sent to AFS-340 by FAX (202) 267-5115. d.After a review, appropriate comments, suggestions, and information may be included in the next revision of this AC. 8.TO OBTAIN COPIES OF THIS AC. Order AC 90-89A from: U.S. Department of Transportation Property Use and Storage Section, M-45.3 Washington, DC 20590. William J. White Deputy Director, Flight Standards Service iii 5/24/95AC 90-89A THIS PAGE IS INTENTIONALLY LEFT BLANK, SO THAT THE TOC CAN BE ON PAGE iii PER PLACEMENT IN DOCUMENT. iv 5/24/95 AC 90-89A THIS PAGE IS INTENTIONALLY LEFT BLANK, SO THAT THE TOC CAN BE ON PAGE iii PER PLACEMENT IN DOCUMENT. CONTENTS Page CHAPTER 1.PREPARATION Section 1.Homework............................................................................................................. ..................1 Section 2.Airport Selection.................................................................................................... .................2 Figure 1 - Runway Length Chart................................................................................................. 3 Section 3.Emergency Plans and Equipment........................................................................................ ...4 Section 4.Test Pilot........................................................................................................... ......................6 Section 5.Medical Facts For Pilots............................................................................................. ............7 Section 6.Transporting The Aircraft To the Airport............................................................................. .9 Section 7.Assembly and Airworthiness Inspection................................................................................ 10 Section 8.Weight and Balance................................................................................................... .............14 Figure 2 - Empty Weight CG..................................................................................................... ..15 Figure 3 - Take Off CG......................................................................................................... .......16 Figure 4 - Additional Equipment Added......................................................................................17 Section 9.Paperwork............................................................................................................ ....................18 Section 10.Powerplant Tests.................................................................................................... .................19 Section 11.Additional Engine Tests............................................................................................. ............22 Section 12.Propeller Inspection................................................................................................ ................25 Figure 5 - Propeller Tracking.................................................................................................. .....26 CHAPTER 2.TAXI TESTS Section 1.Low Speed Taxi Tests................................................................................................. ...........29 Section 2.High Speed Taxi Tests................................................................................................ ...........30 CHAPTER 3.THE FIRST FLIGHT Section 1.General.............................................................................................................. ......................33 Section 2.The Role of the Chase Plane.......................................................................................... ........34 Section 3.Emergency Procedures................................................................................................. ...........35 Section 4.First Flight......................................................................................................... ......................36 Section 5.First Flight Procedures.............................................................................................. ..............37 CHAPTER 4.THE FIRST 10 HOURS Section 1.The Second Flight.................................................................................................... ...............41 Section 2.The Third Flight..................................................................................................... .................41 Section 3.Hours 4 through 10................................................................................................... ..............41 CHAPTER 5.EXPANDING THE ENVELOPE Section 1.General.............................................................................................................. ......................45 Section 2.Hours 11 through 20.................................................................................................. .............45 v 5/24/95AC 90-89A Figure 6 - Climb Airspeed and Altitude Graph...........................................................................47 Figure 7 - Best Rate of Climb Speed Graph...............................................................................48 Section 3.Hours 21 through 35: Stability and Control Checks.............................................................49 Figure 8 - Static Stability.................................................................................................... ..........49 Figure 9 - Time................................................................................................................ .............50 Section 4.A Word or Two About Flutter.......................................................................................... .....52 vi 5/24/95 AC 90-89A CONTENTS 4Continued Page Section 5.Spins................................................................................................................ ........................54 Section 6.Accelerated Stalls................................................................................................... .................56 CHAPTER 6.PUTTING IT ALL TOGETHER: 36 HOURS TO 4 4 4? Section 1.Maximum Gross Weight Tests........................................................................................... ....57 Section 2.Service Ceiling Tests................................................................................................ ..............58 Section 3.Navigation, Fuel Consumption, and Night Flying.................................................................59 CHAPTER 7.THOUGHTS ON TESTING CANARD TYPE AMATEUR-BUILT AIRCRAFT Section 1.Canards.............................................................................................................. ......................63 CHAPTER 8.ULTRALIGHT AIRFRAME INSPECTION Section 1.Differences.......................................................................................................... ....................67 Section 2.The Test Pilot....................................................................................................... ...................68 Section 3.Pre-flight Airframe Inspection....................................................................................... .........68 CHAPTER 9.ULTRALIGHT ENGINE/FUEL SYSTEM INSPECTION Section 1.Engine Inspection.................................................................................................... ................71 Section 2.Fuel Systems......................................................................................................... ..................72 