This file contains the text of the General Aviation 
Airworthiness Alerts, AC 43-16, with graphics and 
illustrations removed.  The advisory circular is published 
monthly by the FAA Flight Standards Service. Items in the 
publication are selected from Malfunction or Defect Reports 
submitted by the general aviation public.  Items are 
selected for publication when the subject is likely to be of 
interest to a broad segment of the general aviation industry 
or when a particular safety issue is reported.  Inclusion of 
an item in the Alerts does not imply that a hazard exits or 
that an analysis has been conducted on any part or product.  
A free subscription to the Alerts is available by 
contacting:

        Regulatory Support Division, AFS-600
        ATTN: AFS-643
        P.O. Box 25082
        Oklahoma City OK 73125
        (405) 954-6487


                           ALERTS
                       SEPTEMBER/1995
                           INDEX

                         AIRPLANES
	
AERONCA
BEECH
BELLANCA	
CESSNA	
FOUGA	
LAKE	
PIPER	
STINSON	

                       HELICOPTERS

AGUSTA	
AMERICAN EUROCOPTER	
BELL	
HUGHES/SCHWEIZER	


                 AGRICULTURAL AIRCRAFT

PIPER	

                 BALLOONS AND GLIDERS

THE BALLOON WORKS	

        AMATEUR AND EXPERIMENTAL BUILT AIRCRAFT

KR-2	
LONG EZ	
ZODIAC	

             PROPELLER AND POWERPLANT

TEXTRON LYCOMING	

                   ACCESSORIES

SLICK MAGNETOS	

                    AIR NOTES

LINSEED OIL RESIDUE DISPOSAL	



                          AIRPLANES

                         AERONCA

Aeronca                       Fuel Gascolator
Model 7AC                     2821
Champ

After an accident caused by fuel starvation, an 
investigation determined the glass gascolator bowl had 
failed.

Although the glass bowl was broken, the safety wire and bail 
were still attached to the assembly. Champion Aircraft 
Corporation Service Hint #15 recommends the glass 
gascolator bowl be replaced with a metal unit. Previous 
failures, caused by vibration and/or overtorqueing of the 
adjustment clamp, prompted the issue of this document. This 
condition may also affect the many other aircraft using a 
glass gascolator bowl. 

Part total time-4,399 hours.


Aeronca                    Rudder Cable Damage
Model 7AC                  2720
Champ  

During an annual inspection, the left rudder control cable 
(P/N 1-2364) was found severely frayed.

Approximately 80 percent of the cable strands were broken at 
the point it passed over a 1-inch diameter pulley at the 
rear cabin bulkhead. A 1-inch diameter pulley at a different 
location was found not rotating and had a flat spot worn 
into the cable groove. The submitter stated these defects 
did not exist during the previous annual inspection and 
suggested more frequent inspections.

Part total time not reported.



BEECH

Beech                         Nose Landing Gear Collapse
Model E-18S                   3230

The pilot reported the landing gear failed to retract after 
takeoff, and the nose gear collapsed during landing. All 
three green down-and-locked indicator lights were 
reported to be illuminated prior to landing.

An inspection revealed the bolts, used to secure the nose 
gear retraction nut (P/N 221-4) and push-pull tube (P/N 221-
2), had failed. During an operational test of the landing 
gear, the wire connected to the landing gear motor control 
switch on the nose gear walking beam was found broken. 
Evidently, the motor shut off at the same time the wire 
failed. Also, the position indicator light switches were out 
of rig enough to allow a down-and-locked indication 
prior to the gear locking in the down position. The 
submitter speculated the motor control switch wire failed 
just prior to full extension of the gear and placed a 
tension load on the bolts previously mentioned. It was 
recommended an operational test be accomplished to assure 
the landing gear rigging allows the gear to attain the 
down-and-locked position prior to illumination of the 
green indicator lights.

Part total time not reported. 


Beech                          Wing Root Seal
Model F33A                     5350
Bonanza

During a day VFR flight, a loud disconcerting drumming noise 
and vibration was felt and heard. The sound was similar to 
that produced by closing the cabin door on a dangling 
seatbelt or a broken ADF antenna wire.

After a routine landing, it was discovered the wing root 
rubber seal detached from the lower side of the left wing, 
and had been slapping the fuselage and lower wing surface. 
This seal is normally attached by an adhesive and had been 
poorly installed after a recent aircraft paint job. The 
loose end of the seal was responsible for opening the 
belly drain door and bending its hinge. The submitter 
recommended this seal be inspected for security and 
condition during preflight and scheduled inspections.  

Part total time-1,200 hours. Time since seal installation 
was 30 hours.


Beech                         Elevator Control Push-Pull 
Model 35-C33A	Tube
Bonanza	2740

During a scheduled inspection, the elevator push-pull tube 
was removed for inspection. 

