Narrative:

On a scheduled flight from phx to ind at FL370, on J-80 after passing hll. The main dist circuit breaker on #1 generator bus panel opened. This power interruption caused the loss of all captain's flight instruments, FMC's radar, TCASII, ACARS, and many partial system. The circuit breaker was reset and system returned. 30 mins later, the circuit breaker opened again. Same failures, which included autoplt. There were no emergency checklists for this particular problem. No deviations and ATC was advised both times. Due to the amount of failed items, the circuit breaker was reset. This again restored the system. 10 min later, an adjacent circuit breaker, #1 transfer circuit breaker opened. The same system all failed--autoplt, captain's instruments, radar, TCASII, ACARS, autothrottles, yaw damper, FMC's, etc. ATC was advised. ATC asked for a turn direct cap and a descent to FL290. A descent was started by the first officer, he had the only working instruments, but the pressure control was inoperative. The cabin altitude warning horn sounded when the cabin exceeded 10000 ft. The aircraft was leveled off to control the pressure and manual pressurization was used to control the cabin pressure. ATC asked if we would make the FL290 altitude at cap. I advised them I was having problems with the pressurization and needed vectors to ind and a gradual descent below FL180. I declared an emergency to avoid any more ATC problems. The descent and landing at ind were completed normally. A 2 man crew is very busy when an aircraft problem is encountered. Compound this with a major loss of navigation and flight system and throw in some ATC restrictions and there is a chance for a major error. When ATC is advised of a problem, they should make sure, ask, get the fact, and help. Do not give altitude restrictions until the crew has defined the problem. Working together is very important. We crews count on ATC to help when things aren't normal. We will do anything to help ATC when we are able, but with the new, heavily computer dependent act, the loss of 1 NAVAID or computer can cause big position problems. The more or bigger the problem gets, the more distracted the crew becomes. We all have to learn how much help a 2 man crew needs when they start to have problems.

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Original NASA ASRS Text

Title: REPEATED LOSS OF ESSENTIAL FLT INSTS DUE TO REPETITIVE OPENING OF MAIN CTL CIRCUIT BREAKERS INDUCES PIC OF AIR CARRIER MLG TO DECLARE AN EMER.

Narrative: ON A SCHEDULED FLT FROM PHX TO IND AT FL370, ON J-80 AFTER PASSING HLL. THE MAIN DIST CIRCUIT BREAKER ON #1 GENERATOR BUS PANEL OPENED. THIS PWR INTERRUPTION CAUSED THE LOSS OF ALL CAPT'S FLT INSTS, FMC'S RADAR, TCASII, ACARS, AND MANY PARTIAL SYS. THE CIRCUIT BREAKER WAS RESET AND SYS RETURNED. 30 MINS LATER, THE CIRCUIT BREAKER OPENED AGAIN. SAME FAILURES, WHICH INCLUDED AUTOPLT. THERE WERE NO EMER CHKLISTS FOR THIS PARTICULAR PROBLEM. NO DEVS AND ATC WAS ADVISED BOTH TIMES. DUE TO THE AMOUNT OF FAILED ITEMS, THE CIRCUIT BREAKER WAS RESET. THIS AGAIN RESTORED THE SYS. 10 MIN LATER, AN ADJACENT CIRCUIT BREAKER, #1 TRANSFER CIRCUIT BREAKER OPENED. THE SAME SYS ALL FAILED--AUTOPLT, CAPT'S INSTS, RADAR, TCASII, ACARS, AUTOTHROTTLES, YAW DAMPER, FMC'S, ETC. ATC WAS ADVISED. ATC ASKED FOR A TURN DIRECT CAP AND A DSCNT TO FL290. A DSCNT WAS STARTED BY THE FO, HE HAD THE ONLY WORKING INSTS, BUT THE PRESSURE CTL WAS INOP. THE CABIN ALT WARNING HORN SOUNDED WHEN THE CABIN EXCEEDED 10000 FT. THE ACFT WAS LEVELED OFF TO CTL THE PRESSURE AND MANUAL PRESSURIZATION WAS USED TO CTL THE CABIN PRESSURE. ATC ASKED IF WE WOULD MAKE THE FL290 ALT AT CAP. I ADVISED THEM I WAS HAVING PROBLEMS WITH THE PRESSURIZATION AND NEEDED VECTORS TO IND AND A GRADUAL DSCNT BELOW FL180. I DECLARED AN EMER TO AVOID ANY MORE ATC PROBLEMS. THE DSCNT AND LNDG AT IND WERE COMPLETED NORMALLY. A 2 MAN CREW IS VERY BUSY WHEN AN ACFT PROBLEM IS ENCOUNTERED. COMPOUND THIS WITH A MAJOR LOSS OF NAV AND FLT SYS AND THROW IN SOME ATC RESTRICTIONS AND THERE IS A CHANCE FOR A MAJOR ERROR. WHEN ATC IS ADVISED OF A PROBLEM, THEY SHOULD MAKE SURE, ASK, GET THE FACT, AND HELP. DO NOT GIVE ALT RESTRICTIONS UNTIL THE CREW HAS DEFINED THE PROBLEM. WORKING TOGETHER IS VERY IMPORTANT. WE CREWS COUNT ON ATC TO HELP WHEN THINGS AREN'T NORMAL. WE WILL DO ANYTHING TO HELP ATC WHEN WE ARE ABLE, BUT WITH THE NEW, HEAVILY COMPUTER DEPENDENT ACT, THE LOSS OF 1 NAVAID OR COMPUTER CAN CAUSE BIG POS PROBLEMS. THE MORE OR BIGGER THE PROBLEM GETS, THE MORE DISTRACTED THE CREW BECOMES. WE ALL HAVE TO LEARN HOW MUCH HELP A 2 MAN CREW NEEDS WHEN THEY START TO HAVE PROBLEMS.

Data retrieved from NASA's ASRS site as of July 2007 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.