CHAPTER 10.ULTRALIGHT TEST FLYING RECOMMENDATIONS Section 1.Three Recommendations................................................................................................ .........75 Section 2.Airport Selection.................................................................................................... .................75 Section 3.Taxiing.............................................................................................................. .......................76 Section 4.First Flight Differences............................................................................................. ..............76 Section 5.Emergency Procedures................................................................................................. ...........77 Appendix 1.Sample Checklist for a Condition Inspection ................................................................. (7 pages)...................................................................................................................... ..................................1 Appendix 2.Addresses for Accident/Incident Information ................................................................. (1 page)....................................................................................................................... ...................................1 Appendix 3.Additional References on Flight Testing ......................................................................... (4 pages)...................................................................................................................... ..................................1 1 5/24/95AC 90-89A CHAPTER 1.PREPARATION 8 8The Laws of Aerodynamics are unforgiving and the ground is hard. 9 9 Michael Collins (1987) SECTION 1.HOMEWORK 8 8If you have no plan--you have no goal. 9 9 Harold Little, Aircraft Manufacturer (1994) 1.OBJECTIVE. A planned approach to flight testing. a.The most important task for an amateur- builder is to develop a comprehensive FLIGHT TEST PLAN. This PLAN should be individually tai- lored to define the aircraft 9s specific level of performance. It is therefore important that the entire flight test plan be developed and completed BEFORE the aircraft 9s first flight. b.The objective of a FLIGHT TEST PLAN is to determine the aircraft 9s controllability through- out all the maneuvers and to detect any hazardous operating characteristics or design features. This data should be used in developing a FLIGHT MANUAL that specifies the aircraft 9s performance and defines its operating envelope. 2 5/24/95 AC 90-89A SECTION 2.AIRPORT SELECTION 8 8An airport should be chosen with the same care and consideration as getting a second doctor 9s opinion. 9 9 Fred Wimberly, EAA Flight Test Advisor (1994) 1.OBJECTIVE. To select an airport to test fly the aircraft. a.The airport should have one runway aligned into the prevailing wind with no obstructions on the approach or departure end. Hard surface run- ways should be in good repair and well maintained to avoid foreign object damage (FOD) to the propel- ler and landing gear. Grass fields should be level with good drainage. Avoid airports in densely popu- lated or developed areas and those with high rates of air traffic. The runway should have the proper markings with a windsock or other wind direction indicator nearby. b.To determine an appropriate runway, use the chart in figure 1 (sea-level elevation), or the fol- lowing rule-of-thumb: c.The ideal runway at sea-level elevation should be at least 4,000 feet long and 100 feet wide. For each 1,000 feet increase in field elevation, add 500 feet to the runway length. If testing a high performance aircraft, the airport 9s runway at sea- level should be more than 6,000 feet long and 150 feet wide to allow a wider margin of safety. Other considerations, such as power to weight ratio, wing design, and density altitude, also should be factored into the equation for picking the best runway for the initial flight testing. 3 5/24/95AC 90-89A Take-off Distance in Feet FIGURE 1.Runway Length Chart d.Identify emergency landing fields located within gliding distance from anywhere in the airport pattern altitude. Since engine failures are second only to pilot error as the major cause of amateur-built aircraft accidents, preparations for this type of emer- gency should be a mandatory part of the FLIGHT TEST PLAN. e.It is advisable to perform flight tests from an airport with an active unicom or tower, even if the aircraft does not have an electrical system or is not equipped with a radio. Even at an uncontrolled field, a communications base should be improvised. For both situations, a hand held radio with aviation frequencies and a headset with a mike and a push- to-talk switch on the stick/yoke is recommended. Good radio communications improves the overall level of safety and reduces cockpit workload. f.The FAA recommends airport selection cri- teria include the availability of hangar space and ramp areas. These facilities will provide protection from inclement weather and vandalism while the air- craft is being tested, maintained, and inspected. g.The airport should have a telephone and fire fighting equipment, the latter being in compli- ance with relevant municipal codes (e.g., fire codes). h.Explain the Flight Test Program and EMERGENCY PLANS to the airport manager or owner. They may be able to assist the amateur- builder in obtaining temporary hangar space, provid- ing ground/air communications, and supplying emer- gency equipment for use during the flight test. 4 5/24/95 AC 90-89A SECTION 3.EMERGENCY PLANS AND EQUIPMENT 8 8The object of the game, gentlemen, is not to cheat death: the object is not to let him play. 9 9 Patrick Poteen, Sgt. U.S. Army 1.OBJECTIVE. To develop a FLIGHT TEST PLAN which contain two sets of emergency plans; one for IN-FLIGHT emergencies and another for GROUND emergencies. a.The IN-FLIGHT emergency plan should address the following: (1)Complete engine failure or partial fail- ure, especially after take off (2)Flight control problems and severe out- of-rig conditions (3)Fire in the engine compartment or cockpit b.The GROUND EMERGENCY plan should be developed to train the ground crew and/or the airport fire department crash crew on the following: (1)The airplane canopy or cabin door latching mechanism (2)The pilot 9s shoulder harness/seat belt release procedure (3)The location and operation of the fuel shut-off valve (4)The master switch and magneto/igni- tion switch location and OFF position (5)Engine cowling removal procedures to gain access to the battery location or for fire fighting (6)The battery location and disconnect procedures (7)Fire extinguisher application and use (8)How to secure the ballistic parachute system c.Ground Crew. Every test of an amateur- built aircraft should be supported by a minimum ground crew of two experienced individuals. The ground crew 9s function is two-fold: 5 5/24/95AC 90-89A (1)To ensure that the aircraft is in air- worthy condition for safe operation (2)To provide assistance to the test pilot in an emergency d.The Airport. (1)If the airport does not have a fire rescue unit, it is suggested the ground crew have a four wheel drive vehicle equipped with a portable radio, first aid kit, metal-cutting tools, and a fire extin- guisher. A minimum of one person should be trained in first-aid. (2)If the airport provides a fire rescue unit, the test pilot