A hole was found at the aft end of the tube (P/N 95-524017-
8) at the point where the tube tapers. The hole was probed 
and found to be caused by internal corrosion. The rod-ends
were removed, and an inspection of the tube interior 
revealed extensive corrosion requiring replacement of the 
part. It is recommended all flight control push-pull tubes 
be given extensive scrutiny during scheduled inspections and 
maintenance.

Part total time-3,974 hours.


Beech	Engine Air Filter
Model F-35	7160
Bonanza

After installation of a Brackett air filter, the submitter 
found the manifold air pressure (MAP) was 2 inches (Hg) 
lower at takeoff power than with the original filter 
installed.

An investigation determined the differential pressure was 
opening the alternate air door. The alternate air door began 
to open at 21 inches MAP, and was fully open at 23 inches 
MAP. A new alternate air door spring was installed, and 
another operational test produced the same result. From 
reading this report, one would conclude the Brackett air 
filter was not allowing sufficient airflow to the engine. 

This problem was presented to the manufacturer who stated 
this was not normal. According to Brackett, one should  
normally see approximately 2 inches H20 drop or 1/5 inch 
Hg. This air filter system has been in use for many years, 
and the manufacturer is not aware of this type of previous 
occurrences. A review of the FAA Service Difficulty 
Reporting (SDR) data base revealed 53 entries associated 
with Brackett air filters since 1986. Only two of these 
reports cited symptoms described in this article. The cause 
of one report was attributed to excessive oil on the filter 
element, and the other to installing the assembly 
backward. Most of the other reports concerned water or 
ice saturation of the filter element during operation and 
deterioration of the foam filter element. 

The exact cause of this defect has not been determined. If 
additional information is obtained, it will be printed in a 
future edition of this publication.

Part total time-0 hours.



Beech	Landing Gear Extension Failure
Model B-60	3230
Duke

During a landing approach, the landing gear would not extend 
normally, and a burning odor was detected. When the gear 
was extended manually, a loud popping sound was heard. 

An inspection revealed the right main gear uplock roller 
(P/N 6NBC914YJ or NAS 505-65) was seized, and the roller 
would not disengage from the uplock block. The submitter 
speculated this caused the gear motor to burn out and bend 
the retraction rod (P/N 60-810057-617). The manufacturers 
maintenance manual requires lubrication and inspection of 
the uplock roller assembly each 100 hours of operation. 

Part total time-3,354 hours.


Beech	Pneumatic System Plumbing
Model B-90	3610
King Air

The pilot reported the pneumatic pressure, and vacuum was 
low and declining.

An investigation disclosed the pneumatic regulator was 
contaminated with black dust and larger pieces of 
debris. The contamination source was traced to a pneumatic 
supply hose (P/N 156001-10D-184) on the left engine. 
Approximately one-third of the internal hose lining was 
missing, and the remainder crumbled when the hose was even 
slightly bent. Although the hose had no identifying marks, 
the submitter believed it to be an incorrect part number for 
this installation. Exposure to engine-generated heat was 
blamed for the hose deterioration. 

This hose was reported to be 5.4 years old


Beech	Wing Flap Drive Bearing
Model C-90A	2750
King Air

During routine maintenance and lubrication, the wing flap 
drive gear (P/N 100-524074-1) bearing (P/N B36) was found 
with all of the needles missing. (Refer to the following 
illustration.)

The bearing cage and both races were all that remained in 
the gear assembly. No evidence of the missing needles 
could be found in the gearbox. Evidently, the bearing had 
been installed with the needles missing. The submitter 
did not offer any other conclusion. 

Part total time-3,378 hours.


Beech	Aileron Structure
Model C-99	5751
Airliner

During a scheduled inspection, a crack was found in the 
right aileron skin.

The crack was located on the forward side of the top aft 
outboard skin (P/N 99-130000-11) at the point where it 
attached to the aileron spar. The orientation of the 4-inch 
long crack is shown in the following illustration. The 
submitter stated a similar crack was found in the same 
location on another like aircraft by them. The cause of this 
defect was not given.

Part total time-6,750 hours.


Beech	Air-Conditioner Bearing   
Model B-200	Failure
Super King Air	2110

During a scheduled inspection, the air-conditioner system 
drive quill shaft (P/N 101-910108-1) was found sheared.

Further inspection revealed the aft support bearing (P/N 
206SZZC) appeared to have seized, spun in the drive pulley, 
and caused the drive quill to shear. The submitter stated 
this was their second experience with this type failure. 
Inadequate lubrication of the bearing was blamed for this 
failure. Since this is a sealed bearing, it should be 
changed at the first sign of abnormal operation.

Part total time-389 hours.


