AC 43-16A

Aviation Maintenance Alerts AC No. 43-16A ALERT NO. 254 SEPTEMBER 1999 Improve Reliability- Interchange Service Experience

A L E R T S

CONTENTS

SPECIAL SAFETY NOTICE, FUEL FILTERS

REPLACEMENT OF VELCON FILTERS ACOXXXXXC CARTRIDGES WITH

ACO-XXXXXK CARTRIDGES1

AIRPLANES

BEECH4

CESSNA6

DIAMOND9

GRUMMAN AMERICAN9

LAKE9

PIPER10

HELICOPTERS

BELL12

ENSTROM14

EUROCOPTER14

MBB14

ROBINSON15

SIKORSKY15

AGRICULTURAL AIRCRAFT

AYRES15

AMATEUR, EXPERIMENTAL, AND SPORT AIRCRAFT

EXTRA15

POWERPLANTS AND PROPELLERS

ALLIED SIGNAL (TEXTRON LYCOMING)16

TELEDYNE CONTINENTAL16

AIR NOTES

SUBSCRIPTION FORM17

IF YOU WANT TO CONTACT US17

**ALERTS E-MAIL ADDRESS UPDATE18

AIRWORTHINESS DIRECTIVES (AD’s) ISSUED IN JULY 199919

GENERAL AVIATION SDR’S FROM JULY 20 TO AUGUST 20, 199920

September 1999 FAA AC 43-16A 1 U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION WASHINGTON, DC 20590

AVIATION MAINTENANCE ALERTS The Aviation Maintenance Alerts provide a common communication channel through which the aviation community can economically interchange service experience and thereby cooperate in the improvement of aeronautical product durability, reliability, and safety. This publication is prepared from information submitted by those who operate and maintain civil aeronautical products. The contents include items that have been reported as significant, but which have not been evaluated fully by the time the material went to press. As additional facts such as cause and corrective action are identified, the data will be published in subsequent issues of the Alerts. This procedure gives Alerts’ readers prompt notice of conditions reported via Malfunction or Defect Reports. Your comments and suggestions for improvement are always welcome. Send to: FAA; ATTN: Designee Standardization Branch (AFS-640); P.O. Box 25082; Oklahoma City, OK 73125-5029.

SPECIAL SAFETY NOTICE,

FUEL FILTERS A situation arose which warrants the immediate attention of all those concerned with aviation safety. We are publishing this notice to make everyone aware of the possibility of aircraft fuel contamination and starvation.

Fuel filters used in fuel farms and fuel delivery vehicles caused this problem. The filter element may deteriorate and create fuel contamination which passes into the aircraft fuel system.

Velcon Filters, Inc., the manufacturer of the suspect filters, came forward in a very professional manner to provide information and help resolve this problem. Velcon Filters, Inc., released the following notice for publication.

REPLACEMENT OF VELCON

FILTERS ACOXXXXXC

CARTRIDGES WITH ACO-XXXXXK

CARTRIDGES BACKGROUND: In the early 1980’s, cartridges were delivered by Velcon Filters which were not only filter elements, removing dirt and other particulate matter, but which also absorbed free (undissolved) water from Jet Fuel and Avgas. The US Navy, Mil-spec (Mil-M-81380C) was revised to acknowledge the water absorbing technology. Some years later, the Institute Of Petroleum (IP) published the “Specifications and Qualification Procedures-Aviation Fuel Filter Monitors With Absorbent Type Elements.” ATA-103 recognizes these IP monitor cartridges as an alternative to API-1581 qualified filter/separators on refueling equipment.

The water absorbing cartridges

(e.g., Velcon’s Aquacon® and CDF® series cartridges) are used primarily as the last series of elements in filter vessels, or converted filter/separator vessels, for aircraft refueling of Jet Fuel and Avgas.

They are sometimes called monitors, fuses, or go-no-go cartridges. They are intended as “insurance” elements, to stop any dirt or water from going into the aircraft with the fuel. The dirt and water capacity is limited, since the primary dirt and water removal function in aviation fuel systems is supposed to occur upstream (tank settling and bottom draw-off, and upstream filter and filter/separator vessels.)