should ensure the rescue unit and the ground crew are trained and competent in performing ground emergency functions as identified in the FLIGHT TEST PLAN. (3) Suggestion. For a small donation, some local volunteer fire and rescue companies will provide the amateur-builder with a standby crew dur- ing the initial critical portions of the flight test phase. e.Hospital Location. The ground crew should know the location and telephone numbers of the hos- pitals and fire rescue squads in the vicinity of the airport AND the flight test area. If the test pilot is allergic to specific medications, or has a rare blood type, a medical alert bracelet or card should be car- ried or worn to alert medical personnel of the condi- tion. f.Fire Extinguisher. Fire extinguisher 9s should be available to the ground crew, and a fire extinguisher should be securely mounted in the cock- pit within easy reach of the test pilot. A fire axe, or other tool capable of cutting through the canopy, also should be positioned in the cockpit. g.Fire Protection. There is always danger of a flash fire during test flights. To prevent burns, the pilot should wear an aviation/motorcycle helmet, NOMEX coveralls/gloves and smoke goggles. If NOMEX clothing is not available, cotton or wool clothing will offer some protection from heat and flames. Pilots should never wear nylon or poly- ester clothing because synthetic materials melt when exposed to heat and will stick to the skin. h.Pilot Protection. A modern aviation/motor- cycle helmet, a properly installed shoulder harness, a well designed seat, a clean cockpit design free of protruding components/sharp edges, NOMEX cloth- ing, smoke goggles, and a memorized emergency plan ensure safety during flight testing. i.Parachute. The decision to wear a parachute depends on the type of aircraft being tested. Some aircraft have forward hinged canopies that are not equipped with quick release pins or have pusher propellers which increase the chance of injury to the pilot while exiting the aircraft. Other aircraft designs may pose no exit problems. If the decision is made to wear a parachute, check that it has been recently packed (within 120 days) by a qualified parachute rigger. Ensure that the chute has not been exposed to rain/moisture and when worn, does not interfere with cockpit management. The test pilot should be thoroughly trained on how to exit the aircraft and deploy the parachute. j.Ballistic Chutes. Ballistic chutes are the lat- est development in dealing with in-flight emer- gencies. A ballistic chute is attached to the aircraft and when activated, lowers the whole aircraft and the pilot to the ground at the rate of descent of approximately 20 feet per second. (1)Deployment Scenarios: (i)structural failure (ii)mid-air collision (iii)stall/spin (iv)loss of control/icing (v)engine failure over bad terrain (vi)pilot incapacitation (2)Installation Considerations: The builder should consider the following when installing a ballistic chute: (i)Matching the chute with the air- craft 9s size, weight, and V ne speed (check with the chute manufacturer) (ii)How the chute will be positioned and mounted (iii)The chute 9s effect on the air- craft 9s weight and balance before deployment and aircraft 9s touchdown attitude after deployment (iv)Compatibility of the opening loads and the aircraft 9s structural design limits 6 5/24/95 AC 90-89A (v)The routing of the bridle and harness (vi)The routing of the activating housing (vii)The placement of the activating handle in the cockpit (viii)Incorporation of chute deploy- ment procedures in the in-flight emergency plan and emergency check list (ix)The deployment time, from activation to full chute opening (3)If a ballistic chute is installed, the builder should add the appropriate ballistic chute inspection items to the aircraft 9s pre-flight inspec- tion check list. The builder also should add the ballistic chute manufacturer 9s repack/refitting sched- ule and maintenance inspections to the flight manual and the conditional annual inspection check list. SECTION 4.TEST PILOT 8 8We are looking for a few good Men and Women! 9 9 Marine Corps advertisement (1991) 1.OBJECTIVE. To select a qualified individual to be the test pilot. 2.GENERAL. The test pilot should be com- petent in an aircraft of similar configuration, size, weight, and performance as the aircraft to be tested. If the aircraft 9s builder is the test pilot, the costs involved in maintaining pilot competence should be budgeted with the same level of commitment and priority that is assigned to plans and materials to complete the project. 3.TEST PILOT REQUIREMENTS. a.A test pilot should meet the following mini- mum qualifications: (1)Physically fit: Test flying an aircraft is a stressful and strenuous task (2)No alcohol or drugs in the last 24 hours (3)Rated, current, and competent in the same category and class as the aircraft being tested (4)Current medical and biennial or flight review as appropriate, or a current USUA certifi- cation and flight review b.Suggested Test Pilot Flight Time Require- ments. The following suggested number of flight hours are only an indication of pilot skill, not an indicator of pilot competence. Each test pilot must assess if their level of competence is adequate or if additional flight training is necessary. If an individ- ual determines they are not qualified to flight test an unproven aircraft, someone who is qualified must be found. (1)100 hours solo time before flight test- ing a kit plane or an aircraft built from a time-proven set of plans (2)200 hours solo time before flight test- ing for a 8 8one of a kind 9 9 or a high performance aircraft (3)A minimum of 50 recent takeoffs and landings in a conventional (tail wheel aircraft) if the aircraft to be tested is a tail dragger c.The test pilot should: (1)Be familiar with the airport and the emergency fields in the area (2)Talk with and, if possible, fly with a pilot in the same kind of aircraft to be tested (3)Take additional instruction in similar type certificated aircraft. For example, if the aircraft to be tested is a tail dragger, a Bellanca Citabria or Super Cub is appropriate for training. For testing an aircraft with a short wing span, the Grumman American Yankee or Globe Swift is suitable for training. (4)Be considered competent when they have demonstrated a high level of skill in all planned flight test maneuvers in an aircraft with performance characteristics similar to the test aircraft 7 5/24/95AC 90-89A (5)Study the ground and in-flight emer- gency procedures developed for the aircraft and prac- tice them in aircraft with similar flight characteristics (6)Have logged a minimum of 1 hour of training in recovery from unusual attitudes within 45 days of the first test flight (7)If appropriate, have logged a minimum of 10 tail wheel take-off and landings within the past 30 days (8)Study the performance characteristics of the aircraft to be tested. Refer to the designer 9s or kit manufacturer 9s instructions, articles written by builders of the same make and model aircraft, and study actual or video tape demonstrations of the air- craft. (9)Review the FAA/National Transpor- tation Safety Board (NTSB)/EAA accident reports for the same make and model aircraft to be aware of problems the aircraft has experienced during pre- vious operations (see appendix 2 for the address). (10)Memorize the cockpit flight controls, switches, valves, and instruments. A thorough knowledge of the cockpit will result in controlled and coordinated mental and physical reactions during emergencies. NOTE: The EAA has developed a Flight Advisor Program which offers builders/ pilots assistance in performing a self evalua- tion of the flight test program and/or selec- tion of the test pilot. To obtain additional information, contact a local EAA Chapter or EAA Headquarters, (414) 426-4800. SECTION 5.MEDICAL FACTS FOR PILOTS 8 8If the pilot is unairworthy, so is the airplane! 