General Aviation Airworthiness Alerts

wrinkles In the fuel c e l l . Holding the aircraft t a l l section to the ground and p h y s i c a l l y shaking the a i r c r a f t 1s the best method for dislodging the water. Then drain all the sumps, taking special precautions to drain at least 1 quart from the main fuel sump on the firewall. The submitter recommends t h i s procedure be followed after the aircraft has been exposed to rain or snow or a f t e r any long p e r i o d s of storage. Cessna Alternator Bracket The alternator was found loose on i t s mounting Model R182 P/N 76906 during an Inspection. Further investigation revealed the mount boltholes had e l o n g a t e d . Aircraft time - 205 hours. Cessna Alternator Cooling The alternator cooling fan came apart and cut a Model P210N Fan 4-1nch gash in the battery box. Pieces of the fan also hit a f l e x i b l e fuel hose but did not cut through. Inspection of the fan p i e c e s disclosed fatigue cracks in and around the areas where the blade was formed. The spot welds where the blade assembly was welded to the hub did not f a l l . Aircraft time - 440 hours. Cessna Boot Assemblies The pilot reported the cabin pressure dropped Model P210N P/Ns 1211360-5 and -6 1,600 feet when the gear was extended for approach. Investigation disclosed both boots were cracked and torn next to the bulkhead at the downlock cylinder. There were two reports with aircraft times of 910 and 1,396 hours. Cessna Alternator Through Model T210M Bolts The a i r c r a f t sustained complete a l t e r n a t o r failure during f l i g h t 1n IFR conditions. The p i l o t made an unscheduled landing on battery power without incident. Investigation revealed the alternator through bolts had backed out, and the alternator came apart. A new alternator was o r d e r e d from a s u p p l i e r w i t h s p e c i f i c Instructions that the through bolts be secured with some type of locking device. inspection of the new alternator disclosed no locking device of any kind was used to secure the alternator through b o l t s . The submitter recommends that alternators be checked for some type of positive locking device for the through bolts. 3 Cessna Model T21GN Kinked Cable An Investigation of a gear up landing revealed the warning horn did not sound because of a kink In the control assembly follow-up cable. The kink would not allow full cable travel required to activate the gear warning horn mlcroswltch. Cessna Combustion A1r Model 421C Blower, P/N A-074D48 The ground crew observed dense smoke and fire In the aft area of the nose wheel as the a i r c r a f t taxi ed to the runway. Inspection revealed the smoke and f i r e emitted from the heater exhaust. Further investigation disclosed the combustion a i r motor had f a i l e d and the combustion a i r pressure switch had also f a i l e d in the closed position. The pressure switch controls the Ignltor and fuel supply. Both systems continued to operate. Burning of the excessive r i c h f u e l mixture created the dense smoke and f i r e from the heater exhaust. Cessna Cracked Turnbuckle The primary elevator control cable turnbuckle Model 500 Barrel barrel In the a f t equipment bay was found cracked, l a t e r a l l y , from each threaded end. The submitter recommends a visual Inspection for condition. Aircraft time - 3,525 hours. E K B R A E R Embraer Model 110PX Worn Bearing The pilot advised there was excessive nose wheel shimmy and v i b r a t i o n . Investigation revealed the nose gear c o n n e c t i n g rod bearing was s e v e r e l y worn and had e x c e s s i v e p l a y . Installing a new bearing corrected the shimmy and vibration problem. G A T E S L E A R J E T Gates Learjet Accelerometer The following information Is contained In Gates Learjet Service Mews Letter Mo. 79, dated March 1983: Caution should be taken when performing the 150-hour accelerometer Inspection/check to avoid breaking the coaxial cable/wire when rotating the unit per Instructions, The most common mode of failure experienced 1f a wire Is broken Is lack of pusher. With no p u s h e r , the s t a l l warning system will f a l l the preflight test. Gates Learjet Alcohol Ant1-Ice With the onset of colder weather, operators are All Models System reminded of the Importance of s e r v i c i n g the alcohol ant1-ice system only with methyl alcohol (Methanol), F e d e r a l S p e c i f i c a t i o n O-M-232 Grade A, as stated 1n the maintenance and flight manuals. This 1s the only alcohol approved for this system. 