Cessna Pilots Association — February 2009
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General Aviation Alerts SDRs & Safety Issues

Cessna (Multiple Models) Pilot & Copilot Seat Tracks 10/2008 (The following maintenance admonition is provided by Aerospace Engineer Hieu Nguyen from the Wichita Aircraft Certification Office. Effected Cessna models are as follows: T303, 336, 337 and all legacy, pre-1986 single-engine models including 150, 152, 170, 172, 175, 177, 180, 182, 185, 188, 190, 195, 205, 206, 207, and 210. Relevant ATA codes include 5310 and 5347. Contact information can be found at the article’s end.)

“This Aviation Maintenance Alerts article is written to encourage owners, operators, and maintenance technicians to adhere to the requirements of Airworthiness Directive (AD) 87-20-03R2. The AD was issued because of pilot/copilot seat slippage due to the latch pin not properly engaging in the seat rail/track. When the pilot/copilot seat’s primary latch pin does not properly engage in the seat rail/track, seat slippage may occur, causing pilots to be unable to reach all the controls which could lead to loss of control of the airplane.

“Compliance with AD 87-20-03R2 should have eliminated accidents and Service Difficulty Reports (SDR’s). However, in the past decade we have seen a resurgence in the number of accidents reported by the NTSB and in SDR’s. This may indicate the inspections of the seat tracks are not being adequately performed or existing problems are not being corrected.

“Cessna has made available a secondary seat stop that can be installed for additional safety in the event the primary latch pin is not properly engaged in the rail/track. For airplanes not yet in compliance we recommend installation of the secondary seat stop on both the pilot and copilot seats in accordance with Cessna SEB07-5R1 or MEB07-1R1. For airplanes that already have the secondary seat stop installed, the FAA recommends inspection and replacement (if necessary) of P/N 505590- 401 Reel Assembly in accordance with Cessna SEB07-8 or MEB07-2. Reports have been made of secondary seat stops that have malfunctioned; however, the reel is designed to prevent slippage if such an event occurs.

“For additional information on the seat rail/track parts inspections, we suggest reviewing AD 87-2-03R2. Cessna SEB07-5R1 or MEB07-1R1 covers secondary seat stop installation data. Cessna SEB07-8 or MEB07-2 provides information for the inspection/replacement of the Reel Assembly, P/N 505590-401. The following table describes the installations for various models; however, because of the limited 8 inch seat travel, Models 150 and 152 do not have service kits.” Cessna T210L Erratic Operation of Flap Follow-Up Cable 10/2008 “I ordered a new, Cessna flap follow-up cable (P/N 9860058-1), “ says a mechanic, “to replace the original cable (it had become defective due to normal usage and age). This cable is similar to a throttle cable—(having) an inside cable which slides in an outside housing. Upon installation of the new, Cessna flap follow-up cable the operation was (observed to be) very rough and intermittent. Smooth operation is critical to meet maintenance manual specifications (and the aircraft’s flight manual requirements for certain specified flight conditions).

I contacted the Cessna Service Center...and then Cessna Technical Support direct. Cessna assured us (verbally) the cable has been manufactured to original specifications. From first glance the cable is obviously constructed in a different manner and of different material from the original part (for this and other aircraft utilizing the same part). Cessna Technical Support verbally stated the cable must meet a QC standard of operating smoothly with a 4 inch radius around a 90 degree bend. After (installation) of the new cable the operation (was observed) to be stiff, with ‘catches’ in its travel—as if the cable was snagging the cable housing when placed in one 6 to 8 inch radius bend. Multiple bends are required for installation in the aircraft. Each additional bend compounds the roughness of its travel. This cable operates travel limit switches for specified degree of flaps as set by the pilot at the flap selector handle. The maintenance manual only allows for a couple of degrees variance from the flap selector settings and the actual flap position. Rough operation causes an inability to set switches and the cable to produce consistent results (as required by) the maintenance manual parameters and the flight manual for specified flight configurations. This Is the second of two new cables in this condition ordered for this aircraft. Upon further contact with Cessna they could provide no other options or advice, (indicating) all new cables will perform in this same manner.” A search of the FAA Service Difficulty Reporting System data base reflects four such entries for this part number. Thankyou for the detailed description—I’ve experienced the same difficulty in other applications.

Part Total Time: 0.00 hours.

Alternator E3FF10300AA Low Voltage Output 10/2008 An unidentified submitter describes alternator difficulty for a Cessna P210N behind a Continental TSIO-520P. “During day flight the ‘low voltage’ light illuminated and the bus voltage dropped below 24 volts. The pilot minimized loads, did a manual gear extension, and landed without incident. The charging system was troubleshot by an A&P mechanic who found the alternator output to be 26 volts, unloaded. With 50% load on the bus the alternator voltage would drop below 24 volts. This alternator was overhauled by Kelly Aerospace Power Systems.” (Time since overhaul: 50.0 hours; read next for continuing saga.

A search of the FAA Service Difficulty Reporting System data base returns 6 reports for this part number.)