9 9 Bill Chana, Aeronautical Engineer 1.OBJECTIVE. To identify some of the well known medical causes for aircraft accidents and to stress the importance of a personal pre-flight check- list in addition to an aircraft pre-flight checklist. a.Alcohol. FAR Part 91, 8 8General Operating and Flight Rules, 9 9 § 91.17 requires that 8 hours must elapse from the last drink to the first flight. Test flying an aircraft, however, places additional mental and physical demands on the pilot. The FAA strongly recommends a minimum of 24 hours between the last drink and the test flight. This is because small amounts of alcohol in the blood stream can affect judgement, reaction time, and decrease a pilot 9s tolerance to hypoxia. b.Anesthetics. Local and dental anesthetic can affect a pilots performance in many adverse ways. It is recommended that a minimum of 48 hours elapse from the time of anesthesia to the time the pilot climbs into the cockpit. c.Blood Donations. Do not fly for 3 weeks after donating blood. The body needs approximately three weeks for a complete physiological recovery. Although the physical affects may not be noticeable at sea level, they will become apparent when flying at higher altitudes. d.Carbon Monoxide (CO). CO is a colorless, odorless, tasteless gas that is always present in engine exhaust fumes. Carbon monoxide prevents oxygen absorption by the blood, and exposure to the gas creates vision problems, headaches, disorienta- tion, and blurred thinking (see chapter 1, section 7, paragraph 3 (g) for testing the aircraft for CO contamination). e.Drugs. Similar to alcohol, drugs will reduce or impair judgement and affect reflexes and hand/ eye coordination. It is a given that the use/abuse of illegal drugs is dangerous and against the law. Prescription drugs and over-the-counter remedies, however, also may be dangerous when combined with flying. The FAA recommends all pilots who must take medication consult with an Aviation Medi- cal Examiner (AME) to understand the medication 9s affects on their ability to think and react while in the cockpit. f.Ear and Sinus Pain. (1)Ear and sinus pain is usually caused by the eardrum or sinuses failing to equalize the air pressure during a descent. The blocked ears and sinuses can be caused by a head cold. The pain can be considerable and is most noticeable during 8 5/24/95 AC 90-89A descents. For ear blockages try yawning, swallowing, or chewing gum which may give some relief. The Valsalva procedure can be effective: pinch the nose, close the mouth, and try to force air through the nostrils. (2)If ear blockage occurs during flight, try climbing back to a higher altitude (lower air pres- sure) until the pain lessens. Then begin a gradual rate of descent, allowing the ears and sinuses time to adapt to the increasing pressure. (3)After landing, nasal sprays will give some sinus pain relief. To relieve ear pain, try wet- ting paper towels with hot water, put the towels in the bottom of a plastic or dixie cup and then hold the cups over the ears. The warmth will help ease the inflamed tissues and reduce the pain. If pain continues, see a doctor. NOTE: The best way to avoid this problem is not to fly with a head cold, upper res- piratory infection, or nasal allergic condi- tion. Be advised that some nasal and oral decongestants could be ineffective at altitude and have side effects such as drowsiness that can significantly impair pilot performance. Again, consult with an Aviation Medical Examiner to understand the affects of medi- cation before flying. g.Fatigue. Fly only when healthy, fit, and alert. Mental and physical fatigue will generally slow down a pilot 9s reaction time, affect decision making, and attention span. Lack of sleep is the most common cause of fatigue, but family and business problems can create mental fatigue which can have the same effects on the pilot as lack of sleep. h.Flicker Vertigo. Light, when flashing at a frequency between 4 to 29 cycles per second, can cause a dangerous physiological condition in some people called flicker vertigo. These conditions range from nausea and dizziness to unconsciousness, or even reactions similar to an epileptic fit. When head- ing into the sun, a propeller cutting the light may produce this flashing effect. Avoid flicker vertigo, especially when the engine is throttled back for land- ing. To alleviate this when the propeller is causing the problem, frequently change engine revolutions per minute (rpm). When flying at night and the rotat- ing beacon is creating flicker vertigo, turn it off. i.Underwater Diving. Never fly immediately after SCUBA diving. Always allow 24 hours to elapse before flying as a pilot or a passenger in order to give the body sufficient time to rid itself of exces- sive nitrogen absorbed during diving. j.Stress. Stress from the pressures of a job and everyday living can impair a pilot 9s perform- ance, often in subtle ways. A test pilot may further increase the stress level by setting unreasonable test flying schedules in order to meet an arbitrary 8 8be done by date. 9 9 Stress also may impair judgement, inducing the pilot to take unwarranted risks, such as flying into deteriorating weather conditions or fly- ing when fatigued to meet a self imposed deadline. 9 5/24/95AC 90-89A SECTION 6.TRANSPORTING THE AIRCRAFT TO THE AIRPORT 8 8Best laid plans of mice and men are often stuck in traffic. 9 9 Ben Owen, EAA Executive Director (1994) 1.OBJECTIVE. To reduce damaging the air- craft in transit. The following suggestions may pre- vent this from happening: a.Use a truck or flat bed truck/trailer large enough to accommodate the aircraft and the addi- tional support equipment. b.If the aircraft wings are removable , build padded jigs, cradles, or fixtures to hold and support them during the trip to the airport. c.Secure the fixtures to the truck/trailer , then secure the wings to the fixture. d.Use two or more ropes at each tie down point. e.Use heavy moving pads used for household moves to protect wings and fuselage. Most rent-a- truck firms offer them for rental. f.During the planning stage, obtain applicable permits and follow the local ordinances for transporting an oversized load. Ask the local police if they can provide an escort to the airport. g.Brief the moving crew thoroughly before loading and unloading the aircraft. h.Ensure the designated driver has recent experience driving a truck/trailer and is familiar with the roads to the airport. 10 5/24/95 AC 90-89A SECTION 7.ASSEMBLY AND AIRWORTHINESS INSPECTION 8 8Complacency is one of the major causes of accidents, no matter how well things are going, something can go wrong 9 9 Art Scholl 1.OBJECTIVE. To determine the airworthiness of the aircraft and its systems. 