4 G U L F S T R E A M A E R O S P A C E Gulfstream Model 500U Rod and End Assembly, P/N 5610252-39 One engine experienced a power Toss during takeoff. The engine Intake air was shut off due to separation of the b u t t e r f l y valve linkage. The ball and socket of the rod and end assembly separated from the alternate air butterfly valve actuating arm. The weight of the arm that remained attached to the lower butterfly valve arm caused the lower butterfly valve to c l o s e , shutting off intake air to the engine. Gulfstream Models 690A and 690B Drag Link Support Structure A mechanic found three separate a i r c r a f t with cracks along the lower forward section of the channel, P/N 310054-42. The cracks were at the channel attachment to the right side of the f u s e l a g e nose s t r u c t u r e . The s u b m i t t e r recommends careful attention be given this area during inspection. Gulf stream Model 690D Chafed Torque Tube Elevator torque tube damage has been reported on low time aircraft. Damage occurs from rubbing on a hydraulic line mount bracket. The bracket 1s used to support the hydraulic brake line and Is mounted under the floor beneath the p i l o t ' s seat. The corrective action was to reposition the hydraulic l i n e bracket and r e p l a c e the damaged torque tube. H U G H E S Hughes Blower Drive Belt The p i l o t observed a burning rubber odor and Model 369D P/N 369D25623 (approximately 2 minutes later) a high frequency v i b r a t i o n developed. The Inner cord of the blower drive belt separated and was drawn Into the blower, causing the shaft to shear. The mechanic believes the belt became loose (or stretched) and rode up on the bracket, causing the failure. The b e l t had been Installed and shimmed to maximum tension 47 hours previously. The submitter recommends the b e l t again be shimmed to maximum tension 25 hours after a new installation. Hughes Rod End Bearing The p i l o t observed vibrations from the t a l l Model 369D Failure rotor during forward f l i g h t . He was aware of holding a 3-Inch deflection forward of neutral on the l e f t pedal In order to continue straight f l i g h t . An emergency was declared and a safe l a n d i n g was a c c o m p l i s h e d . I n v e s t i g a t i o n revealed the rod end bearing on one of the t a l l rotor pitch change l i n k s had f a i l e d . T h i s failure allowed the pitch link to s h i f t to the retaining bolt and nut assembly. The retaining bolt and nut assembly prevented complete loss of t a l l rotor control. The submitter advised the failed rod end appeared normal during a 100-hour Inspection the previous day. Part total time - 500 hours. The person who admits he has a lot to learn has already learned a lot. 5 I S R A E L A I R C R A F T Israel Nose Wheel Four of the seven strands of a 7x19 cable were Model 1124 Steering Cable found broken at Station 19.683. The submitter P/N 503028-535 advised the broken strands were on the outside of the p u l l e y between the p u l l e y and the bulkhead, and the area 1s d i f f i c u l t to Inspect. The area had been Inspected 180 hours prior to finding the broken cable strands. The submitter recommends that 1124 operators be aware of close Inspections required 1n this area. M 0 0 N E Y Mooney Rusted Longeron Model M20C The l e f t lower longeron was found rusted from the Inside out in several p l a c e s . This was the second rusted longeron the submitting repair s t a t i o n has r e c e n t l y found. Mooney Service B u l l e t i n M20-208 pertains to the problem. Problem Area Left and Right P I P E R Piper Nose Steering Model PA-24 Bell crank The nose gear steering bell crank Indicated e x c e s s i v e wear on t h e cam f a c e s . Investigation disclosed peenlng r e s u l t i n g from excessive c l e a r a n c e between the steering bellcrank and the steering arm bushings. Both steering arm bushings were worn to hourglass shapes, and one showed indications of not turning. The submitter advised this condition could be prevented by maintaining gap clearances between the bushings and bellcrank 1n accordance with P i p e r C o m a n c h e S e r v i c e M a n u a l , Chapter 6-16{a). The s u b m i t t e r a l s o advised these parts are common to PA-30 and PA-39 aircraft. Piper Flap Actuator The actuator worm shaft came out of the flex Model PA-31 P/N 451 813 shaft gearbox and the flap dropped down during landing r o l l o u t . Disassembly of the f l a p actuator assembly r e v e a l e d the worm shaft retaining nut had an Improperly staked lock tab washer. This allowed the worm retaining nut to run loose on the threads. The threads were eventually worn to the p o i n t t h a t the nut slipped off over the threads. A i r c r a f t time, 1,253 hours. 