Enterprise1701 schrieb:Die Ermittler nennen nicht weiter definierte technische Probleme. Ist das ein Profiansatz ? Der Zugang zu der Stromversorgung geht doch aus dem Cockpit oder ?
Das ganze ist meiner Meinung nach sehr bewusst vage umschrieben.
Je mehr ich mich in die technischen Details der Stromversorgung und deren Versagen einlese, desto wahrscheinlicher halte ich ein solches Szenario.
Die NASA hat noch ne coole Seite eingerichtet:
http://asrs.arc.nasa.gov/Hier können Piloten, Techniker, Stewardessen, etc. ungewöhnliche Vorfälle anonym einreichen. Man muss natürlich beachten, dass man hier nur Vorfälle aus den USA finden wird.
Und wer sucht, der findet:
Im July 2014 gemeldet:
Approximately 25 minutes after takeoff; right generator went offline. While running checklist and prior to complying with checklist-directed disconnection of the right idg; the left generator also went offline. The 2 generator failures occurred within minutes of each other. Continued to work ecl for right generator failure; and disconnected right idg. Left and right sides of electrical system load was then assumed by the APU. An initial reset on the left generator was successful. It only lasted maybe a minute. Left generator drive shortly disconnected on its own. After collaboration with dispatch; decision was made to declare an emergency and return. Had to dump fuel. A normal landing was made. Maintenance later informed me that both drives had contaminated fluid.
Einen Untersuchungsbericht zu diesem Vorfall sucht man vergebens, weils eine Untersuchung wahrscheinlich nie gab... Ich lehne mich jetzt aus dem Fenster und behaupte, in diesem Fall war das Glück, dass die APU online ging, bevor der 2te IDG versagte. Hätte der 2te IDG vorher versagt, wären sie in ernsthafte Probleme gekommen...
Solche Problematiken werden scheinbar etwas klein gedrückt, weil die Systeme eben redundant ausgelegt sind.
Einen fast noch interessanteren Fall finde ich bei einer A320 vom März 2008. Einige Auszüge:
An A320 #2 idg failed in flight.
Enroute at FL370; we got multiple ECAM cautions that included AC bus 2 fault and gen 2 fault. Along with the ECAM cautions; we experienced the loss of the autothrust system; the sd; and the first officer's pfd; nd; and FMGC. As I had my 'screens' available;
During the event; we both scratched our heads as to what exactly was happening; as without the sd; we couldn't get a 'system' picture of our electrical state. We knew that gen 1 had not picked up anything and the 'overall picture' we were seeing was eerily similar to the emergency electrical configuration (4 screens). We spent a portion of our time on the event trying to figure a way to access the system display information to no avail. This led to some frustration and added to our task saturation.
As we approached the downwind leg to xxl; the first officer; who had already started the APU (which; by the way; would not automatically power the AC2 bus)
In addition to confirming all of our equipment losses; maintenance also noted we had lost TR2 as well.
I asked why an idg failure would take out the AC2 bus and why we didn't get the #1 gen to automatically pick up the AC2 bus. No one could offer an explanation.
He followed the aircraft's flight history for several days after this event and found no additional electrical faults occurred. He therefore assumed that the idg change solved the reoccurring idg faults.callback conversation with reporter acn 776813 revealed the following information: the reporter stated that maintenance disconnected the idg then reconnected it and started the #2 engine at the gate. The idg gen indications were normal but it would not power AC bus 2. Maintenance was unsure if the idg or generator control unit (gcu) was the problem and were unable to explain the in flight failure indications.
Auch hier habe ich keinen Untersuchungsbericht gefunden. Finde es aber toll, dass man scheinbar in der Elektrik Fehler finden kann, die sich niemand erklären kann und die nicht untersucht werden....
IDG-Fehlern wird generell verhältnismässig wenig Beachtung geschenkt, wie hier bei einem Fall vom Juli 2010, eine Boeing 777:
Shortly after departing the right generator drive light illuminated with accompanying ELEC GEN DRIVE R EICAS message. Checklist was completed successfully disconnecting the right IDG. Dispatch and Maintenance Control were contacted. Maintenance Control confirmed the IDG was disconnected and electrical system was fully powered using the APU generator. Maintenance Control indicated there was no time limit for powering the right main bus with the APU. Dispatch calculated the extra fuel burn to run the APU. Weather was good along entire route and at destination. Dumping fuel, diverting, or continuing to destination were each discussed. Dispatch indicated there were no restrictions concerning ETOPS, RVSM, or MNPS (Minimum Navigation Performance Specification). Decision was made to continue to destination while closely monitoring the APU and fuel score. Actual fuel burn was less than Dispatch's calculated burn, so flight continued to our destination.