2.GENERAL. a.If the aircraft must be reassembled after being moved to the airport -- take time to do so carefully. This is a critical event because mistakes can easily be made due to the builder 9s preoccupation with the impending first flight of the aircraft. One of the most common and deadly mistakes is to reverse the rigging on the ailerons. To prevent errors in reassembling the aircraft, follow the designer 9s or kit manufacturer 9s instructions, or use a written check list specifically designed as part of the FLIGHT TEST PLAN. At the completion of each major operation, have another expert check the work. b.When the aircraft is reassembled, perform a pre-flight 8 8fitness inspection. 9 9 This inspection should be similar in scope and detail to an annual inspection. The fitness inspection should be accom- plished even if the aircraft has just been issued a special airworthiness certificate by the FAA. Even if a builder was 99 percent perfect and performed 10,000 tasks building the aircraft, there would still be a hundred items that would need to be found and corrected before the first flight. 3.FITNESS INSPECTION - AIRFRAME. The following additional safety check list items may not be applicable to all amateur-built make and model aircraft, but are presented for consideration and review: a.Control stick/wheel: The control stick/ wheel should have a free and smooth operation throughout its full range of travel. There should be no binding or contact with the sides of the fuselage, seat, or instrument panel. There should be no free- play (slack) in the controls, nor should the controls be tight as to have stick-slip movement. 11 5/24/95AC 90-89A b.Rudder pedals: Move the rudder pedals through the full range of travel. The pedal movement should be smooth with no binding. The test pilot should ensure that their shoes will not catch on exposed metal lines, fixtures, or electrical wire har- ness. c.Brakes: Hand and/or toe brake pressure should be firm with no tendency to bleed down or lock up. Spongy brakes that must be 8 8pumped up, 9 9 or show a drop in the level of brake fluid in the reservoir after a few brake applications, indicate a brake fluid or air leak in the system. d.Main landing gear: Ensure that the gear attach points, shimmy dampener, bungees, wheels, brakes, and wheel fairings are airworthy. If applicable, check that the tail wheel pivot point is centered and vertical in relation to the longitudinal axis of the aircraft. It is critical that the main landing gear alignment toe in/toe out is zero or matches the specifications for fuselage/landing gear alignment called out in the plans. Even one landing gear wheel out of alignment can cause a ground loop. e.Control surfaces: Perform rigging checks to ensure that control input for ailerons, rudder, ele- vators, and trim tabs results in the correct amount of travel and direction of the control movement and that contact with the stops is made. Also ensure that the flaps, if installed, have the proper travel, operate as a single unit, and cannot be extended beyond the maximum extended position. It is important to ensure that the control cable tension is correct by checking it with a calibrated tensiometer and confirming that all the attachment hardware is secured and safety- wired. (1)If the cable tension is less than the specifications require, the 8 8in flight 9 9 air loads dur- ing flight will prevent full travel of the control, even if the control has the right amount of deflection and hits all the stops in the cockpit/wing/tail when tested on the ground. With low cable tension, the desired control movement input will be absorbed by the slack in the cables. (2)While checking cable tension, make sure there is no 8 8free play 9 9 in the flight control hinges and rod ends. Free play and loose cable ten- sion combined with control mass imbalance sets the stage for the onset of control surface 8 8flutter. 9 9 Do not, however, rig the controls at too high a cable tension. This will cause high wear rate on the pulleys and prevent good control feel, especially at low air- speeds. f.Instrument panel: All the instruments should be properly secured in the panel and have preliminary markings on them. Airspeed indicator and engine tachometer should be marked with the EXPECTED performance range markings. Oil temperature and oil pressure must have the engine manufacturer 9s recommended operating range marked. If the markings are on the instrument glass face, paint a white slippage mark on both the glass and on the instrument case to alert the pilot in case the glass/range marks have moved. Attach a tem- porary placard to the instrument panel with the expected stall, climb, and glide speeds. It is a handy reference in times of emergency. g.Behind the instrument panel: Very few amateur-built aircraft of the same make and model have the same instrument panel design. Each ama- teur-builder should inspect this area to ensure that all line connections are tight, that nothing interferes with control travel, and there are no loose wires or fuel, oil, or hydraulic leaks. h.Carbon Monoxide: Carbon Monoxide leaks also can be performed. Wait until night or put the aircraft in a dark hangar. Climb into the cockpit and have a friend shine a bright flood light close to the fire-wall. If light leaks into the cockpit, carbon mon- oxide can seep in. Mark it and seal it. i.Engine and propeller controls: All controls should be visually inspected, positive in operation, and securely mounted. The friction lock on both con- trols should be checked for operation. Each control should have full movement with at least a 1 D 4 inch of 8 8cushion 9 9 at the full travel position. The control cables should be firmly attached to the fuselage along each 24 inches of their runs to prevent whipping of the cable and loss of cable movement at the other end. Control cables with ball sockets should have large area washers on either end of the bolt connec- tion. This will ensure the control will remain con- nected, even if the ball socket fails and drops out. j.Static system: The best procedure to check the altimeter for leaks and accuracy is to have the entire static system checked in accordance with FAR Part 43, appendix E, at an FAA-approved repair sta- tion. 12 5/24/95 AC 90-89A 4.FIELD CHECK. Two people are needed to accomplish the following field check that will enable an amateur-builder to detect if the aircraft 9s instrument system is leaking: (Note: This field check is not an accuracy check.) a.Airspeed check: Slip a long rubber hose over the pitot mast (surgical tubing is recommended). As one person reads the airspeed, the other should very slowly roll up the other end of the tubing. This will apply pressure to the instrument. When the air- speed indicator needle reaches the aircraft 9s approxi- mate recommended cruise speed, pinch the hose shut, and hold that reading. The airspeed needle should remain steady for a minute if the system is sound. A fast drop off will indicate a leak in the instrument, fittings, lines, or the test hose attachment. NEVER force air in the pitot tube or orally apply suction on a static vent. This will cause damage to the instruments. b.Altimeter/vertical speed check. (1)To check the static side, apply low suc- tion at the end of the static vent port. The easiest way to gain access to the static system is to remove the static line at the static port. If there are two static ports, tape the unused port closed. Next, get two feet of surgical tubing, seal one end, and tightly roll it up. Attach the open end to the static line and slowly unroll the tubing. This will apply a suction, or low pressure, to the static system. (2)The altimeter should start to show an increase in altitude. The vertical