6 Piper Deteriorated Hose The p i l o t advised of low pneumatic pressure. Model PA-31-300 Investigation disclosed the hose coupling In front of the regulator assembly had deteriorated and one side had blown o u t . The submitter a d v i s e s the hose was o r i g i n a l equipment. Aircraft time - 1,966 hours. Piper Gear Door The main gear t i r e s can contact the gear door Model PA-31-325 Actuator Hoses actuator hoses upon retraction. The submitter advised of one Incident where the t i r e struck the hose and broke the f i t t i n g off the actuator, which resulted 1n loss of hydraulic fluid and an emergency landing. The hoses can be secured to other s o l i d l i n e s In the wheel well and the actuator f i t t i n g s r o t a t e d to provide more clearance. The submitter suggests the hoses and fittings be checked during gear retraction with the aircraft on jacks to be positive of adequate clearance. Piper Sheared Bearing Model PA-31-350 Retainer Pins A torque l i n k broke d u r i n g t a k e o f f . Disassembly of the right main gear strut assembly revealed that three of the pins had sheared and one was missing. T h i s allowed the piston to extend and be held only by the torque links until one broke. Piper Pltot Head The pltot head would not f u l l y heat and froze Model PA-34-200T over. The reporting repair station advised this was the f i f t h p l t o t head replaced within the past 6 months on low-time Piper aircraft because of the same problem. Time on reported a i r c r a f t - 149 hours. Piper Model PA-36-300 Cracked Fittings The l e f t and r i g h t f o r w a r d s p a r fuselage-to-wing attach f i t t i n g s were found cracked. This area was Inspected because the pilot reported he could hear a "thump" sound on landing. Piper Carburetor Heat Both carburetor heat boxes were found cracked Model PA-44-180 and the a i r v a l v e s h a f t s were found worn severely during an annual Inspection. A i r c r a f t time - 738 hours. 7 Piper Model PA-60-601P Corroded Pushrods The aileron pushrods were found corroded. There were some corroded spots through the tubes. The corrosion was located 51 to 72 Inches from the Inboard end of the tubes 1n the area j u s t a f t of the e n g i n e s . Aircraft time - 1,088 hours. Piper Heater Relay During an Inspection, the heater relay was found Model PA-60-601P separated from the mount bracket. The exposed terminals had s h o r t e d to the h e a t e r . The submitter recommends the terminals on the relay be covered and the wire bundle secured to prevent the relay from f a l l i n g down on the heater. S I A I - M A R C H E T T I SIAI-Marchettl Canopy Latch The manufacturer has determined that the canopy Models F260, F260B tends to 11ft at "Vn eH (velocity never exceed = and F260C 225 knots) which may allow the canopy l a t c h assembly, P/N 2 6 0 - 1 1 - 1 6 4 - 0 1 , to unlock on certain SIAI-Marchettl Models F260, F260B and F260C airplanes. However, the manufacturer has determined that this condition does not involve opening of the canopy. S I A I - M a r c h e t t l has Issued S e r v i c e B u l l e t i n No. 260B29, dated February 20, 1979, which provides Instructions f o r r e p l a c i n g t h e c a n o p y c a t c h , P/N 260-11-129-11, with a longer canopy c a t c h , P/N 260-11-129-13, to prevent accidental unlocking of the canopy. S W E A R I N G E N Swearlngen Corroded Wing Bolts Model SA26-AT During compliance with Airworthiness Directive 81-26-05, the lower forward wing bolts on each wing were found d e f e c t i v e . One b o l t was severely corroded at the shank of the bolt. The other had small white marks In the metal, at the f i l l e t , under the bolthead. Further Inspection disclosed the white marks were Intergranular c o r r o s i o n . The submitter recommends c l o s e a t t e n t i o n be g i v e n t h e s e a r e a s d u r i n g Inspection. Swearlngen Elevator Bracket Model SA226-TC During a routine Inspection, the Inner bearing and bracket on the l e f t elevator were found worn beyond serviceable limits. 