DC-10 30
Maintenance Airframe; Maintenance Avionics; Maintenance Powerplant
Maintenance Technician 32
Workload; Troubleshooting; Situational Awareness; Distraction; Communication Breakdown; Time Pressure
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Logbook Entry; Human Factors; Aircraft
When the aircraft arrived; I went to flight deck to debrief crew while my partner performed post flight walk around. Crew reported all three engines remained at Flight Idle until shutdown. Note: At this time my partner reported panel missing at # 1 forward fuel boost pump and an Engineering Authorization (E.A.) was initiated. Upon visual inspection of flight deck I found 'Eng Grd/Flt Idle Cont' Circuit Breaker (C/B) (B1-1270) open [popped]. At this point I conferred with Maintenance Control/Engine group with my findings; and generated DC-10 Maintenance Manual (MM) 73-20-03-2 and DC-10 Systems Schematic Manual (SSM) 73-00-0; Page 101 for Troubleshooting Procedures. In Accordance With (IAW) DC-10 SSM 73-00-0; disconnected # 1 Eng Flt/Grd [Ground] Idle Solenoid Cannon plug to isolate malfunctioned solenoid. When attempting to close Eng Grd/Flt Idle Control C/B; the C/B continued to pop. I then disconnected # 3 Engine Flt/Grd Idle Solenoid Cannon plug to isolate it. I then was able to successfully close the Eng Grd/Flt Idle Cont. C/B. IAW DC-10 MM 73-20-03-2; I secured # 1 Engine Flt/Grd Idle Solenoid Cannon plug and verified audible click of solenoid when energized. C/B remained closed. When attempting to verify # 3 Engine solenoid by re-securing Cannon plug; the 'Eng Grd/Flt Idle Cont C/B popped. At this time I determined # 3 Engine Grd/ Flt Idle Solenoid to be bad. I conferred findings with Maintenance Control Engine group and agreed to MEL # 3 Engine IAW MEL 73-21-01-01. I then complied with MEL MAINTENANCE PROCEDURES. At engine start; flight crew confirmed Engine # 3 started in Flight Idle and # 1 and # 2 engines started in normal GRD Idle. Multiple events occurred and there were many details that needed attention; in addition to several interested parties wanting answers at the same time. I complied with required maintenance procedures; but failed to include description/explanation in the aircraft logbook. Taking one step at a time would assure all pertinent information is included in the logbook despite the pressing Estimated Time of Departure (ETD).
Reporter stated he was informed the next morning from one of their Maintenance Controllers that he had not explained in the logbook; or entered in their maintenance computer; how he arrived at determining the cause of the Circuit Breaker (C/B) popping to justify deferring # 3 Engine's Main Engine Control (MEC) GRD/Flt Idle solenoid. What was frustrating; after receiving that call; was the fact that the previous night after he had arrived home from swing shift; he started thinking he should have added more information into their maintenance computer and probably ought to go back to the airport; but he was quite tired and decided to go to bed.Reporter stated there is only one 'Eng GRD/FLT Idle Control' Circuit Breaker located in the flight deck at the Overhead Panel. The C/B will default all three engines to the Flight Idle power position if the C/B opens (pops). Each engine has a Ground (GRD)/Flight (FLT) Idle solenoid installed with four screws on the Main Engine Control (MEC) fuel control; a Cannon plug connects to the solenoid.
A Lead Mechanic was informed he had not provided enough information in the logbook and maintenance computer to explain the cause of an 'Eng Grd/Flt Idle Cont' Circuit Breaker (C/B) to open (pop) on a DC-10 aircraft and justify deferring # 3 Engine's Main Engine Control (MEC) GRD/Flt Idle solenoid. All three engines had defaulted to the Flight Idle mode on landing.