The only reason I am filing this report is that i was notified by other 2 First Officers that apparently no operational report was filed by the Captain and a question had been raised. Since everything in relation was conducted in accordance with Company SOP and all FARs with no other complicating factors, it was my opinion that a report filed by Captain was the only report that would have been necessary.
Aus dem Jahre 2006, eine Boeing 777:
WHILE IN STABILIZED CRUISE FLT AT FL360 WE OBSERVED THE L IDG DRIVE LIGHT ILLUMINATE FOLLOWED BY AN EICAS ELECTRONIC CHKLIST FOR L GENERATOR DRIVE. WE FOLLOWED THE CHKLIST AND DISCONNECTED THE DRIVE. WHILE CONTINUING WITH THE CHKLIST WE STARTED THE APU AS INSTRUCTED AND THE APU CAME UP TO SPD AND AFTER APPROX 10 SECONDS THE APU INDICATED A FAULT AND SHUT DOWN. WE CONTACTED DISPATCH AND CONDUCTED A CONFERENCE CALL WITH MAINT REGARDING THE PROB. ALL PARTIES AGREED TO CONTINUE TO THE DEST AND ATTEMPT AN ADDITIONAL APU START DURING THE DSCNT INTO LAX.
Was auch wieder zeigt: Ist in der Elektrik erstmal der Wurm drin, funktionieren auf einmal Dinge nicht mehr, die eigentlich sollten. (APU starten)
Eine Boeing 777 im Jahre 2003:
LOST 1 ENG IDG (GENERATOR) PRIOR TO ENTERING NAT TRACKS. CHKED WITH DISPATCH AND MAINT AND DETERMINED IT WAS SAFE TO PROCEED WITH APU OPERATING NORMALLY. JUST PAST 30W, LOST OTHER ENG IDG (GENERATOR). AFTER CONTACTING DISPATCH AND MAINT, WE DETERMINED IT WAS THE SAFEST COURSE OF ACTION TO DIVERT TO BIKF (OUR NEAREST ETOPS ALT). WE DEPARTED THE ORGANIZED TRACKS IN ACCORDANCE WITH STANDARD CONTINGENCY PROCS. UPON CONTACT WITH ICELANDIC OCEANIC, WE WERE GIVEN A NEW CLRNC TO BIKF. WE LANDED WITHOUT INCIDENT. WE DECLARED AN EMER UPON DEPARTING THE TRACK, BUT CANCELLED THE EMER WITH ICELANDIC OCEANIC WHEN ESTABLISHED WITH THEM. THERE WERE NO HUMAN FACTORS WHICH WERE INVOLVED IN THE EVENT.
Und wieder: Ausfall gleich beider IDG's innerhalb kurzer Zeitspanne...
Generell ist man sich auch nicht immer sicher, was nun eine "safe operation" ist... aus dem Jahre 2002, Boeing 777:
STARTED ENGS AND R IDG DID NOT COME ON-LINE. B747 MAINT SAID TO RETURN TO GATE. B777 MAINT SAID NO NEED TO RETURN TO GATE AND ISSUED DEFER MAINT PRIOR TO TKOF. ASKED LCL ZZZ MAINT IF THE 3 PAGES OF INSTRUCTIONS HAD TO BE DONE PRIOR TO TKOF. THEY SAID NO, AND TO PUT THE MEL'ED ITEM BEHIND AND ZZZ1 MAINT WOULD HANDLE. WE THEN DEPARTED AFTER ANOTHER UNRELATED PROB WAS SECURED. THERE WERE MANY MAINT ITEMS WE FELT WERE NOT ADDRESSED. COMPANY MAINT SAID NO NEED TO RETURN TO GATE AND LCL ZZZ MAINT SAID THE SAME. WE INQUIRED ABOUT WHAT WE THOUGHT WERE LEGITIMATE CONCERNS AND MAINT LET US DOWN. IF THEY ARE NOT SURE, THEY SHOULD SAY SO AND NOT PUSH US.
nickellodeon schrieb:Das bedeutet genau was?