speed indicator also should indicate a rate of climb. The airspeed may show a small positive indication. When the altimeter reads approximately 2,000 feet, stop and pinch off the tube. There will be some initial decrease in alti- tude and the vertical speed will read zero. The altim- eter should then hold the indicated altitude for at least a minute. If altitude is lost, check for leaks. (3) IMPORTANT: The above airspeed and altimeter field checks should not be considered the equivalent of airspeed or static system accuracy tests as certified by a certificated repair station, but a check of the system for possible leaks. These checks do not take into consideration the pitot tube and static ports located on the airframe. The FAA recommends the builder not deviate from the designer 9s original plans when installing the pitot and static system. c.Fuel system: Since 1983, more than 70 per- cent of the engine failures in amateur-built aircraft were caused by fuel system problems. Many times the direct cause of engine failure was dirt and debris in the fuel tank and lines left behind during the manu- facturing process. (1)Before the aircraft 9s fuel tanks are filled, the amateur-builder should vacuum any manu- facturing debris from each tank and wipe them down with a 8 8tack 9 9 cloth (available from a paint supply store). Next, the system should be flushed with avia- tion grade gasoline several times in order to remove any small or hard to reach debris from the tanks and lines. The fuel filter/gasolator screen/carburetor finger screen should also be cleaned. The amount of time spent 8 8sanitizing 9 9 the fuel system will pro- vide big safety dividends for the life of the aircraft. (2)When filling the tanks, place the air- craft in the straight and level cruise position. Add fuel in measured amounts to calibrate the fuel tank indicators. While allowing the aircraft to sit for a short time to observe for possible leaks, inspect the fuel tank vents to see if they are open and clear. Check that the fuel tank caps seal properly. If there are no leaks and the fuel system has an electric boost pump, pressurize the system and again check for leaks. The fuel selector, vents and fuel drains should be properly marked and tested for proper operation. NOTE: Many amateur-built aircraft take 5 to 8 years to build. During that time, many rubber-based oil and fuel lines and cork gas- kets that were installed early in the building process may have age hardened, cracked, and/or turned brittle. The builder should carefully inspect these components and replace as necessary to prevent a premature engine failure. d.Hydraulic system: The hydraulic system should function dependably and positively in accord- ance with the designer 9s intent. Retractable landing gear should be rigorously cycled on the ground, using both the normal and emergency landing gear extension system. e.Safety belt and shoulder harness: These items should be checked for condition and proper installation. A review of amateur-built aircraft accidents has disclosed a significant number of accidents in which the seat belt mounting hard points 13 5/24/95AC 90-89A failed. Each seat belt and shoulder harness mounting hard point should be built to the designer 9s specifica- tions to ensure that it will hold the harness and pilot in the aircraft at the ultimate design 8 8G 9 9 load speci- fication, both positive and negative, for the aircraft. f.Avionics and electrical checks: Test the avi- onics systems. Perform an operational check to ensure the radio(s) transmit and receive on all fre- quencies. Inspect circuit breakers/fuses, micro- phones, and antennas for security and operation. Test the ELT for proper operation and battery life. Elec- trical systems can be checked for operation of lights, instruments, and basic nav/comm performance. Other electrical systems, such as generator/alternator output can be checked during the engine run-ins, taxi, and flight tests. Check the battery and the battery compartment for security and if applicable, ensure that the battery is properly vented to the outside of the aircraft. Check the condition of the engine to airframe bonding (grounding) wire. Ensure that all electrical instruments operate properly. g.Cowling and panel checks: Ensure that all inspection panels are in place, the cowling is secured, and cowl flap operation is satisfactory. Inspect the propeller spinner and its backing plate for cracks. h.Canopy/door locks checks: Ensure the can- opy or doors on the aircraft work as advertised. Dou- ble check the canopy or door lock(s) so the canopy and doors will not open in flight and disturb the airflow over the wings and stall the aircraft. If a canopy jettison system is installed, check for proper operation when the aircraft on the ground and when it is on jacks. (Jacks will simulate flight loads on the aircraft.) 14 5/24/95 AC 90-89A SECTION 8.WEIGHT AND BALANCE 8 8Never argue with your spouse or a mathematician 9 9 Phil Larsh, Accident Prevention Counselor, Colfax IN (1994) 1.OBJECTIVE. To discuss the importance of developing an accurate weight and balance calcula- tions for both test and recreational flights. Additional information on weight and balance can be found in AC 91-23A, Pilot 9s Weight and Balance Handbook. a.A good weight and balance calculation is the keystone of flight testing. Accurately determining the aircraft 9s take-off weight and ensuring that the center of gravity (CG) is within the aircraft 9s design for each flight is critical to conducting a safe flight test. b.An aircraft should be level when weighed, spanwise and fore and aft in accordance with the manufacturer 9s instructions, and should be in the level flight position. It is highly recommended that the weighing be done in an enclosed area, using three calibrated scales. Bathroom scales are not rec- ommended because they are not always accurate. 15 5/24/95AC 90-89A ITEMSWEIGHT(LBS)ARM(INCHES)MOMENT(IN-LBS) LeftWheel RightWheel TailWheel TOTALS 101 99 42 242 60 60 180 80.8 6060 5940 7560 19560 TOTALMOMENT=EmptyweightCGor19560=80.8 TOTALWEIGHT 242 FIGURE 2.EMPTY WEIGHT CG 2.DETERMINING EMPTY WEIGHT CG. a.The sample airplane for determining empty weight is a single seater, which the kit manufactur- er 9s design empty weight of 253 pounds and a gross weight limit of 500 pounds. The datum line is located at the nose of the aircraft and the CG range is between 69 to 74 inches from the datum. b.To work a CG problem, figure the EMPTY WEIGHT CG first. On a piece of paper draw four blocks. Title each block from left to right as shown in figure 3. (1)Under the block titled item, vertically list 8 8left wheel, 9 9 8 8right wheel, 9 9 and 8 8nose/tail wheel. 9 9 (2)Place a calibrated scale under each wheel and record the weight on each gear, in pounds, in the weight block along side the appropriate wheel. This process is done with an empty fuel tank. (3)Measure in inches the distance from the datum line, or imaginary point identified by the manufacturer (e.g., nose of the aircraft), to the center line (C/L) of the three wheels. Record the distance of each wheel and place it in the moment arm block beside the appropriate wheel (see figure 2). (4)Multiply the number of inches (arm) by the weight on each wheel to get the moment (inch- pounds) for each wheel. Add the weight on the three gears and the three moments in inch pounds and divide the total weight into the total moment. The sum is the 8 8EMPTY WEIGHT CENTER OF GRAVITY 9 9 in inches. In the sample case, the empty weight CG is 80.8. NOTE: All calculations should be carried out to two decimal places. 