37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1064108 |
Time | |
Date | 201301 |
Local Time Of Day | 1801-2400 |
Place | |
Locale Reference | ZZZZ.Tower |
State Reference | US |
Environment | |
Light | Night |
Aircraft 1 | |
Make Model Name | MD-11 |
Flight Phase | Takeoff |
Flight Plan | IFR |
Component | |
Aircraft Component | Electrical Distribution |
Person 1 | |
Function | Pilot Flying First Officer |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Person 2 | |
Function | Captain Pilot Flying |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Events | |
Anomaly | Aircraft Equipment Problem Critical |
Narrative:
Prior leg was operated in this aircraft. I was PF for the 1st leg. Upon liftoff we got a master caution for a level 1 'AC tie 1 off' alert. All buses were powered; however idg 1 was supplying AC1 and leac buses directly instead of through tied bus. No real problem as everything was working. Uneventful landing and captain wrote up problem and maint. Deferred the number 1 idg and did a ground reset of the number 1 AC bus tie. After a normal start and disconnect of the number 1 idg; we got a epgs level 1 fault that required maintenance to come up and reset the ecu. Normal taxi out with all indications as stated in the MEL. Upon lift off; AC tie 1 immediately opened and we lost power to leac and AC1 buses. Du's auto reconfigured with emergency power but acted erratically. Too many level 1's to count. Captain transferred flight control to me. I continued a normal takeoff profile and called for the after takeoff checklist which the captain accomplished. Departure was complaining that our transponder wasn't on; we explained we had an electrical problem and would get back to them. Captain began to work through checklist and I assumed radios. Switched to transponder number 2 and that solved one problem. I continued to climb per ATC instructions. Climbing through the lower fl's we determined that while we had some electrical issues; the plane was stable and we could push on to destination. The air driven generator was deployed to provide battery charging so we wouldn't lose the leac. Background lighting on most switches and displays was inop and that added a level of difficulty; always having to shine a light to see what you were doing. Even though the air driven generator was deployed and it seemed we had stable power; we kept getting nuisance alerts as though there were some other problems we weren't seeing. Random 'engine ignition not armed' and 'IRU auxiliary on battery' and 'IRU battery low' to name a few. On the ILS at approximately 1;000 feet AGL; the auto pilot and auto throttles both disconnected and we received a momentary stick shaker (we were easily 10 knots above the foot). Continued approach and had a normal landing...until touchdown. The entire cockpit went dark; no communication; all du's blank; and no lights. Just prior to reaching the highspeed toward our ramp; the captains equipment powered by the leac came back on line. The electrical synoptic showed the number 1 AC tie had suddenly closed. Everything on my side remained off. I couldn't even use the number 1 radio because my audio panel was dead. Did the after landing checklist as best we could. When ramp hooked up ground power; everything on my side returned; along with numerous new level 1 alerts. I can see where maintenance thought the number 1 idg was causing the bus tie problems; but in hind sight and seeing the way things worked after we took off with it disconnected; I think there is an issue with the bus tie circuitry or some problem with the number 1 AC bus.
Original NASA ASRS Text
Title: MD11 flight crew experience a level 1 'AC Tie 1 off' alert on the first flight with this aircraft. Maintenance believes the problem is with the number one IDG and elects to defer the repair requiring the crew to disconnect the IDG prior to takeoff. Upon lift off numerous electrical anomalies are noted which the crew is able to deal with to some degree and continue to destination. During approach both auto thrust and autopilot disengage and upon landing all electrical power is lost.
Narrative: Prior leg was operated in this aircraft. I was PF for the 1st leg. Upon liftoff we got a master caution for a level 1 'AC Tie 1 Off' alert. All buses were powered; however IDG 1 was supplying AC1 and LEAC buses directly instead of through tied bus. No real problem as everything was working. Uneventful landing and Captain wrote up problem and maint. deferred the Number 1 IDG and did a ground reset of the Number 1 AC bus tie. After a normal start and disconnect of the Number 1 IDG; we got a EPGS level 1 fault that required Maintenance to come up and reset the ECU. Normal taxi out with all indications as stated in the MEL. Upon lift off; AC Tie 1 immediately opened and we lost power to LEAC and AC1 buses. DU's auto reconfigured with emergency power but acted erratically. Too many level 1's to count. Captain transferred flight control to me. I continued a normal takeoff profile and called for the after takeoff checklist which the captain accomplished. Departure was complaining that our transponder wasn't on; we explained we had an electrical problem and would get back to them. Captain began to work through checklist and I assumed radios. Switched to Transponder Number 2 and that solved one problem. I continued to climb per ATC instructions. Climbing through the lower FL's we determined that while we had some electrical issues; the plane was stable and we could push on to destination. The ADG was deployed to provide battery charging so we wouldn't lose the LEAC. Background lighting on most switches and displays was inop and that added a level of difficulty; always having to shine a light to see what you were doing. Even though the ADG was deployed and it seemed we had stable power; we kept getting nuisance alerts as though there were some other problems we weren't seeing. Random 'engine ignition not armed' and 'IRU AUX on battery' and 'IRU battery low' to name a few. On the ILS at approximately 1;000 feet AGL; the auto pilot and auto throttles both disconnected and we received a momentary stick shaker (we were easily 10 knots above the foot). Continued approach and had a normal landing...until touchdown. The entire cockpit went dark; no communication; all DU's blank; and no lights. Just prior to reaching the highspeed toward our ramp; the Captains equipment powered by the LEAC came back on line. The electrical synoptic showed the Number 1 AC tie had suddenly closed. Everything on my side remained off. I couldn't even use the Number 1 radio because my audio panel was dead. Did the after landing checklist as best we could. When ramp hooked up ground power; everything on my side returned; along with numerous new level 1 alerts. I can see where maintenance thought the Number 1 IDG was causing the bus tie problems; but in hind sight and seeing the way things worked after we took off with it disconnected; I think there is an issue with the bus tie circuitry or some problem with the Number 1 AC bus.
Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.