After towing an MD-80 aircraft from a hangar/line spot to a terminal gate; two Line Mechanics are informed by their Lead Mechanic the aircraft's nose gear strut was found either bent; or stuck in the Flight Mode position.
Synopsis
After towing an MD-80 aircraft from a hangar/line spot to a terminal gate; two Line Mechanics are informed by their Lead Mechanic the aircraft's nose gear strut was found either bent; or stuck in the Flight Mode position.
Narrative
I was assigned to move an MD-80 aircraft for a flight from the Hangar/Line spot to Gate. At approximate XA:15am; myself and an Aviation Maintenance Technician (AMT); first 'Locked-Out' the nose Steering By-Pass Valve and then hooked up the tow bar and tractor to the nose gear. We looked the nose gear strut over; making sure that the nose gear strut gland nut was in line with nose tire outer metal rim for the correct strut height. I then went and removed the right main gear chocks and AMT removed the left main gear chocks and he proceeded to accomplish the walk around of the aircraft; as I went to the cockpit to perform the Ground Handling Checklist (Towing section) and confirmed we had 5000 lbs of fuel in the center tank for ballast. I called Ramp Control for clearance to bring the aircraft up to the gate from the Hangar/Line spot. After I got the clearance to go; I signaled to AMT that the brakes were 'Off' and okay to move the aircraft up to gate. As we proceeded to move the aircraft up to the gate; we had to hold up behind [another] gate; prior to getting clearance to go out on Taxiway Alpha. Once we were cleared; we proceeded to gate and after we were parked at the gate; AMT Y asked me to shut off the strobe light. I moved the strobe light switch to the 'Off' position. Then I preformed the parking after towing section of the Ground Handling Checklist. By this time the gate agents had position the jet bridge on the aircraft at gate. I got off the aircraft to go inside to get my next assignment which was to move another aircraft. Just before we went out to make our next move; our Lead Mechanic asked me if we had any problems towing the MD-80 up to the gate and I said no. It seemed like any other tow job that we had done before. Then he told me that the nose gear strut is bent and I said to him are you sure; because we had no problems towing it to the gate. And that is when I went out to look at the aircraft and found that the nose strut was either bent or stuck in the Flight Mode. Also; after trying several times to wiggle the nose strut to get it to come down to the normal position and out of the Flight Mode. That was when it was determined that the nose strut was bent and the phone call was made to the maintenance office for the Manager to come look at it. After Manager looked at the nose strut it was decided to take the aircraft out of service.
Second reporter narrative
I was assigned to move an MD-80 aircraft from Hangar/Line spot to gate at XA:15am with Aviation Maintenance Technician (AMT). I first installed a nose wheel steering bypass pin and had inspected the nose strut gland nut to ensure that the nose strut was correctly inflated to the proper height. After that; [the other] Mechanic and I installed a tow bar and tractor [tug] to the nose of the aircraft's landing gear. Then I performed a pre-tow inspection as per Ground Handling Checklist. AMT removed the right main gear chocks while I removed the left main gear chocks. Afterward; AMT went up to the cockpit for the flight deck safety checks and ride brakes; minutes later he had given me a hand signal to indicate that the brakes were 'Off' and was OK to proceed behind gate. Later on AMT gave me another signal that we were clear to move. The whole operation went by smoothly except for the area in between [gates] Y3 to Y5; the road surface was bumpy. When I proceeded from Taxiway Alpha to gate; I noticed the strobe light had turned on after the ramp personnel took over my tractor and I informed AMT to turn off the strobe light; then I left gate. Later on; I was informed by the Lead Mechanic that the nose strut was bent or was stuck in Flight Mode and he (Lead Mechanic) had attempted to wiggle the nose strut several times to bring it back to a 'Normal' position; but it was of no help. The information was forwarded to the Maintenance Office and it was determined that the MD-80 aircraft was out of service.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.