The water absorbing cartridges have standard filter media to remove particulate matter (dirt), and also contain the water

FAA AC 43-16A September 1999 2 absorbing media (similar to the media in baby diapers, incontinence pads, etc.)

which will absorb free (undissolved) water from the fuel. The free water is removed to levels normally down to 2 PPM or less. At standard flow rates, 50% or higher of the elements’ rated flow, the differential pressure will rise across the cartridge as water is accumulated. The cartridges are changed at 15 psid differential pressure.

A large amount of free water in the fuel (slug) will rapidly increase the differential pressure, shutting off the fuel flow as the water is absorbed. An undetermined number of cartridges have plugged in normal operation, preventing unexpected water slugs from getting into aircraft.

FIELD INCIDENTS: There was an incident in 1998 in San Diego, California where some helicopters were observed to have some gelatinous appearing media in the fuel controls. This was determined to be the same polymer material contained in the Velcon upstream ACO-XXXXXC water absorbing cartridges on the fuel truck.

Velcon began testing at various flow rates and water quantities in the fuel in their Colorado Springs laboratory. It was found that at low flow rates (continually less than 50% of the element’s rated flow) and at low water add rates (less than 50 PPM) the water absorbing media would continually absorb the water, but the observed differential pressure would not rise. With continued low levels of water at low flow rates, the media continued to absorb water until eventually the media was extruded through the media migration barrier in the element and flowed downstream.

Velcon tested all their series of water absorbing cartridges (ACO-XXXXXC, ACI-XXXXXC, and CDF-2XXK). It was found that the ACO-XXXXXC series cartridges were the only series that had the low flow, low water problem with media extrusion. Velcon revised the Operating Procedures to caution against operating at less than 50% rated flow.

Following suggestions by airline companies and other operators that the flow restrictions would be too difficult to follow, Velcon accelerated testing of the ACO cartridges with a water absorbing media which was not adversely affected by the low flow, low water extrusion problem.

(The ACO-6XX01C cartridges had been fully qualified to the original IP Monitor Specification, which reflected state-of-the-art filter technology.)

The ACO-XXXXXK cartridges were finally developed in May of 1999. Testing to the IP Monitor Specification, with additional low flow, low water tests, were performed in May 1999. This testing was witnessed by representatives from the IP. The IP Monitor Specification has recently been revised to include the low flow, low water tests based on the unanticipated operational procedures related to the 1998 incident.

An announcement was made to all customers and Velcon distributors on May 28, 1999, that Velcon would replace all ACO-XXXXXC cartridges in stock or in service with the ACO-XXXXXK cartridges, free of charge. Velcon sent out a notice to their distributors on June 14, 1999, enclosing a copy of the “Product Recall

September 1999 FAA AC 43-16A 3 Card” which had been sent to all distributors/customers that had received ACO-XXXXXC cartridges directly from Velcon. Information on this exchange of cartridges was also included in the June 1999 issue of the Velcon Clarifier, and was also added to the Velcon Internet information (www.velcon.com) Velcon was informed of an incident at Vero Beach, Florida in mid-July 1999 where the gelatinous material was found during normal fuel draining in a Piper Archer. This was brought to the attention of the Orlando, Florida Flight Standards District Office (FSDO) by the aircraft pilot.

Upon contact with Velcon, it was recommended that wider notice to the field of the possible extrusion problems and cartridge replacement be made.

The FAA recommends that fixed-base operators (FBO ’s), fuel farm operators, pilots, owners, operators, maintenance personnel, and anyone involved in aviation fueling operations check for the presence of the ACO-XXXXXC filter cartridge. Also, closely check fuel samples for the presence of contaminates. If you find gelatinous matter, thoroughly investigate the source. Document any filter cartridges found in stock or in service on the following “Product Recall” form.

If you require further assistance, contact Velcon Filters, Inc., at telephone number 1-800-531-0180 and ask to speak to “Aviation Technical Services.”