Part Total Time: (unknown).

Alternator E3FF10300AA Low Voltage Output 10/2008 (The same aircraft and submitter continue here, a second alternator and 10 hours later....) “During a night, instrument approach the (aircraft’s) low voltage light illuminated and the bus voltage dropped below 24 volts. The pilot recycled the alternator switch but was unable to keep the alternator on line. He reduced the loads an successfully executed an approach— landing without incident. The charging system was troubleshot by an A&P mechanic who found the alternator output to be 26 volts, unloaded. With 50% load on the bus the alternator voltage would drop below 24 volts. This alternator was overhauled by Kelly Aerospace Power Systems.” (Time since overhaul: 10.0 hours.)

Part Total Time: (unknown).

Alternator DOFF10300; Broken/ Missing Diode Studs 10/2008 (An A&P not associated with the previous two reports provides this description of another failed alternator. The engine is a Lycoming O-320 pulling a Cessna 172 through the clouds.)

“This alternator was overhauled by KELLY AEROSPACE. It operated less than 50 hours, then failed. The stud that holds the diode plate in the alternator was broken, and the second stud was loose. This has been an ongoing problem with Kelly Aerospace overhauls.

We are a small shop, yet we have had many failures with this product in the past two years. Approximately 70% of the Kelly overhauls we have installed have gone back for warranty. Problems include loose drive pulleys, loose hardware, short circuits, dead field windings, and defective brushes….” (Part time since overhaul: 46.0 hours.)

Part Total Time: (unknown).

Cessna 140 Fitting Corroded PN 0425118 LT TE Flap 10/2008 The part was beginning to rust through in location responsible for attaching the Lt. flap to the flap control.

The defect was found during an annual inspection. Probable cause was rusting due to age. A more thorough inspection of the area during preflight should help detect the problem so that corrective action can be taken Cessna R172K Nose Strut Valve Damaged PN S18271 10/2008 A new valve was ordered and installed to cure a suspected leak in the valve core.

The new valve arrived with a bright appearance, either chrome or nickel plated. With the new valve installed, the strut leak worsened. An external insp revealed that the cosmetic plating was flaking from the hex flats. The valve was removed and it was found that the plating was also flaking in the threadarea, and this resulted in a leak around the valve. This valve employs an NPT Thread (1/4 inch pipe thread) and the threads form the seal when installed.

The remaining plating was easily scraped from the threads with a pick and the valve was reinstalled without further difficulty. Submitter admits that the plating results in an attractive part, however the manufacturer may wish to stop plating the threaded area.

Cessna 182N Impulse Coupling Failed 10/2008 Pilot performed pre-flight inspection and discovered oil on forward portion of cowling, slight oil residue on windshield.

Mechanic removed top cowling to investigate, discovered magneto housing shattered at area immediately adjacent to impulse coupling. Apparently impulse coupling engaging mechanism somehow contacted actuating pin while operating (or engine backfired, we don`t have further information to ascertain this condition) shattered magneto body hsg.

Magneto was still firing, fixed to engine (not loose) engine ops was reported normal upon arrival of last flight, which seems to indicate that magneto had operated in this condition for what appears to be at least an hour or more.

No misfire or magneto drop detected.

Cessna TU206G Intake Duct Cracked PN 125083029 10/2008 Manufacturer supplied engine intake duct before the air filter is subject to cracking in multiple locations. This particular A/C and another identical model A/C this facility maintains, have been converted to another engine after the STC conversion. Cracking problem has increased significantly.

Have contacted STC holder, they have responded with a scheme to reinforce this duct. This repair station is looking into this alteration to this duct which may require DER support. At present, the ducts are requiring repairs of replacement every 50 hours. A PMA replacement duct made from composite material is no longer available Cessna TU206G Intake Duct Cracked PN 125083029 10/2008 Manufacturer supplied eng intake duct before the air filter is subject to cracking in multiple locations. This particular aircraft and another identical mode aircraft this facility maintains, have been converted to an IO-550-F eng. After the STC conversion, the cracking problem has increased significantly. Contacted the STC holder and have responded with a scheme to reinforce this duct.

This repair station is looking into this alteration to this duct which may require DER support. At present, the ducts are requiring repairs or replacement every 50 hours. A PMA replacement duct made from composite material is no longer available.

Cessna 210M Cable Broken PN 505530401 10/2008 Mfg service kit PN SK210-174, (Ed.

Note: Secondary Seat Stop Service Kit), cable assy broke at threaded end after the stop nut, seven weeks after installation.

Appears thread wall is too thin leading to fatigue.

Cessna 402C Selector Valve Damaged PN 9102011 Lt. Wing Fuel 10/2008 At climb power, Rt. fuel flow dropped to 90 pph. Aux pump on low fixed problem temporarily. Fuel flow dropped again and Lt. engine surge. Returned to departure airport and landing without incident. Mx removed and replaced Lt. fuel selector valve. Also replaced aux fuel pump and crossfeed valve as a precautionary measure.
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