Wear and Tear

The following information is derived from the FAAs Service Difficulty Re-ports and Aviation Maintenance Alerts.


Cessna 310L

Cracked Wheel

A mechanic writes, “Upon changing a tire on a Cleveland wheel assembly on this aircraft, it was discovered the wheel half holding the bearing race was cracking. It had cracked over 180 degrees around the opening, which eventually could have (led) to a serious accident.”

When technicians began to “flip” the tire to even out the wear, they found a loose bearing race. The wheel crack was then found, having progressed more than 180 degrees around the axle hole. Provided wheel p/ns are 199-64 and/or 40-40A.

Part Total Time: 2200.0 hours.

Diamond DA-20

Broken Horizontal Stabilizer Bolts

The aircraft returned from a flight with both horizontal stabilizer mount bolts broken (p/n AN3-11A). Technicians removed the rudder and horizontal stabilizer to inspect

Broken Horizontal Stabilizer Bolts


the entire area, replacing the aft mount plate and forward mount bracket, along with all new bolts, washers and nuts. Other DA-20 aircraft we inspected and similar hardware was replaced. No other issues were found on our aircraft. Diamond Aircraft has been briefed and is working with the NTSB.

Part Total Time: 189.9 hours.

Mooney M20J

Corroded Cowling Rivets

The aircrafts engine-cowling through-skin rivets were corroding and shearing off at the manufacturers head, as exhibited by blistering paint at the rivet locations. Inspection revealed most of the AD rivets were severely corroded because the cowlings are constructed with a hybrid composite laminate. Standard industry practice is to use corrosion-resistant fasteners such as Monel rivets through carbon graphite structure. It is unknown why aluminum rivets are used in this case.

Part Total Time: Unknown.

Piper PA-31-350

Failed Main Gear Bolt

The aircraft had a “gear unsafe light” and no “left down and locked” indication light; the gear handle would not return to neutral. The aircraft landed without incident. The technicians believe the upper bolt retaining the main gear retraction arm broke due to fatigue. This allowed the main gear actuator to bind on the upper section of the drag leg, breaking the main gear actuator ball end out of the main shaft of the actuator.

Although Piper Service Letter Number 1092 (June 15, 2005) requires the main gear retraction arms to be inspected, there is no similar requirement for the bolts (p/n AN6-17) retaining the main gear retraction arms.

Part Total Time: 24,842.9 hours.


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