VELCON FILTERS, INC.,

PRODUCT RECALL I understand the circumstances of the Velcon Filters, Inc., product recall of the ACO-XXXXXC cartridges. Listed below are the ACO-XXXXXC cartridges that my company currently has in stock. I hereby certify that these cartridges will be destroyed upon receipt of replacement ACO-XXXXXK cartridges.

______________________________ _______ Name of Company Date _______________________________________ (Print) Name of Authorized Representative _______________________________________ Signature of Authorized Representative ___________________ __________________ Telephone Number FAX Number ________________________________________ Purchased From: Name of Distributor

MODEL NUMBER QUANTITY _________________________ _____________ _________________________ _____________ _________________________ _____________ _________________________ _____________ _________________________ _____________ _________________________ _____________ _________________________ _____________ MAIL TO:

VELCON FILTERS, INC.

MARKETING DEPARTMENT 4525 CENTENNIAL BLVD.

COLORADO SPRINGS, CO 80919-9951

FAA AC 43-16A September 1999 4

AIRPLANES BEECH Beech; Model E18S; Tailwheel Failure;

ATA 3220 During a landing, the aircraft tailwheel collapsed when it contacted the runway.

The technician took the aircraft to the hangar and jacked up the tail. When the weight of the aircraft was removed from the tailwheel, the tailwheel assembly lowered. An investigation revealed a broken bolt (P/N AN33DD) which is used to secure the tailwheel retraction cable.

The submitter suggested close attention be given to this area during inspections and maintenance.

Part total time not reported.

Beech; Models 24, C23, and 19 Series;

Structural Corrosion; ATA 5320 The submitter of this report found similar structural corrosion defects in Models 24, C23, and 19 series aircraft.

Corrosion was found at the forward attachment point for the fuselage channel (P/N 169-42000-91) at Fuselage Station (FS) 132. At this location, a fresh air duct passes through the channel. In one case, the forward channel attachment point was completely consumed by corrosion. Severe corrosion was also found at other various points on the fuselage where fresh air duct boots came into contact with the fuselage structure.

The submitter speculated the corrosion defects were caused by water leakage from windows and condensation from the air ducts.

In many cases, the insulation was wet which created an environment conducive to corrosion. He recommended that owners, operators, and maintenance entities be aware of the possibility of fuselage structural corrosion and conduct an inspection of the suspect areas. This inspection is very important if water leakage from the windows is evident.

Part total time average-1,500 hours.

Beech; Model C35; Bonanza; Improper Ruddervator and Aileron Repairs; ATA 5540 and 5751 During a maintenance inspection, the technician noticed “scab patches” on one aileron and both ruddervators.

Further investigation disclosed the “scab patches” were loose, and there was a considerable amount of corrosion present.

The blind fasteners, used to secure the aluminum patches to the ruddervator magnesium skin, worked loose. The aircraft maintenance records did not indicate when these repairs were made or whether any effort was made to balance the flight controls. Also, the ruddervator system had excessively loose bushings and worn rod-ends which produced very “sloppy” control. It was evident this aircraft was not in compliance with the numerous FAA Airworthiness Directives that addressed the ruddervator system.

The technician informed the aircraft owner that the flight control patches were not airworthy. The owner decided to ground the aircraft and asked the technician to perform a proper evaluation and repair.

The owner recently purchased this aircraft without the benefit of a maintenance inspection or an inspection of the maintenance records. However, the annual inspection was “signed off” when he purchased the aircraft.

The submitter stated, “Pay a reputable Airframe and Powerplant Mechanic for an airworthiness evaluation prior to purchasing an aircraft! The money you pay up front may save you many dollars after the sale and may save your skin!”

Aircraft total time-6,005 hours. Total time since annual inspection-25 hours.

September 1999 FAA AC 43-16A 5 Beech; Model V35A; Bonanza; Defective Oil Temperature Sending Unit; ATA 7720 The engine installed in this aircraft was a Teledyne Continental, Model IO-520B.

While investigating the cause of inaccurate engine oil temperature indications, technicians discovered a defective temperature sending unit. The maintenance records indicated this was the original sending unit installed when the aircraft was new.

