After taxiing a B737-300 aircraft to a hangar ramp area and shutting down engines for a C-Check wash; two Line Mechanics were informed by their Lead that the #2 engine tailpipe had a red glow. Efforts to motor engine were unsuccessful. The #2 CFM-56 engine (Fan) had seized.
Synopsis
After taxiing a B737-300 aircraft to a hangar ramp area and shutting down engines for a C-Check wash; two Line Mechanics were informed by their Lead that the #2 engine tailpipe had a red glow. Efforts to motor engine were unsuccessful. The #2 CFM-56 engine (Fan) had seized.
Narrative
I and my partner had to taxi B737-300 aircraft to the hangar from the gate for a wash at the wash rack. Before I boarded the aircraft I did a walk-around inspection of the aircraft. I climbed into the left seat and Mechanic Y into the right [seat] and we started the APU. We then called the Tower for 'Push Clearance' and proceeded with Pre-start Checks per the Checklist. After pushback; we received start clearance from the Tug Driver. At this time we performed engine start sequence.During start I did not observe any abnormal engine parameters. We then called the Tower for taxi clearance and once received; we started our taxi. Once again no abnormal engine parameters were observed. Also during taxi; no abnormal indications were observed on the flight deck such as Master Caution or Fire Warning. Upon arrival at the wash rack; I shut-down the #2 engine first; and then shut-down the #1 engine. It should be noted that there was a very strong tail wind present. We then waited for the Lead to pull us into the wash rack. The Lead pulled up and informed us the #2 engine tail pipe had a red glow. Immediately I looked at the #2 EGT and observed 520 degrees Celsius. We decided to motor #2 [engine] since we had no fire indications and EGT was not over the limits.Upon motoring of #2 engine -- no N1 rotation was observed. So this was aborted. We noticed #2 engine EGT cooling slowly so we were pulled into the wash rack. We confirmed #2 engine was seized up (fan). It was also observed some black soot in the #2 engine tail pipe. A boroscope was performed and damage to the Low Pressure (LP) turbine was found. These are the events as they happened to the best of my knowledge.
Second reporter narrative
We opened up panels for the C-Check wash. I took the 'Wash' paperwork on aircraft and checked [cabin] back doors. We did our Pre-start Checklist. Co-worker (Mechanic X) was in left seat and I was in right. We called for Pushback. After disconnect we finished Checklist and started the engines. I called for taxi clearance and we slowly taxied to the hangar. Once we were at hangar; Mechanic X shut engines down.Three to four minutes after shut-down; my Lead came up in the truck on the right side; slowed and circled the aircraft. He came back to the right side and said the #2 engine was glowing. I looked over and saw #2 EGT around 520 degrees Celsius; and #1 engine was at 290 degrees. Engaged starter to cool engine down; after a few seconds (15); my co-worker asked; 'are you turning the wrong motor?' I was looking out window at #2 engine. Disengaged Start switch. N1 (Fan) was not turning. I did note that the EGT dropped down to 420 degrees. Hooked tow bar to aircraft as engine spooled down. We were pulled into the wash rack; then tried to hand turn N1. No joy.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.