Beech	Engine Controls
Model 400A	7603
Beechjet

The pilot reported that while taxiing, the left engine 
failed to respond to power lever input. The engine was shut 
down using the firewall shut-off valves, and the aircraft 
was returned to the parking ramp.

An investigation revealed the ball joint swivel assembly 
(P/N 85043-3), located on the forward end of the engine 
control cable (P/N 45AS42010-13), had unthreaded from the 
cable. During an inspection of the right engine, the control 
cable was found loose on the cable shaft and could be 
rotated using light hand pressure. There was no damage found 
with either of the cable or ball joint swivel assemblies. 
After consulting the technical data, it was found that both 
engine control cable assemblies were missing a jamnut (P/N 
NAS509-4C) intended to lock the cable shaft to the ball 
swivel. (Refer to the following illustration.) The jamnut 
and ball swivel are part of the control cable assembly, and 
there is no independent listing for them in the Illustrated 
Parts Catalog. Since it is necessary to remove the jamnut 
and ball swivel to facilitate installation of the assembly, 
the submitter speculated the nut was omitted during the last 
installation. It was recommended that all operators conduct 
a one-time inspection of this assembly for condition, 
security, and proper installation.

Part total time-1,645 hours.



BELLANCA

Bellanca	Flight Control Cable Corrosion
Model 7GCBC	2700

During an annual inspection, three flight control cable 
turnbuckle ends were found severely corroded.

Two elevator cable ends and one wing flap cable end, located 
in the aircraft belly, were affected. The corrosion had 
consumed approximately one-half of the original cable end 
diameter. These turnbuckles had been safetied with brass 
safety wire, and the submitter speculated this along with 
exposure to a salt-air environment caused the corrosion. 
When the remaining flight control turnbuckles were 
inspected, all had been safetied with stainless steel safety 
wire, and no signs of corrosion were found. 

Part total time-1,408 hours.


Bellanca	Wing Spar Cracks
Model 8GCBC	5711
Scout

While installing new fabric on the left wing, several small 
cracks were found on the front wing spar.

The cracks were located near the strut attachment point 
where two doublers were installed. The doublers were located 
on the forward and aft sides of the spar, and the cracks 
appeared to originate in the spar at the corner where each 
doubler ends. All of the cracks were approximately .75-inch 
long, and it was necessary to replace the wing spar. The 
submitter did not speculate concerning the cause of this 
defect. It would be wise to inspect this area for similar 
defects at every opportunity.

Part total time-6,787 hours.




CESSNA

Cessna	Horizontal Stabilizer Rib 
Model 152	Cracks
Aerobat	5511

A recent report stated frequent findings of cracked and/or 
broken ribs on the horizontal stabilizer leading edge during 
scheduled inspections. 

The defective ribs (P/Ns 0432001-6 and 0432001-46) were 
primarily found on the right side of the stabilizer. The 
submitter speculated the cause was the elevator trim 
assembly (located on the right side) exerting excessive 
loads on the ribs. The aircraft maintained by this operator 
are used in a training environment, which may have been a 
contributing factor. Improper ground handling may also have 
been the cause of these defects. 

Part total time-7,804 hours.


Cessna	Alternator Failure
Model 172N	2421
Skyhawk

The instructor pilot reported smelling smoke and hearing a 
noise which appeared to originate at the alternator.

A visual inspection gave no indication of trouble; however, 
when the drivebelt tension was checked by hand, the front 
half of the alternator moved away from the rear half. The 
case bolt and safety wire were still intact and (at first 
look) appeared to be alright. A further inspection disclosed 
the case bolts had broken at the point where they thread 
into the rear case half and were held in place only by the 
safety wire.

Part total time not reported. 


Cessna	Horizontal Stabilizer     
Model R182	Structure
Skylane RG	5510

During a preflight inspection, a 1-inch crack was found on 
the left side of the horizontal stabilizer.

The crack was located in a bend radius of the rear spar 
attachment reinforcement bracket (P/N 0732101-4) adjacent to 
the outboard hole. The operator stated this was the second 
occurrence of this defect on the same aircraft and similar 
cracks had been found numerous times on other aircraft in 
their fleet. The exact number was not given. The submitter 
stated the most likely cause of this defect was improper 
ground handling of the aircraft. It was recommended this 
area be given special attention during scheduled 
inspections.

Part total time not reported.


Cessna	Alternator Intermittent   
Model T182RG	Operation
Turbo Skylane	2420

The aircraft owner complained that the alternator operated 
intermittently. Maintenance records indicated the alternator 
had recently been replaced by another maintenance facility 
in response to the same problem.