The technician ordered and received a replacement sending unit. He conducted a receiving inspection, and discovered the replacement sending unit’s wire stud was loose and could easily be rotated by “finger pressure.” He rejected the replacement sending unit and contacted the vendor.

The vendor checked his stock and rejected four other sending units before finding a sending unit that did not have loose wire studs and threaded studs. He compared one of the new sending units to the original sending unit and discovered the stud on the original sending unit was tight and did not allow any movement. The vendor stated the crimping or staking process used to install the stud during manufacture may be deficient. A loose wire stud presents a problem when the wire is installed because there is no acceptable way to prevent the stud from rotating while the nut is tightened.

The submitter suggested that the manufacturer’s engineering staff evaluate the new sending units for adherence to the original design specifications. He also stated the original sending unit (P/N 1512926) listed in the Beech Parts Manual has been superseded.

Part total time-4,000 hours.

Beech; Model B90; King Air; Faulty Electrical Wiring; ATA 2450 After operating the air-conditioning system during a phase inspection, the technician smelled and saw smoke in the cockpit.

The technician investigated and discovered a wire (P/N P83A2) smoldering under the center cockpit pedestal at the isolation limiter bus. There are two wires (P/N’s P83A2 and P83B2) at this location. The wires are aluminum and run from the right wing starter relay bus to the isolation limiters in the cockpit. Except for the emergency bus, these wires provide electrical power to the entire aircraft without circuit protection. While removing the wires for replacement, one wire (P/N P83B2) broke at the starter relay. The wire was severely corroded and the insulation displayed evidence of excessive heat damage.

The aluminum wires were installed in Models 65-90 and 90-Series King Air aircraft through serial number LJ 440.

The submitter stated, “The old wires are dangerous and must be replaced.”

Part total time-10,007 hours.

Beech; Model B99; Airliner; Entrance Door Cracks; ATA 5210 The flightcrew reported that the pilot’s crew door was very difficult to close.

A technician lubricated and inspected the door latch mechanism. While inspecting the door hinges, he discovered a cracked upper forward hinge (P/N 99-420024-7). The 1-inch long crack ran along the hinge line.

The submitter speculated that the hinge crack was caused by flexing the door structure due to excessive seal thickness.

Part total time not reported.

FAA AC 43-16A September 1999 6 Beech; Model BE99; Airliner; Defective Main Landing Gear Torque Knee; ATA 3213 During a scheduled inspection, the technician discovered a crack in the left main landing gear torque knee.

Both the upper and lower torque knee (P/N 50-810323-7) halves were cracked near the center pivot bolt which connects the upper and lower halves. The cracks had progressed to the point where pivot bolt loss was imminent.

The submitter stated that hard landings, landing gear sideloads, and other factors may have contributed to this failure.

Part total time not reported.

Beech; Model B100; King Air; Defective Engine Starting Electrical Circuit; ATA 3260 The pilot reported that the left engine starter would not engage.

Maintenance technicians discovered a defective left main landing gear “squat” switch (P/N 444EN49-6). The “squat” switch contacts interrupted the engine start control circuit by not supplying electrical power to the start relay control box. The location of the landing gear “squat” switch makes it vulnerable to contamination, corrosion, and failure.

The submitter recommended that the “squat” switch receive frequent inspections.

Part total time-6,618 hours.

Beech; Model BE200; King Air; Interior Light Fixture Failure; ATA 3320 During flight, smoke filled the aircraft cabin.

The pilot evacuated the smoke and made a safe landing.

Maintenance personnel discovered the source of the smoke was a cabin light assembly (P/N 00741626) ballast. The ballast shorted, generated smoke, produced extreme heat, and distorted a nearby plastic window molding.

The submitter stated, “The heat intensity could easily have caused a fire and may have ended in a catastrophic accident.”

Part total time not reported.

Beech; Model 400A; Beechjet; Landing Gear System Failure; ATA 3230 The pilot reported that the 2-amp landing gear circuit breaker opened when the landing gear was selected to the “up” position. He placed the landing gear selector to the “down” position, and made a safe landing.

