SDR's and MX Alerts

CESSNA 182Q: This discrepancy was found by a mechanic while cleaning the aircraft's firewall after engine removal. An electrical cable (P/N D-PA13) between the auxiliary power and starter relays had burn marks indicative of arcing. Immediately across from the damage was the pointed end of a sheet metal screw protruding through the firewall. The function of this particular screw is for attachment of a plastic shield on the aft side of the firewall protecting the elevator cable pulley. This screw was reversed, allowing for its head to be on the forward side of the firewall. The damaged cable was replaced with a new part. Part total time: 4,642.0 hours.

DASSAULT DA-50: Maintenance personnel first became aware of a problem when the nose tire on this aircraft began to lose pressure over a two- or three-day period, dropping 10 to 15 percent during the night. The submitter stated, "subsequent inspection of the tire and wheel assembly revealed air escaping through the casting adjacent to the raised valve core boss. Liquid leak detector also confirmed the leak and location. This is the second [nose] wheel (P/N 9543426) to develop a leak in the same area. [The first nose wheel] was returned to Aviall for evaluation inspection. [Its] disposition is not known at this time." He noted a Malfunction and Defect Report was not submitted for that first occurrence, but a Falcon Jet Service Condition Report was initiated. The wheel's manufacturer was given as Aircraft Braking Systems. Part total time: 1,644.0 hours.

SCHWEIZER 269C: An annual inspection of this aircraft detected an abnormal "rusty brown" coloration in the grease lubricating the drive shaft, distinctly different from the expected black hue of Anderol lubricant. This drive shaft (P/N 269A5559-003) had accumulated 414.2 hours of a 6,000-hour life limit. The submitter stated, "the splines were worn beyond limits..." and evidenced excessive corrosion and pitting. "The speculation of Schweizer and our facility is that the grease was contaminated." (See the following article for similar findings on a second helicopter.) Part total time: 414.2 hours.

SCHWEIZER 269C-1: A 600-hour inspection revealed the same brown colored grease as reported in the previous report. This drive shaft (P/N 269A5559-003) had accumulated 600 hours of a 6,000-hour life limit. The submitter stated, "the splines were worn to the thickness of a piece of paper..." from their original measurement of .090 inches. Again the conclusion was submitted as: "The speculation of Schweizer and our facility is that the grease was contaminated. [This is the] first 600-hour inspection of this helicopter, [it having] the same grease since delivery from Schweizer Aircraft." (A separate report was submitted on this aircraft's associated drive part, the lower pulley shaft, P/N 269A5498-005, reflecting the same description, time, and condition of "worn beyond limits." This information will be included in the SDR database.