8 A C C E S S O R I E S B E N 0 I X Bendlx Distributor Block Magneto P/N 10-52958 Four new d i s t r i b u t o r blocks were found with cracked mounting ears at the screw holes when removed from the boxes. The cracks were cause for rejection In accordance with the overhaul Instructions form L-527-4. M A R V E L - S C H E B L E R Marvel-Schebler Carburetor Model HA-6 Float Pin The engine In a Cessna R182 began losing power while at 3,000 feet a l t i t u d e . Investigation disclosed the carburetor was flooding due to worn float pin bosses. The pin had come out of one boss, preventing the f l o a t needle from properly seating. There was no Indication of the condition prior to power loss. Time on the carburetor - 760 hours. NOTE: A related a r t i c l e appeared In A l e r t s No. 60, dated July 1983. S L I C K Slick Failed Bearing The a i r c r a f t engine was hard to s t a r t . The Magneto P/N M3006 magneto was disassembled and the rear bearing Model 4281R was found frozen and spinning In the bearing housing. E N G I N E S A L L I S O N G A S T U R B I N E O P E R A T I O N S Allison Compressor Mount Assembly Models 250-C28 and -C30 Series Engines Compressor mount assembly, P/N's 6896021, 6898966 and 68998611 have experienced fatigue cracks In areas near the mounting pads. A new compressor mount assembly, P/N 23007217, Is now available through Allison distributors to eliminate fatigue cracks. Allison Commercial Engine Bulletin CEB 72-2085/3085 provides the appropriate service Information for replacement. Allison Commercial Engine Alert Bulletin CEB-A-72-2080/3081 and the appropriate operation and maintenance manual defines Inspection Intervals/criteria for continued airworthiness on e x i s t i n g compressor mount assembly part numbers that are superseded by P/N 23007217. 9 G A R R E T T M A I N T E N A N C E N O T E S DRAIN HOLES Numerous reports, received annually, Identify structural corrosion problems and other types of hazardous conditions that have developed because drain holes in the a i r c r a f t were p a r t i a l l y restricted or completely closed. Many of these reported problems required an appreciable period of time to reach the state of deterioration found. Therefore, It may be assumed the drain holes were also clogged for at least a comparable time Interval. Regardless of materials used to cover an a i r c r a f t , drain holes are necessary to prevent the accumulation of liquids and serve as air vents. To assure the s a t i s f a c t o r y accomplishment of these functions, the manufacturer located these drains in specific locations at the low points of wings, control surfaces, fuel compartments, the fuselage belly, e t c . Should i t be necessary to replace the skin on an aircraft, i t 1s essential that new drain holes be provided at these same locations. Failure to do this creates a suitable environment for future costly problems. Once opened, drain holes require no maintenance other than a periodic check to determine that they have not become clogged. The s k i l l and time involved in doing this would Indeed be a small price to pay for preventing the development of a condition that may not be suspect or detected until too late. NOTE: There was a recent report of plugged drain holes 1n a Cessna 150 a i r c r a f t . The a i r c r a f t had been stripped and repainted sometime p r i o r to finding the drain holes plugged. It Is recommended a thorough inspection of all aircraft openings (pltot s t a t i c , airspeed, drain holes, etc.) be accomplished after aircraft appearance maintenance - cleaning, polish-wax, and painting. B E A W A R E ISOPROPYL ALCOHOL DE1CE SYSTEMS WITH NON-METALLIC LINES IN THE CABIN An in-flight f i r e in the cabin of a DeHavllland DHC-6 airplane was the r e s u l t of f a i l e d tygon plastic (vinyl base) line in the isopropy! alcohol delce Installation. Certain plastic tubing and components become b r i t t l e with service use, depending on how the tubing is secured or terminated, and also on the operating environment. In view of the potential for leakage, the submitter recommends that a l l owners and operators continually monitor the serviceability of the 1n-cab1n components of these systems. 10 C A U T I O N EXPLODING TIRE As the F-14 taxied to the catapult, a troubleshooter noticed that one of the t i r e s showed some abnormal cuts. When he approached the tire assembly to examine the cuts, 1t exploded and caused the following to occur to our (fortunate) victim: The sole and heel of one of the troubleshooter's day-old flight deck boots were p a r t i a l l y blown off. Three hundred f i f t y psl nitrogen escaping from the exploding t i r e Inflated his l e f t trouser leg and then shredded It. He was knocked backwards approximately 5 f e e t , but not seriously Injured due to the protection afforded by the required protective survival f l i g h t deck equipment which he was wearing. More than 900 Incidents of exploding tire/wheel assemblies have been reported during the past 5 years. Although the majority took place during takeoff or landing,' 22 occurred while the aircraft was parked or under tow. An inflated t i r e Is p