The technician discovered that two wires on the gear selector control switch were crushed and shorted together in the area of the cockpit center pedestal structure. The wires were repaired and rerouted to provide adequate clearance.

The submitter suggested closely inspecting this area at every opportunity.

Part total time-1,277 hours.

CESSNA Cessna; Model 172N (C172); Skyhawk;

Carburetor Problem; ATA 7322 On the first flight of the day, the student pilot reported the engine would not idle cutoff.

When he shut off the engine using the magneto switch, the propeller ran backwards.

The instructor stated the aircraft did not idle properly the previous evening; however, he assumed hot weather caused the problem.

A technician examined the engine and discovered the carburetor’s (P/N 10-5009) upper and lower body halves had separated approximately 0.125 inch. Evidently, the carburetor overhaul facility technician did not torque the bolts properly before he set each bolt’s lock-washer tab.

September 1999 FAA AC 43-16A 7 The submitter stated this is the third occurrence of the same problem involving three separate overhaul facilities.

Part time since overhaul-25 hours.

Cessna; Model 172RG (C72R); Cutlass RG;

Faulty Risistor; ATA 2460 During an annual inspection, the technician noticed smoke emanating from the radio rack.

An investigation disclosed the resistor (P/N S2041-50-16) for the cigarette lighter was damaged and smoking. He found burn marks on both sides of the glovebox side wall where the resistor is affixed. The nylon portion of the affixing locknut was completely melted. The ceramic insulator at the base of the cigarette lighter (P/N 0513052-20) was broken. He noted the 7-amp fuse and the 10-amp circuit breaker were not activated.

The submitter stated that the replacement parts contain a new-type lighter assembly (P/N 0513039-7) and an additional circuit breaker (P/N 60232-1). He recommended issuing an Airworthiness Directive (AD) requiring the installation of a second circuit breaker.

Part total time-3,315 hours.

Cessna; Model 172 (C172); Skyhawk; Airbox Part Missing; ATA 7160 During the first Phase I inspection, the technician discovered a part missing from the airbox assembly (P/N 0550364-7). There was a gap around the alternate air door where the part belonged.

Also, apparently due to the door hinge’s misalignment, filler material was used to fix a gap in the air inlet door assembly. Most of the filler material broke away leaving a ½-inch gap in the assembly. The remaining filler material displayed cracks.

The submitter replaced the airbox.

Part total time-50 hours.

Cessna; Model 172S (C172); Cutlass;

Misaligned Rudder Pedals; ATA 2720 This new aircraft had less than 100 hours of total operating time. During the first Phase II inspection, the technician noticed the rudder pedals on both pilot stations were not matching in their alignment.

The technician discovered the left station’s pedals had its mounting arm (P/N 0411307-0), on the right pedal, drilled incorrectly at the point where it attached to the crossover shaft.

At the point where the right station’s pedals attached to the crossover shaft, the left pedal was also drilled incorrectly.

The technician notified the manufacturer of this misalignment problem. The manufacturer sent parts that were properly drilled.

Part total time-97 hours.

Cessna; Model 172S (C172); Cutlass; Pilot Seat Support Problem; ATA 2510 When the pilot’s seat back was selected in the full-upright position, it was approximately 3 inches back and toward the reclined position.

The submitter discovered the seat back support fitting (P/N 0514215-8) was bent. He noted that this was the second fitting replaced on the same seat. The first fitting was replaced after only 23.6 hours of use. This is the fourth failure of the same part within his fleet of new Cessna aircraft.

The submitter stated past accident statistics show that a seat part failure, especially during a takeoff roll, may have grave consequences.

It is important for new owner/operators to be aware of the problem prior to a disaster.

Part total time-51 hours.

Cessna; Model 172S (C172); Cutlass; Skin Crack on Flap; ATA 5753 While performing a Phase I inspection, the technician noticed a crack at the trailing edge of the left flap assembly. The crack was located

FAA AC 43-16A September 1999 8 on the lower surface. It started at the fourth rivet from the inboard edge of the flap and migrated outboard for approximately 2 feet.

