Light Sport Aircraft
Maintenance Airframe; Maintenance Powerplant
Maintenance Lead Technician 8
Situational Awareness; Time Pressure; Distraction
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Aircraft Damaged; General Maintenance Action
Aircraft; Human Factors
I signed-off a 100-Hour Inspection on a SportStar Evektor aircraft. Part of the Inspection was inspecting the brakes. The brakes on the left side were close to the wear limit so I removed the wheel to remove the brake linings so I could more easily measure the lining. The brakes were found to be in an airworthy condition so they were re-installed on the aircraft; then the wheel was re-installed. When replacing the cotter pin; the first cotter pin I attempted to use was too short so I used another. The Service Manual called for a 4X.04 [cotter pin]; the one I used was 4X.36; well at least I thought I used it. At first we thought that it had come out; but when myself and an FAA representative tried it; it did not go through the axle; so I assumed I just forgot to use a cotter pin. During the time that I put the one that was too short back and got the other one; I had a phone call and I felt rushed because the aircraft was a flight school airplane and needed to be put back on the schedule for the weekend and I assume; from all the stress; it just slipped my mind. The pilot and I took the aircraft for a Test Flight; which was also part of the Check List and everything was fine. Then; two days later; the aircraft was doing Touch and Goes and on the last take-off the pilot said that he felt a vibration; then when landed found the tire had fallen off. The wheel and nut were both found; the wheel was located in the grass just off of the runway and the nut was found on the runway. The aircraft sustained minor damage and nobody was hurt. I have NEVER had anything like this happen before and have learned a lesson from this and that is to SLOW down and double check ALL my work before I let the aircraft leave the Shop. I feel horrible about this and it will NEVER happen again.
Reporter stated there are a lot of people and a lot of aircraft with a heavy workload at their FBO. He wanted to let everyone know that he is just human and felt rushed to get the 100-hour Inspection completed. The one lesson he would take from his recent experience would be to 'NOT;' let anyone pressure him to go faster when performing maintenance; that's when mistakes are made due to that kind of distraction.
An FBO Mechanic reports a left Main Landing Gear (MLG) tire and wheel assembly had separated from a SportStar Evektor aircraft on takeoff; two days after he had completed a 100-hour Inspection.