Although all electrical system components appeared to 
function properly, an engine operational check disclosed the 
problem was still present. It was decided to change the 
alternator control unit (P/N C611005-0103). When the unit 
was removed and turned upside down, water ran out of the six 
pin plastic connector. After the part was thoroughly dried 
and reinstalled, the intermittent alternator problem did not 
recur. The submitter suggested sealing the connector and 
wires or changing the unit mounting to preclude water 
entrance.
Part total time not reported.  


Cessna	Aileron Failure                                                                             
Model 195A	5751 
During an accident investigation, cracks were found in the 
area of the left aileron hinge attachment point to the rear 
wing spar.
Evidence indicated these cracks had grown over time and 
culminated in failure of the hinge point. The pre-existing 
cracks appeared to be concentrated at the lower attachment 
bolt (P/N AN3). Also, surface and skin lap corrosion was 
found in this area which may have contributed to weakening 
of the structure. It would be wise to conduct a rigorous 
inspection of this area during scheduled inspections and 
maintenance.
Part total time-3,000 hours


Cessna	Nose Landing Gear Down Lock  
Model P210N	Spring                
Centurion	3230
During and annual inspection, the nose landing gear down 
lock spring (P/N 9882024-1) was found broken.
The Cessna Pilots Association Newsletter published an 
article covering this subject, and Cessna has issued a 
replacement part which is less prone to failure. A broken 
down lock spring may lead to inadvertent nose landing gear 
retraction. All aircraft using the old-style spring should 
be inspected and the spring should be replaced.  
Part total time-1,531 hours.


Cessna	Exhaust System Failure    
Model T310Q	7810
The pilot reported that during an aftertakeoff climb, the 
left engine began making a deep throaty sound. A 
precautionary landing was made, and the aircraft was turned 
over to maintenance.
An inspection revealed the exhaust riser (P/N 0850710-31) on 
the number two cylinder had a hole in the lower side. Prior 
to this flight, the aircraft had been used for flight 
training which included single-engine procedures. After an 
interview with the pilot and further examination of the 
failed part, it was determined shock cooling may have 
been the cause. 
Part total time since overhaul-855 hours.


Cessna	Landing Gear Failure
Model 337A	3230
Skymaster

The pilot reported the left main landing gear would not 
extend and lock in the down position during a landing 
approach. All attempts to attain the down-and-locked 
position failed, and the aircraft was damaged during the 
landing.

An investigation revealed the two taper pins (P/N AN386-2-
14A), which are used to attach the left main gear universal 
joint to the actuator, had sheared. (Refer to the following 
illustration.) The submitter speculated one of the taper 
pins had a pre-existing crack which culminated in failure. 
The second taper pin failed due to the increased load 
imposed. During a preliminary visual inspection, the taper 
pins appeared to be intact. A physical inspection of the 
taper pin installation during scheduled inspections was 
recommended.
Part total time-2,487 hours.   


Cessna	Landing Gear Trunnion Crack
Model 402C	3213
Businessliner

During a preflight inspection, the pilot reported the right 
main landing gear strut was low. 

While attempting to service the strut, maintenance personnel 
discovered a crack approximately 4 inches long adjacent to 
the casting mark on the upper gear trunnion (P/N 5141103-
14). During disassembly, the strut barrel was also found 
cracked. A review of the maintenance records, and interviews 
with pilots who recently flew the aircraft, did not indicate 
any unusual or hard landings. The landing gear had been 
inspected thoroughly by maintenance personnel 4 hours prior 
to this occurrence. A metallurgical analysis was not 
accomplished; however, due to the high number of operating 
hours on this part, metal fatigue seems the most likely 
cause for this failure.

Part total time-16,399 hours.


Cessna	Landing Light Switch Failure
Model 550	3340
Citation

The pilot reported the right landing light was inoperative.

An investigation determined the cockpit control switch (P/N 
MS35058-22) did not have electrical continuity. The switch 
displayed evidence of heat damage on the bottom and at one 
terminal lug. The submitter did not offer a cause for this 
defect; however, it is likely the switch suffered from an 
internal electrical short circuit. 

Part total time-7,966 hours.




LAKE

Lake	Fuel Filter Bowl Corrosion
Model LA 4-200	2821
Buccaneer

During an annual inspection, the fuel filter element bowl 
was found severely corroded when it was being cleaned.

The corrosion had progressed through approximately 50 
percent of the wall thickness of the metal bowl (P/N 26413). 
The submitter stated a considerable amount of water was 
present inside the bowl which was blamed for the corrosion. 
If allowed to continue, the bowl wall thickness could have 
been penetrated, causing the potential for engine failure or 
fire. This filter element bowl was installed in accordance 
with Airworthiness Directive 76-12-11, and should be cleaned 
and inspected at every opportunity. 

Part total time-884 hours.




FOUGA

Fouga	Rudder Travel Restriction
Model CM 170	2720
Magister

During a scheduled inspection, the rudder travel was found 
to be obstructed.