After the submitter notified the manufacturer of this defect, he received a new assembly.

Part total time-149 hours.

Cessna; Model 172S (C172); Skyhawk; Fuel Leak; ATA 7322 During the first Phase I inspection, the technician noticed the presence of fuel in the vicinity of the air inlet.

An investigation revealed that the specific point of fuel leakage occurred at the air inlet elbow (P/N 0550362-3) leading to the fuel control unit. A more extensive search disclosed that the overboard drain adapter, which is riveted to the air inlet elbow, was not properly sealed. The improper seal was not readily visible.

Part total time-50 hours.

Cessna; Model 310 (C310); Cessna 310; Worn Fuel Selector; ATA 2823 During an extensive aircraft inspection, the technician discovered that both fuel selector torque tube assemblies (P/N 0820000-5 and 0812000-13) were severely worn.

Tube (P/N 0820000-5) was worn at the fuselage grommet area, and tube (P/N 0812000-13) was worn at the bulkhead at Fuselage Station (FS) 557.5. The tube damage was only detectable because the tubes were removed.

Under normal inspection procedures, this defect may have gone undetected. The extent of the damage was approximately 65 percent to the perimeter of the tube and approximately 50 percent through the tube wall thickness.

The submitter stated owners with similar make and model aircraft, should remove the four shielded bearing blocks and inspect this area as soon as possible.

Part total time not reported.

Cessna; Model 402B (C402); Businessliner;

Fuel Blockage; ATA 2822 The pilot reported that he was unable to prime the right engine.

A technician discovered the right boost pump was producing inadequate pressure. He opened the fuel tank to remove and replace the boost pump and discovered a 2-½ inch square data tag (P/N 1C6-10) was unglued and resting directly below the pump’s fuel pickup tube. When the pump was activated in the priming process, the data plate was sucked up against the tube inlet, and the fuel flow was reduced to less than 10 pounds per square inch.

The submitter recommends that pumps with this type of data tag be replaced with the type of tag that is more permanently affixed.

Part total time-193 hours.

Cessna; Model 421C; Golden Eagle III;

Hydraulic Leak; ATA 2916 The maintenance department received a work order that indicated hydraulic fluid was visible in the nose compartment.

The technician discovered a hydraulic leak emanating from the reservoir. The fluid leak occurred at both ends of the sight tube (P/N 5117007-12) at the attach points. The technician discovered the same problem on a similar aircraft.

Due to the low failure time, the submitter stated this problem indicates a production flaw. The submitter cautions all owners and operators of similar aircraft to inspect for this problem. A complete failure of this tube would result in loss of the entire hydraulic supply.

Part total time-50 hours.

September 1999 FAA AC 43-16A 9

DIAMOND Diamond; Model DA20-C1; Propeller Attachment Bolt Failure; ATA 6111 The pilot reported that during an after-takeoff climb, a severe vibration occurred. He made a safe landing and summoned maintenance technicians.

The technician discovered the propeller spinner was cracked. After removing the propeller spinner, he discovered five of the six propeller mount bolts broken. It appeared the bolts failed due to shear stress. He sent the bolts to the manufacturer for inspection and evaluation.

The submitter stated the bolt attachment holes in the propeller flange were elongated which indicates the bolts were not torqued to the specified value.

Part total time-40 hours.

GRUMMAN AMERICAN Grumman American; Model AA5B; Tiger;

Defective Aileron Skin; ATA 5751 During an annual inspection and compliance with Airworthiness Directive (AD) 79-22-04, the technician discovered the left aileron skin was delaminated.

The upper aileron skin (P/N 5202035-516) delamination varied from 1 to 4 inches where the leading edge skin was bonded to the rib.

It was necessary to remove and replace the aileron.

The submitter stated that this area deserves extra attention during inspections and maintenance.

Part total time-1,675 hours.

LAKE Lake; Model LA4-200; Buccaneer; Loss of Engine Power; ATA 7160 This aircraft incorporated a Textron Lycoming, Model IO-360-A1B, engine which was modified by Supplemental Type Certificate (STC) SA2990WE. This STC allowed the installation of an engine turbocharger.