16 5/24/95 AC 90-89A ITEMSWEIGHT(LBS)ARM(INCHES)MOMENT(IN-LBS) A/C Pilot Fuel TOTALS 242 170 30 442 80.8 65 70 74 19560 11050 2100 32710 TOTALMOMENT=TakeoffCGor32710=74 TOTALWEIGHT 442 FIGURE 3.TAKE-OFF CG 3.DETERMINING TAKE-OFF WEIGHT CG. a.Since the aircraft 9s empty weight and empty weight CG are fixed numbers, the only way an air- craft 9s CG can be changed is by adding weight in other locations. b.For example, in figure 3, the aircraft 9s empty weight has been written in the appropriate blocks. The pilot weighs 170 pounds and fuel (5 gal- lons) weighs 30 pounds. c.Again, all measurements are made from the datum to the center line of the object that has been added. Weight multiplied by inches from the datum equals moment. Add the weights and moments to find the take-off CG for that particular flight. d.Loaded in this configuration, the aircraft is within the CG flight envelope and is safe to fly. 17 5/24/95AC 90-89A ITEMSWEIGHT(LBS)ARM(INCHES)MOMENT(IN-LBS) A/C S/B Pilot Strobe Fuel Fuel TOTALS 242 15 170 1.5 30 1.5 460 80.8 75 65 179 70 55 74.3 19560 1125 11050 268.5 2100 82.5 34186 TOTALMOMENT=AlterationTakeoffWeightCGor34186=74.3 TOTALWEIGHT 460 FIGURE 4.ADDITIONAL EQUIPMENT ADDED 4.ADDING ADDITIONAL EQUIPMENT. a.During flight testing, a strobe battery and hand held radio are added. The battery/battery box weight is 15 pounds and the location is 75 inches aft of the datum; the strobe assembly weight is 1.5 pounds and is located 179 inches aft of the datum; the radio 9s weight is 1.5 pounds and is located 55 inches aft of the datum (see figure 4). b.In the sample problem, the previous figures for take-off weight and moment are still accurate, hence those numbers have been listed in the appro- priate blocks. (1)Add the battery, strobe, and radio num- bers in the appropriate locations and calculate the totals. At 465 pounds, the aircraft is still 35 pounds under its design gross weight limit of 500 pounds but is out of balance because the CG has moved .3 inches further aft (74.3 inches) than the allowable rear CG limit of 74 inches. (2)Since the aircraft is out of balance with an aft CG, it is no longer 100 percent stable in pitch and would be dangerous to fly. In most cases, it is not the amount of weight added to the aircraft that can cause a major safety problem but its loca- tion. (3)To bring this aircraft back into the safe CG range, the battery would have to be moved 9 inches forward (66 inches from the datum line). Another alternative is to install 8 pounds of ballast in the nose (20 inches from the datum). (4)If the sample aircraft exceeded the designer 9s gross weight limit (e.g., 300 pound pilot) instead of the CG limit, its climb, stall, and perform- ance capability would be poor and the possibility for in-flight structural failure would be high. NOTE: In the sample weight and balance, positive numbers were chosen by placing the datum line on the nose of the aircraft. Some manufacturers prefer to use a datum located somewhere between the aircraft 9s nose and the leading edge of the wing. (5)This kind of datum will set up a system of positive arms (items located aft of the datum) and negative arms (items located forward of the datum). (6)When working a weight and balance problem with negative and positive moments, sub- tract the sum of all negative moments from the sum of all positive moments to reach a 8 8total moment 9 9 for the aircraft. 18 5/24/95 AC 90-89A SECTION 9.PAPERWORK 8 8It is harder to write a lie in a logbook than tell one, because your eyes see it and your fingers feel it. 9 9 Bob Moorman, Ultralight Instructor (1994) 1.OBJECTIVE. To have the proper documenta- tion and paperwork to conduct the flight test. a.Weight and Balance: The weight and bal- ance for the aircraft should be carefully done. The gross weight and CG range should be determined prior to every flight. b.Airworthiness/Registration/Operating Limitations/Placards/Weight and Balance: Must be on board, or the aircraft is not legal to be operated. c.Checklists: In addition to the assembly/air- worthiness checklist previously discussed in section 7, the builder should prepare the following check- lists: preflight; take-off/cruise; before starting; descent/before landing; starting the engine; after landing; before takeoff; securing the aircraft; and emergency procedures. A checklist to cover the above procedures may seem a tedious task, but it will only be the size of a 5x8 card -- similar to a checklist for a Cessna 150 or a Piper PA-28-140. NOTE: The amateur-builder should antici- pate several revisions to the checklists. d.Flight Manual: It is imperative a flight manual describing the anticipated performance of the aircraft be written by the aircraft builder/kit manufac- turer. The manual will be revised several times dur- ing the flight test phase until it accurately reports the aircraft 9s performance. e.Maintenance Records (logbooks): Opera- tors of amateur-built aircraft are required to only record the yearly condition inspections in accordance with the aircraft 9s operating limitations. The FAA recommends, however, that every amateur-built air- craft/ultralight owner record in the aircraft 9s logbooks all inspections and maintenance performed. This will create an aircraft 9s maintenance history and will be invaluable in spotting trends. 19 5/24/95AC 90-89A SECTION 10.POWERPLANT TESTS 8 8Don 9t short-change the engine tests or you won 9t be around to give your grandkids a ride. 9 9 Dick Koehler, A&P Instructor (1994) 1.OBJECTIVE. To ensure that the engine has been properly run-in and is safe to operate in all rpm ranges. a.An engine pre-oil and cold compression test can be conducted as follows: (1)Remove the rocker-box covers and one spark plug from each cylinder. (2)Using an external oil pump, or by rotat- ing the propeller in the direction of rotation, pump a substantial supply of oil up from the sump into the rocker arms. (3)When the engine is pre-oiled, run a cold compression test of each cylinder. (4)The results will serve only as an initial bench mark for comparing other compression tests taken after the engine has been run-up to operating temperature. b.New/newly overhauled engine run-in proce- dures: (1)Most amateur-builders start with a new or newly overhauled engine and proceed to 8 8run it in 9 9 on the airframe. This practice is followed due to lack of access to a test cell or a special 8 8club 9 9 propeller that is specifically designed to aid in engine cooling during run-in. There are pros and cons to using an airframe to run in an engine, but the best advice has always been to follow the engine manu- facturer 9s instructions. These instructions are found either in the manufacturer 9s overhaul manuals, serv- ice bulletins, or service letters. Following the manu- facturer 9s instructions is especially important if the engine has chrome cylinders which require special run-in procedures. (2)Also, before running-up the engine, be certain that it has the proper grade oil in the sump. Some new and newly overhauled engines are shipped with a special preservative oil to prevent corrosion. 