An investigation determined the rudder pedal assembly was 
hitting a recently installed radio stack. The cause of 
this defect is obvious and requires close attention, 
planning, and operational tests to avoid incidents of this 
type. 

Part total time not reported.



PIPER

Piper	Fuselage Structure
Model PA 18-150	5311
Super Cub

During an annual inspection, a fuselage structural tube was 
found broken.

The tube ran diagonally and was located at Fuselage Station 
(FS) 127.5 on the right side. It was broken at approximately 
the center of the tube length. The defective tube was 
repaired, and an inspection did not reveal any further 
damage. Although an obvious reason for this damage was not 
evident, the submitter suspected a hard landing and/or 
unusual flight attitudes as the cause. The aircraft was 
operated with floats installed. 

Part total time not reported


Piper	Flight Control Yoke
Model PA 28-161	2701
Cadet

During a 100-hour inspection, the flight control yoke on the 
pilots side was found to have an abnormal amount of 
play in aileron movement. 

The universal joint was excessively worn, and the aileron 
sprocket stop pin was cracked. The stop pin was almost 
completely broken. Although the submitter did not offer a 
cause for this defect, it was most likely caused by wind 
gusts on the control surfaces. This condition should prompt 
maintenance personnel to inspect the entire flight control 
system for related damage.

Part total time-5,913 hours.


Piper	Pitot Mast Heater
Model PA 28-181	3411
Archer II

During an annual inspection, one of the two pitot mast 
heaters was found to be inoperative. Although the mast was 
warm, it would not get hot. 

This was a shark fin type pitot mast which is common to 
many other Piper model aircraft. Since pilots and many 
mechanics typically check pitot heat operation by feeling 
for heat, one heating element may be inoperative and go 
undetected. The 12-volt heating elements used in this mast 
are rated at 70 and 100 watts and are wired in parallel. 
They can be checked for operation by measuring their 
electrical resistance. The 70 watt heater has a resistance 
of 2.6 Ohms and the 100 watt heater has a resistance of 1.8 
Ohms. Their combined resistance should be approximately 1.1 
Ohms. Checking the system by this method may prevent some 
burned fingers.

With only one pitot heating element functional, operation of 
the aircraft in icing conditions may lead to loss of the 
pitot static system.

Part total time-1,114 hours.  


Piper	Nose Landing Gear Drag Brace
Model PA 28RT-201T	3220
Turbo Arrow IV

The pilot reported that during cruise flight, a loud 
bang was heard, and the red landing gear warning light 
illuminated. The landing gear was extended normally, and a 
safe landing was made.

An inspection revealed the nose landing gear upper drag 
brace (P/N 76426-03) was broken just forward of the 
hydraulic actuator attachment point. (Refer to the following 
illustration.) Piper has issued Service Bulletin (SB) 724A, 
which addresses this subject, and offers an improved part 
(P/N 76426-803) designed to prevent this type failure. 

Part total time-3,413 hours.


Piper 	Alternator Fan 
Model PA 31-350	2421
Chieftain

During a scheduled inspection, the alternator faceplate 
displayed signs of rubbing on the drivebelt.

It was suspected this was caused by a cracked fan assembly 
(P/N 90-2241). When the alternator was removed for further 
investigation, a crack was found at the drive key hole and 
ran in a spiral direction around approximately one-half of 
the fan. The crack then went straight to a fan blade cutout. 
A second crack had started to form a Y shape which was 
also oriented toward another blade cutout. Failure of the 
fan assembly was imminent. The cause of this defect was not 
given.

Part total time not reported.


Piper	Cabin Combustion Heater
Model PA 31-350	2140
Chieftain

While troubleshooting an overtemperature problem with the 
cabin combustion heater (Janitrol), the combustion air 
safety switch (P/N B42036) was found stuck in the closed 
position.

The combustion air blower system had air leakage and did not 
supply sufficient airflow to support proper combustion. The  
safety switch did not open to shut the heater down, and it 
ran until the overtemperature switch deactivated the system. 
A malfunction of this type heater can be deadly and deserves 
close attention during inspections and maintenance.

Part total time not reported.


Piper	Engine Fire
Model PA 32RT-300T	8120
Turbo Lance II

Information for the following article was taken from an FAA 
aircraft incident report submitted by Mr. Greg Minarik of 
the Fresno, California Flight Standards District Office.  