The pilot reported that with the throttle full open and the waste gate closed, the engine had excessively low boost.

The technician conducted an investigation and several contributing discrepancies were given credit for the engine power loss. The boost air inlet fitting weld, located at the bottom of the induction airbox, was cracked all the way around the circumference. This allowed some boost air to escape overboard. The welded attachment fittings between the airbox and the fuel injection control were cracked. He found numerous cracks in the airbox extending from various points of the circumferential weld. The airbox flapper valve hinge pins and hinge pin mounts were excessively worn and on the verge of complete failure. The rubber elbow that attaches the boost duct to the airbox assembly had a large rip and allowed the loss of more boost air. Some areas of the elbow were wrapped with “electrical tape” to cover worn places.

The submitter speculated that these defects combined to degrade engine performance. The weld cracking was credited to normal vibration and previously accomplished “unairworthy” weld repairs. Thorough and timely inspections, as well as proper repair techniques, should prevent these types of defects.

Part total time not reported.

FAA AC 43-16A September 1999 10 PIPER Piper; Model PA28-151 (P28A); Cherokee; You Say Your Head Was Where?; ATA 7322 After a landing, a fire started in the engine cowling.

The technician discovered the carburetor air-intake hose (P/N 99849-03) from the air filter was connected to the muffler. It should have been connected to the carburetor airbox.

(I bet that robbed a bit of horsepower!) The cabin heat duct was connected to the carburetor airbox.

These erroneous connections may have led to a backfire which ignited a leaking primer fuel flex line.

We’d hate to think of what would happen if this plane had a toilet to flush. People, lets stay tuned-in and pay attention out there.

Part total time unknown.

Piper; Model PA28-161 (P28A); Warrior II;

Broken Landing Gear Trunnion; ATA 3211 While on a training flight, after a touch-and-go landing, the instructor felt a severe vibration.

He landed the aircraft without personal injuries; however, the aircraft sustained damage to the right wing, the flap assembly, and the stabilator.

Observers on the ground reported that something was hanging from the right wing.

An inspection revealed the right main landing gear trunnion (P/N 65319-004) broke at the upper torque link attach ears. With the trunnion broken, only the brake hose held the lower strut and wheel assembly to the aircraft.

The submitter stated that he reviewed the maintenance records for this 1982 aircraft and found no entries of landing gear trunnion replacement. Apparently, this part was original on an aircraft used exclusively in flight school operations.

Part total time-9,478 hours.

Piper; Model PA28-180; Archer; Spar Cap Damage; ATA 5711 During an annual inspection, the technician found evidence of fretting at the left and right main landing gear legs (P/N’s 35644-04 and 35644-05) where they attach to the wing’s lower spar cap.

The technician also discovered the lower attach bolts (AN4-11A) were not properly torqued, and the attach point bolt holes were elongated on both the gear legs and the spar caps. This allowed a wearing motion between the gear legs and the spar caps.

The submitter states that the spar damage was caused by the improperly torqued bolts which caused the wearing motion between the parts.

He recommends checking bolts for proper torque during 100-hour inspections and annual inspections.

Part total time-4,040 hours.

Piper; Model PA28R-200 (PA28R); Arrow 200;

Alignment Cam; ATA 3211 After takeoff, the pilot could not retract the nose gear. He made a safe landing even though he experienced steering difficulty throughout the landing roll and taxi.

The technician discovered that the steering alignment cam was outside and to the left of its guide bracket (P/N 67107-00). This caused the cam to hit the bracket’s ear, thus, not allowing the landing gear to fully extend. Also, because the tire was not aligned it would not fully retract into the cowling. (Refer to the following illustration.)

The submitter stated that because of normally high torque throughout the takeoff roll, the pilot’s excessive right rudder application may cause the alignment cam to strike the ear on the alignment bracket during gear retraction.

The resulting bracket flex caused it to strike the trunnion housing, and the cam assembly came out of its track.

The submitter states the manufacturer has already welded a stiffener across the ear