Squawk Box: 07/06


The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.


Cessna Single Engine Airplanes
Fuel Strainer Orientation

The FAA has been advised that some fuel strainer assemblies may have been originally installed or are being put back into service improperly. Cessna single-engine airplanes may have the fuel strainer assembly installed with the fuel flow arrow oriented against the fuel flow path. Although fuel may freely flow, contaminants may not be removed during a normal check of the fuel strainer. The FAA recommends all owners and operators check fuel strainer orientation at the next inspection to ensure proper orientation. Part Total Time: n/a.

Cessna 421B
Malfunctioning Heater Fuel Pump

The pilot reported the heater had stopped during flight. Based on burn marks on the outside of the pump housing, a maintenance shop determined the heater fuel pump had malfunctioned and caught fire.The pump supplier told the shop the problem was known and involves the fuel regulator in the wings on the Cessna 400 series, which seem not to allow enough fuel to go through to keep the pumps operating correctly, allowing them to overheat and fail. Part Total Time: 53.0 hours.

Piper PA23-250
Broken Main Landing Gear Link Bolt

The submitting technician found p/n 402-427 bolt broke on landing. This bolt is in the landing gear link assembly, p/n 16240-5. The right main gear folded aft and the tire rode on the right flap. As the FAA noted, compare the total cost of this damage to replacing a $10 bolt every 2000 hours.Part Total Time: 4898.0 hours.

Piper PA28R-200
Cracked Landing Gear Nutplates

The submitting technician discovered all four nutplates holding the forward main landing gear trunnion bolts were cracked. The lower inboard nutplate (p/n MS 21047-L4) was cracked vertically down its threads. The remaining three nutplates were cracked in the rivet tabs. Since the aircraft is a training aircraft that sees its share of hard landings, fatigue is suspected.Part Total Time: Unknown.

Piper PA31-350
Mis-Bored Nose Gear Cylinders

Two brand-new nose landing gear cylinder assemblies (p/n 45314-05) were found with incorrectly machined center bores. The bore is too small at the top, which doesnt allow the upper bearings (p/n 751363) full travel to the top of the cylinder. This could cause the bearings to jam in the bore and the landing gear to malfunction upon retraction/extension.Part Total Time: 0.0 hours.


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