While conducting a parachute jump flight, the pilot noticed 
an acrid odor in the cockpit during the aftertakeoff climb. 
The odor was compared to what might be generated by burning 
rubber or fiberglass. After a short time, the engine began 
to miss, and the engine operating sounds became deep and 
throaty. The cockpit temperature began to increase 
rapidly, and flames were visible over the cowling, filling 
the cockpit with smoke. The four skydivers evacuated the 
aircraft at an altitude of 900 feet AGL, and the pilot made 
a 180 degree turn to the departure airport. While on short 
final approach, the landing gear failed to extend normally, 
and there was insufficient time for emergency extension. The 
aircraft was landed on a grass surface. There were no 
personal injuries, and the aircraft damage was classified as 
minor.   

An investigation revealed the turbocharger exhaust coupling 
(P/N 556-108) and turbocharger tailpipe (P/N 98705-2) 
failed, allowing hot exhaust gases to fill the engine 
compartment causing the fire. 

Airworthiness Directive (AD) 80-20-05 requires a one-time 
inspection of these parts. The submitter recommended these 
parts be inspected at frequent intervals and that the 
manufacturers service manual (SM) be adhered to when 
accomplishing inspections. The SM requires an inspection of 
the turbocharger tailpipe coupling clamp at 50-hour 
intervals, and it would be advisable to inspect the entire 
assembly at the same time.

Part total time-1,850 hours


Piper	Engine Failure
Model PA 34-200T	2840
Seneca III

The pilot reported the left engine quit in the same manner 
as if the mixture control had been pulled. A safe single-
engine landing was made.

An investigation disclosed the copper fuel line running from 
the fuel flow/pressure indicator to the fuel flow divider 
had broken just behind the B nut at the flow divider 
end. This caused a loss of pressure to the fuel injector 
nozzles. The line had been properly supported and clamped; 
however, vibration appeared to be the cause of failure. The 
submitter suggested using a line constructed from a more 
substantial material than copper for this installation. Of 
course approved data would be required to make such a 
change.

Part total time not reported.


Piper	Engine Exhaust Pipe/Heat Muff
Model PA 46-350P	7800
Malibu Mirage

During a scheduled inspection, the right tailpipe/heat muff 
assembly was found cracked around the circumference at a 
weld. (Refer to the following illustration.)

Also, the heat muff had worn through the flange and was no 
longer sealing against the tailpipe. The submitter 
speculated the cause of this defect was a design problem 
with the tailpipe support. The support is attached to the 
heat muff which, along with extreme heat differentials,  
seems to stress the heat muff weld. This condition allows 
exhaust fumes to enter the cabin creating a very hazardous 
situation.

Part total time not reported.


Piper	Engine Mount Corrosion		
Model PA 60-601P	5312
Aerostar

During unscheduled maintenance, the right engine mount frame 
tubing was found severely corroded.

Several areas of corrosion were found, all of which were 
covered by a protective heat shields. (Refer to the 
following illustration.) The stainless steel heat shields 
were lined with a fibrous material and were installed in 
1981 as part of Supplemental Type Certificate (STC) SE978NW. 
The submitter stated the fibrous material held moisture in 
contact with the steel tubing causing the corrosion. The 
severity of corrosion, in this case, substantially 
compromised the structural integrity of the engine mount 
system, and jeopardized safe operation of the aircraft. It 
is recommended a one-time inspection of the affected area be 
accomplished by all operators to ascertain the condition of 
the engine mount tubing. 

Part total time not reported.



STINSON

Stinson	Rudder Spar Structural Cracks
Model 108-1	5541
Voyager

During an annual inspection, the rudder spar was found 
cracked.

There were two cracks, one on each side of the spar channel 
radii, approximately 1 inch long. The cracks originated at 
the lower end of the spar and traveled upward. This area is 
adjacent to the tailwheel yoke attachment point, and it was 
believed vibration from landings was the main cause of this 
defect. There have been several other reports of similar 
defects on Stinsons as well as other tailwheel equipped 
aircraft. The causes appear to be high-speed taxi on rough 
surfaces, landings on rough surfaces, and improper landing 
techniques. These conditions should be avoided; however, if 
any of these conditions are experienced, an inspection of 
the tailwheel and adjacent structure should be accomplished.    

Part total time not reported.



HELICOPTERS

                           AGUSTA

Agusta	Main Rotor Servo
Model A109A	6730
Mark II

While performing routine maintenance and using a hydraulic 
mule, a stream of Mil-L-5606 hydraulic fluid was discovered 
leaking from the right hand aft servo (P/N 109-0110-42-5). 
Further investigation revealed the leak was coming from the 
aft weep hole located at the split line of the servo. 
Technical Bulletin (TB) 109-72 deals with similar leaks at 
the upper body of the servo actuator. The submitter stated 
that this problem, although not addressed in TB 109-72, can 
result in a total loss of fluid in the number 2 hydraulic 
system reservoir. 

Part total time since overhaul-1,254 hours.