o t e n t i a l l y far more dangerous than a piece of ordnance because of the difficulty In recognizing an existing problem and the I n a b i l i t y to safe or dearm It. An F-14 malnmount tire will release more than 340,000 pounds of energy while exploding. That's equal to the energy contained 1n half a s t i c k of dynamite, or as much k i n e t i c energy as a 3,000 pound automobile possesses at 58 mpht Avoid the dangers that can result from an exploding t i r e : Insure proper calibration and use of inflation equipment. Identify and replace damaged tire/wheel assemblies. Always follow the established safety procedures contained In the Maintenance Instruction Manual for your particular aircraft when handling tires. Excerpted from U.S. Naval Safety Center Weekly Summary July 10-16, 1983 S O M E T H I N G T O T H I N K A B O U T Special Study; Loss of Control 1n Adverse Weather Accidents The data obtained from the Accident/Incident Data System (AIDS) Indicate the number of loss of control accidents 1n adverse weather has Increased from 67 in 1977 to a peak of 90 1n 1979, decreased to 72 1n 1980, and then Increased to 77 1n 1981. The number of f a t a l i t i e s resulting from these accidents has Increased from 108 In 1977 to a peak of 187 In 1979, then decreased to 157 in 1980, and Increased to 164 1n 1981. The number of estimated hours flown, which was obtained from the General Aviation Activity and Avionics Survey, dated 1981, was 35.8 m i l l i o n 1n 1977, Increased to 43.3 million in 1979, then decreased to 41.0 m i l l i o n In 1980, and further decreased to 40.7 million In 1981. The total number of loss of control accidents 1n adverse weather during the 5-year study period was 387 and the total number of fatalities was 796, resulting In a f a t a l i t y rate of 2.05, which ranks number 1 In fatalities per accident. Of the total number of accidents, 342 (88 percent) were fatal and 291 (75 percent) were in instrument meteorological c o n d i t i o n s . Only 136 (35 percent) of the pilots Involved In these accidents were Instrument rated. Investigation of the data 1n the Enforcement Information System revealed that there were 355 enforcement actions Initiated against pilots for operating In Instrument weather conditions when they did not possess an Instrument rating during the period from 1978 through 1981. Of the 355 enforcement actions Initiated, 253 (71 percent) were concluded with a f i n a l enforcement action 11 against the p i l o t . Loss of control accidents In adverse weather have a direct relation to seasonal weather changes. The high accident periods are In April and November. This study reveals that complex high performance aircraft are more likely to be involved 1n this type of accident. A table of the most Involved a i r c r a f t and accident rates based on a i r c r a f t population 1s included. Of the f i r s t four aircraft with the highest accident r a t i o , three are complex, high performance aircraft. This table i s Included to show the type of a i r c r a f t most Involved 1n these accidents are faster, longer range aircraft, and not to imply that one a i r c r a f t Is any safer than another. AIRCRAFT MOST TNVOLVEO IN THIS TYPE ACCIOENT RANK MAKE AIRCRAFT GROUP NO. ACCIDENTS NO. AIRCRAFT ACCIDENT RATE 1 Beech 36 10 1869 .006 2 Cessna 210 29 6576 .004 3 Gulfstream AA1, AA5 12 2986 .004 4 Beech 35 26 7117 .003 5 Piper PA28 61 23094 .002 6 Mooney M20 12 5990 .002 7 Cessna 172 35 25899 .001 8 Cessna 182 17 14254 .001 9 Cessna 150 22 20682 .001 Information obtained from General Aviation Activity and Avionics Survey (1981), and Census of U.S. C i v i l Aircraft (1981). Adapted from Flight Safety Foundation, Inc., Aviation Mechanics Bulletin (Delta Airlines Tech Review) DANGER - ENGINE INLET SUCTION! One air carrier recently reported an Incident Involving an employee who ventured too close to the inlet of an operating jet engine despite all earlier warnings. In t h i s case, the suction force pulled him toward the inlet. His hat and headphones were Ingested, but, fortunately, he was able to save himself by hooking his elbow around the nose cowl l i p . Damage to the engine exceeded $10,000. This incident, although not f a t a l , serves as a reminder that complacency can be very expensive. Perhaps the lack of awareness of the powerful I n v i s i b l e forces surrounding a dangerous Inlet fosters complacency. All personnel who may be in the area where engines are operated should be aware of the suction forces surrounding an engine Inlet. The accompanying figure Illustrates the typical strength of the pulling force near