20 5/24/95 AC 90-89A Drain this out and reservice the engine with the cor- rect oil before starting. c.Used engine run-in procedures: Some ama- teur-builders install a used engine from a flyable air- craft. The same checks and adjustments used on a new or newly overhauled engine should be con- ducted. New and used engines require special attention to engine cylinder baffling to ensure cyl- inder cooling is within the engine manufacturer 9s cylinder head temperature specifications. d.Pre run-in checks: (1)Before beginning the powerplant tests, inspect the engine and propeller carefully. All fuel and oil line connections should be tight. Check the torque on the engine mount attaching bolts. Be cer- tain that there are no tools, hardware, or rags laying between the cylinders or under the magnetos. (2)Check for the proper amount of oil in the engine and that the dip stick gives an accurate reading of the oil quantity. Be advised that some engines were mounted on an angle in type certifi- cated aircraft. These engines have a special part num- ber oil dip stick, which corrects for the different angle of oil in the crankcase. The same engine, mounted level in a amateur-built aircraft with the original dip stick, will not show the correct oil quan- tity. e.Test and Support Equipment: (1)A cylinder head temperature gauge (CHT) is needed to ensure that all cylinders are receiving the proper flow of cooling air. (2)On the newer aircraft engines, the cyl- inders are drilled and tapped to accept a bayonet type of CHT thermocouple probes. For older engines, the thermocouple is designed like a spark plug washer and fits under a spark plug. It can be installed in any cylinder, either under the top or bottom spark plug. (3)Each type of CHT design can have multiple thermocouples which are connected to a selector switch in the cockpit. The pilot then selects the cylinder he wants to monitor. This also is an excellent troubleshooting tool for identifying fouled plugs and bad ignition leads. (4)If there is only one CHT thermocouple, attach it to the rearmost cylinder on the right side of the engine (as viewed from the cockpit) and run- up the engine. Run the same test on the opposite rearmost cylinder to be certain the hottest running cylinder was selected. Calibrated oil pressure and oil temperature gauges also are needed to test the accuracy of the engine instruments installed in the aircraft. (5)The following support equipment is needed: 50 feet or more of tie-down rope, tie-down stakes, two chocks for each wheel, fire extinguisher, assorted hand tools, safety-wire, cotter-pins, ear and eye protection, grease pencils, logbooks, clip board, pen and paper, a watch to time the tests, rags, and manufacturer 9s instructions. f.Safety Precautions: Before the first engine run, ensure the aircraft is tied down, brakes on, and the wheels are chocked. The builder and flight test team should wear ear and eye protection. All flight test participants should be checked out on fire extin- guisher use and operation. During engine runs, do not allow anyone to stand beside the engine, or in- line or close to the propeller. Making minor adjust- ments to a running engine, such as idle and mixture settings, is a very dangerous procedure and should be done with great care by experienced individuals. g.The First Engine Run: (1)The first start of the engine is always a critical operation. The engine should be pre-oiled in accordance with the manufacturer 9s instructions. For aircraft using other than FAA-approved oil pres- sure and temperature gauges, the FAA recommends attaching an external calibrated oil temperature and pressure gauge to the 4 cycle engine in order to cali- brate the engine instruments. After priming the engine and completing the starting engine checklist items, the first concern is to get an oil pressure read- ing within the first 20 to 30 seconds. If there is no oil pressure reading -- shut down. (2)There are three common problems that would cause low or fluctuating oil pressure. (i)Air in the oil pressure gauge line: This is easily fixed by loosening the line connection near the oil pressure gauge and squirting oil into the line until full. Another option is to use a pre- oiler to provide the pressure and carefully bleed the air out of the line near the oil gauge by loosening the B-nut that connects the oil line to the gauge. 21 5/24/95AC 90-89A (ii)A misadjusted oil pressure relief valve: Cleaning the pressure relief ball, checking for the proper number of washers, correcting spring ten- sion, and re-adjusting the setting could solve the problem. (iii)An internal problem within the engine (most likely the oil pump): An engine tear down would be required. (3)With good oil pressure/temperature readings and the engine running smoothly, ensure that the engine oil pressure and temperature gauges in the cockpit match the calibrated oil pressure and temperature gauges, which were attached to the air- craft for the first run. Do not overlook this test. It is critical to determine the accuracy of the cockpit engine gauges not only for the ground engine run- in period, but for in-flight engine cooling tests. (4)Work through the engine manufactur- er 9s run-in schedule. The majority of the engine manufacturers recommend a series of engine runs from low rpm to maximum rpm. Each run usually incorporates a 200 rpm increase and lasts no longer than 10 minutes. The secret to a successful engine run is not to let the engine temperatures exceed manufacture 9s limits during engine runs. NOTE: Engines with chrome cylinders or chrome rings require different high power run-in programs. Follow the manufacturer 9s run-in instructions to ensure the engine will perform satisfactorily over its lifetime. h.Engine Cool Down: After a ground-run, the cooling off period takes approximately an hour. This is because a newly overhauled engine needs time for the internal parts (e.g., rings, cylinders, valves, bearings, and gear faces) to expand and contract sev- eral times to obtain a smooth surface that retains its 8 8memory. 9 9 This is a lengthy process even when done right, but it is important not to skip any of the recommended runs to save time. To do so is to risk increasing oil consumption and reducing over- all engine performance, reliability, and engine life span -- which could be costly in the long-term. i.Record the engine run-in data: During the engine run, monitor the cylinder head temperatures, oil temperature, and oil pressure. Record the readings and adjustments for future reference. If the cylinder head temperatures are rising close to the red line, reduce power and stop the test. Some causes of high cylinder head temperatures include using spark plugs with the improper heat range; cylinder head tempera- ture gauges installed on the wrong cylinder; missing or badly designed cylinder head cooling baffles; par- tially plugged fuel nozzles (applicable to fuel injected engines); fuel lines of improper internal diameter (creates lean mixtures); engine improperly timed either mechanically and/or electrically; and the carburetor fuel mixture set excessively lean. j.After shut-down: (1)After each engine run, check for fuel and oil leaks, loose connections, and hot spots on cylinders (burnt paint). The FAA recommends drain- ing the oil and removing the oil screen/filter within the first 2 hours of running the engine. Check the screen/filter for ferrous metal with a magnet. Wash and inspect the screen/filter for non-ferrous metal like brass, bronze, or aluminum. (2)A very small quantity of metal in the screen is not uncommon in a new or newly over- hauled engine. It is part of the painful process of 8 8running-in. 9 9

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