AMERICAN EUROCOPTER

American Eurocopter	Cockpit Sliding Vent Window
Model BK117-2	5210
Space Ship

The pilot reported the right cockpit sliding vent window 
(P/N 117-24163-86) separated from the aircraft during 
flight.

It was speculated air turbulence, vibration, and cracks 
adjacent to the handle assembly caused the window to be 
lost. The submitter stated cracks typically develop near the 
handle assembly due to the handle hitting the solid window 
during operation. There was no damage to the airframe or 
rotor blades attributed to this incident. This window and 
the latching mechanism should be inspected for defects at 
every opportunity.

Part total time-32 hours. 


Ameican Eurocopter	Right Hand Sliding 
Model BK117-2	Vent Window
Space Ship	5210

The pilot reported the right sliding cockpit window 
(P/N 117-24163-86) separated from the aircraft during 
flight. 

It was speculated air turbulence, vibration, and cracks 
adjacent to the handle assembly caused the window to 
separate. The submitter stated cracks typically develop near 
the handle assembly due to the handle hitting the solid 
window during operation. Neither the airframe nor the rotor 
blades sustained damage resulting from this incident.  This 
window and the latching mechanism should be inspected for 
defects at every opportunity.

Part total time-32 hours.


Bell 	Starter Generator
Model 206L-3	2435
Long Ranger III

While performing a power recovery following an autorotation,  
the engine would not return to 100 percent N2 (power turbine 
RPM) when the throttle was rolled on. The RPM only 
returned to 97 percent N2. All the engine controls were 
replaced; however, the problem remained. A Bell Helicopter 
Technical Representative recommended replacing the starter 
generator. It was explained that starter generator 
vibrations have, in a few instances, interfered with the 
operation of the governor. The starter generator was 
changed, and the problem was resolved. 

Part time since overhaul-841 hours.  


Bell 	Tail Boom Assembly
Model 206L-3	5302
Long Ranger III

While performing a routine inspection, a crack was 
discovered on the aft portion of the tail boom assembly. The 
crack was L-shaped and approximately 10 inches long. The 
crack appeared to have started at one of the rivets used to 
mount the tail rotor gearbox mount casting to the tail boom 
skin, and it ended on the right side of the tail boom at the 
skin splice. The pilot reported no unusual vibrations in the 
airframe or rudder pedals on the previous flight. The 
submitter suspected the cause of this defect was an out-of-
balance tail rotor. The submitter suggested that Bell 
Helicopter Textron amend their 100-hour inspection form to 
include checking the tail rotor dynamic balance. 

Part total time not reported.  


Hughes/Schweizer	Strut Assembly
Model 269B	3270

An accident investigation was conducted after the helicopter 
self-destructed when a ground resonance condition was 
encountered. During the inspection, it was noted that both 
the left hand shock strut and skid attachment lugs were 
severely corroded (exfoliation) and separated. The submitter 
suggested removal of all shock struts during annual/100-hour 
inspections to ensure no corrosion exists in these areas. 

Part total time not reported. 



AGRICULTURAL AIRCRAFT

PIPER

Piper	Structural Tubing Cracks
Model PA 36	5311
Pawnee Brave

When the hopper was removed for repair, an inspection 
revealed cracks in the engine mount tubing clusters.

The tubing was cracked aft of the firewall, adjacent to the 
top engine mount attachment points. Airworthiness Directive 
(AD) 79-12-09, which requires installation of gussets in 
this area, had been accomplished, and it appeared these 
cracks developed after that installation. One of the cracks 
was approximately 2 inches long. The submitter did not offer 
a conclusion concerning the cause of this defect.

Part total time-4,550 hours.



AMATEUR AND EXPERIMENTAL AIRCRAFT

KR-2	Propeller Hub
	6114

The first flight of this amateur built aircraft ended with 
an accident when the propeller separated from the converted 
Volkswagen engine.  The cotter pins, through the prop hub 
attachment bolts, had sheared and the bolts backed out of 
the bolt holes.  The owner/builder stated he had not checked 
the bolts for proper torque.

Part total time - 60 hours.


Long Ez	Oil Cooler
	7921

While in cruise flight, the oil cooler ruptured at the 
output end of the oil cooler. This caused a rapid loss of 
oil and ensuing engine failure. An on-airport landing was 
performed without further incident. The submitter suspected 
the solder flux was not thoroughly cleaned from the tank (an 
improved method of cleaning these tanks has since been 
implemented), and caused a thinning of the material at the 
output end of the oil cooler during manufacture. The above 
mentioned oil cooler is part of a certified engine that is 
installed on the Cessna CE-172M. 

Part total time-2,200 hours. 