the Inlet of a wing-mounted jet engine operating near takeoff thrust. The pulling force f e l t over the body 1s the same force f e l t In a strong wind, except that a wind of 25 mph exerts a force of only 20 pounds on an average-size person. By comparison, a force of about 1,000 pounds 1s exerted on a person standing within a step In front of an engine operating at takeoff thrust. Even with an engine at Idle, the pulling force Is greater than 300 pounds. With nothing to hold on t o , a person can offer only about 95 pounds of resistance by skidding on the bottom of his shoes. This means that the pulling force generated by an engine just at Idle Is enough to drag almost anyone Into the spinning compressor and certainly, i t Is enough to pull In loose a r t i c l e s of c l o t h i n g , rags, and loose objects from shirt pockets. The graph also helps to i l l u s t r a t e the deceptive nature of the suction f o r c e . The suction generated by an engine operates in the same manner as the suction generated by a vacuum cleaner. 12 The pulling force Increases rapidly as the distance decreases between the object and the i n l e t . This often tends to foster a false sense of security because very l i t t l e suction may be noticed In the low-velocity area surrounding the Inlet until there Is a substantial force on the body. Then, the suction suddenly doubles with each half step. Merely turning the body 90° from profile could double the force, and standing up from a crouched position could triple the effect. The following are some useful tips to keep In mind while working around operating Jet engines: Not only do the pulling forces Increase rapidly as the object moves toward the i n l e t , but the airflow directions change around the Inlet. A body passing through the d i f f e r e n t airflows Is subjected to twisting effects that could cause tumbling and a loss of body c o n t r o l . This e f f e c t 1s especially strong near the lower H p of the Inlet. The danger area around the Inlet is much larger than that region of p u l l i n g forces shown In the graph. Natural winds and uneven forces from gusts Increase the area of potential danger. Buildings and fences often create strong, highly localized wind forces. The aircraft fuselage and wings can also help create unpredictable wind shears that w i l l add to the inlet-Induced flow f i e l d . Additional margins should always be included for s a f e t y , such as the p o s s i b i l i t y of tripping, slipping, inattention or falling toward the Inlet. Relaxing caution because engines are small or because they are operating at Idle 1s a mistake. Although the airflow of a smaller engine Is less, the suction forces are just as powerful. A l s o , even though operation at high-thrust settings may not be anticipated In ramp areas, the throttles could be advanced with l i t t l e or no warning. Keep a mental picture of the danger areas In mind. There are no procedures requiring personnel to be In such areas during engine operation. Note that the restricted area for the Inlet extends aft of the Inlet opening as well as in front. Wind blown hats or caps or loose a r t i c l e s from s h i r t pockets pose a p a r t i c u l a r l y common and hazardous dilemma — attempting to recover such an article could well r e s u l t in putting you too close to the I n l e t . Avoid this problem by not wearing loose f i t t i n g headwear, c l o t h i n g , raincoats, e t c . , i f you may be In the v i c i n i t y of an operating engine. Do not carry loose articles In shirt pockets. Make sure gloves, scarves and rags are secure. Above a l l , KEEP YOUR DISTANCE!!!! 1000 900 6 Ft 5 Ft 4 Ft 3 Ft 2 Ft 1 Ft DISTANCE FROM INLET NOTICE TO READERS: The General Aviation Airworthiness A l e r t s are, for the most part, prepared from information supplied by those who operate and maintain a i r c r a f t . The FAA encourages the reporting of a l l malfunction or defects that come to the attention of service or operating personnel, even though the problem has been previously reported. FAA Form 8010-4, Malfunction or Defect Report, which supersedes FAA Form 8330-2, Malfunction or Defect Report, Is available from the local General Aviation D i s t r i c t Office and may be used for reporting purposes. 13 " U S GOVERNMENT PRINTING OFFICE • 1963 « l - . 2 1 / < i m > US.Departrnent afTrcnTsportation Federal Aviation Administration Aviation Standards National Field Office P. O. Box 25082 Oklahoma City, Oklahoma 73125 A V N - 1 1 0 Official Business Penalty for Private Use $300 Postage and Fees Paid Federal Aviation Administration DOT 515