Zodiac	Propeller Bolts
	6110

During a power change while flying in the airport traffic 
pattern, the propeller departed the aircraft. Examination of 
the six .25-inch attachment bolts indicated they had failed 
at a point flush with the crank shaft flange. All these 
bolts appeared to have been overtorqued at installation only 
11 hours prior to the accident. The submitter suggested that 
all operators of Rotax engines using .25-inch propeller 
bolts, check for condition and proper torque of these bolts. 

Part total time-11 hours. 





HOT AIR BALLOONS AND GLIDERS


THE BALLOON WORKS

The Balloon Works	Deflation Line Pulley Failure
Model Firefly 11	5102

While attempting to deflate the balloon, the eyebolt used to 
retain one of the two deflation line pulleys broke.

The pilot stated it took three people and extraordinary 
effort, strength, and time to deflate the balloon. 
Fortunately, the winds were light during this event. A high-
wind landing could have been dangerous without the 
mechanical advantage of the pulley system. In addition to 
anchoring the deflation line pulley, the eyebolt is also 
used to fasten the heater superstructure to the basket. 
Therefore, with the eyebolt broken the heater support system 
is also compromised.

Inspection of the eyebolts for cracking, bending of the 
shank, and visible damage at every opportunity is 
recommended. This is especially important on high-time 
balloons.

Part total time-80 hours



PROPELLERS AND POWERPLANTS

TEXTRON LYCOMING

Textron Lycoming	Cylinder Damage
Model O-235-L2C	8530

This engine was installed in a Piper Model PA 38-112 
aircraft.

While the cylinders were removed for accomplishment of 
Supplemental Type Certificate (STC) SE792NW, all four 
displayed evidence of pitting on the cylinder walls. The 
camshaft lobes and lifter lands had flat spots, pitting, and 
excessive wear.

The submitter speculated this damage was caused by corrosion 
which occurred during a long period of inactivity. The 
maintenance records and recording tachometer indicated only
3.2 hours of operation between March 1991 and August 1993. 
The maintenance records did not indicate any preservation 
procedures had been accomplished as recommended by Textron 
Lycoming Service Letter L4180A. It seems neglect resulted in 
some very costly repairs in this case.

Part total time since overhaul-1,546 hours.



Textron Lycoming	Push Rod Failure
Model O-235-L2C	8530

This engine was installed in a Beech Model 77 aircraft.

While investigating the cause of excessive valve clearance, 
all of the push rods were found to have the wrong part 
number. 

Airworthiness Directive (AD) 80-25-02, which references 
Service Bulletin (SB) 453, requires installation of an 
improved push rod. (Refer to the following illustration for 
push rod part numbers and markings.) The push rods found, in 
this case, were not in compliance with the AD, and displayed 
signs of damage described in the previously referenced 
documents.

This operator contacted the manufacturer who stated the 
records indicate the engine was shipped from their facility 
to Beech with push rods that were in compliance with the AD. 
The aircraft records did not indicate the push rods had been 
changed since delivery of the aircraft. The origin of the 
improper push rods remains a mystery. 

It would be wise to check compliance with the AD at every 
opportunity and make appropriate maintenance record entries.   

Part total time-1,491 hours




ACCESSORIES

SLICK

Slick	Improper Magneto Points
Model 4250R	7414

This magneto was installed on a Textron Lycoming O-360 
engine in a Cessna 172N aircraft.

After a complaint of an engine miss on one magneto, it 
was removed and examined. It was found the point gap had 
closed down, and the points were an improper type for 
this magneto.

Since these points had been recently installed, the 
installing facility was called. According to their 1993 
edition of the manufacturers manual, the points (P/N M3637) 
were correct. According to the 1994 edition of the 
manufacturers manual (and 1989), the correct part number is 
M3081. Another call to the manufacturer verified the mistake 
was in the 1993 manual. If there is any doubt about the 
correct use of a part, it should be verified before 
installation.

Part total time-68 hours.




AIR NOTES

LINSEED OIL RESIDUE DISPOSAL

After using linseed oil as a corrosion inhibitor in a pair 
of aircraft wing lift struts, the soaked paper towels used 
to remove the residue were deposited in a trash barrel.

Approximately 1 hour later, the odor of overheated material 
was noticed. While investigating the source of this odor, 
the linseed oil-soaked paper towels in the trash barrel were 
found to be near the point of spontaneous combustion. The 
entire barrel was warm to the touch and the compacted paper 
towels were charred in the center. Left unattended, the 
resulting fire may have destroyed the hangar and its 
precious contents. 

There are several precautions which should be observed when 
disposing of excess materials, and the best source of 
information on this subject is your local fire department.  
Their advice should be sought and adhered to strictly. Many 
of the materials we use every day have the potential for 
disaster, either alone or in combination with other 
materials, when not properly handled, disposed of, and/or 
stored.  

Our thanks to the submitter from Florida for the information 
contained in this article.



