Narrative:

On feb/xx/96 I was the captain on flight from milwaukee, wi, to des moines, ia. In flight we experienced a bleed air fail red warning light. We followed the emergency procedure and headed to dsm. I called the company maintenance department upon arrival in dsm to explain the situation and they wanted me to return the aircraft to milwaukee on a revenue flight under the provisions of the MEL for a bleed air annunciator system failure. I was not comfortable doing this because I had no way of knowing that the problem was with the annunciator system and not with the bleed air system itself. I was concerned that the aircraft had suffered a bleed air line rupture. The mechanics insisted that the MEL was applicable and I eventually talked with the director of maintenance who assured me that the problem was with the annunciator system and not an actual bleed air line rupture. I again stated that I didn't feel that the MEL was applicable and I didn't want to operate the aircraft on a revenue flight. I next received a call from my vice president of operations who again stated that the MEL applied and that he expected me to operate the flight. I again disagreed and explained my position. My boss then threatened me with termination if I did not operate the flight under the provisions of the MEL. I returned the flight to mke as instructed. The next day it was discovered that there was an actual bleed air line rupture with the aircraft. I am concerned because I was forced to operate the aircraft under the provisions of an MEL that is very questionable at best. Although the company insists that the MEL applies, I still disagree. I feel that safety was compromised because the company pushed me into operating this flight under a threat of firing. I do not believe that the MEL was intended to allow continued operation of the aircraft with a ruptured bleed air line. It turns out that we deferred an annunciator system that worked perfectly. Additionally I feel that the FAA approved MEL for this aircraft (BE1900-D) has some very ambiguous wording on several items and leaves way too much room for interpretation on certain items. The company tends to take advantage of these gray areas and operate airplanes that need to be inspected or fixed. I believe that the MEL concept is much too lenient and gives operators too much room to compromise safety. Callback conversation with reporter revealed the following information: the emergency procedure for the bleed air fail is to turn off the bleed air valve switch, which then closes 3 valves to isolate all bleeds. The warning can be generated by a bleed air leak or a faulty annunciator. The leak detector is a 1/4 inch vinyl tubing which is pressurized. When hot bleed air hits the tubing, it melts and the resultant depressurization lights the annunciator warning light. Every day the aircraft is run up with aircraft depressurized. That simulates a melted tubing and brings on the warning light. Since the bleeds were already off, any warning fault then is the annunciator. The reporter captain believes this was what the MEL refers to -- strictly an annunciator and not any failure. If, as in this case, the warning was caused by an actual bleed leak, the reporter questions how is the flight crew to know if any damage has occurred before the bleed valves are closed? To assume it is an annunciator is a set-up for a potential serious problem. Even in this incident the bleed leak was found to be a cracked pressure tubing. If that line cracked close to wiring or fuel lines, etc, and it was assumed to be an annunciator or allowed to continue flight operations, it is evident of the potential hazards. Other flts within this company which had similar warnings were ferried back for repair, whereas this one was flown, under protest by the captain, with passenger on board. Reporter's company with agreement from beech say the present MEL with bleed inoperative is safe, because once the valves are closed, no hot air can go anywhere to cause concern. However, what damage occurred before those valves were closed?

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Original NASA ASRS Text

Title: ACFT EQUIP PROB. EMER. BLEED AIR FAIL.

Narrative: ON FEB/XX/96 I WAS THE CAPT ON FLT FROM MILWAUKEE, WI, TO DES MOINES, IA. IN FLT WE EXPERIENCED A BLEED AIR FAIL RED WARNING LIGHT. WE FOLLOWED THE EMER PROC AND HEADED TO DSM. I CALLED THE COMPANY MAINT DEPT UPON ARR IN DSM TO EXPLAIN THE SIT AND THEY WANTED ME TO RETURN THE ACFT TO MILWAUKEE ON A REVENUE FLT UNDER THE PROVISIONS OF THE MEL FOR A BLEED AIR ANNUNCIATOR SYS FAILURE. I WAS NOT COMFORTABLE DOING THIS BECAUSE I HAD NO WAY OF KNOWING THAT THE PROB WAS WITH THE ANNUNCIATOR SYS AND NOT WITH THE BLEED AIR SYS ITSELF. I WAS CONCERNED THAT THE ACFT HAD SUFFERED A BLEED AIR LINE RUPTURE. THE MECHS INSISTED THAT THE MEL WAS APPLICABLE AND I EVENTUALLY TALKED WITH THE DIRECTOR OF MAINT WHO ASSURED ME THAT THE PROB WAS WITH THE ANNUNCIATOR SYS AND NOT AN ACTUAL BLEED AIR LINE RUPTURE. I AGAIN STATED THAT I DIDN'T FEEL THAT THE MEL WAS APPLICABLE AND I DIDN'T WANT TO OPERATE THE ACFT ON A REVENUE FLT. I NEXT RECEIVED A CALL FROM MY VICE PRESIDENT OF OPS WHO AGAIN STATED THAT THE MEL APPLIED AND THAT HE EXPECTED ME TO OPERATE THE FLT. I AGAIN DISAGREED AND EXPLAINED MY POS. MY BOSS THEN THREATENED ME WITH TERMINATION IF I DID NOT OPERATE THE FLT UNDER THE PROVISIONS OF THE MEL. I RETURNED THE FLT TO MKE AS INSTRUCTED. THE NEXT DAY IT WAS DISCOVERED THAT THERE WAS AN ACTUAL BLEED AIR LINE RUPTURE WITH THE ACFT. I AM CONCERNED BECAUSE I WAS FORCED TO OPERATE THE ACFT UNDER THE PROVISIONS OF AN MEL THAT IS VERY QUESTIONABLE AT BEST. ALTHOUGH THE COMPANY INSISTS THAT THE MEL APPLIES, I STILL DISAGREE. I FEEL THAT SAFETY WAS COMPROMISED BECAUSE THE COMPANY PUSHED ME INTO OPERATING THIS FLT UNDER A THREAT OF FIRING. I DO NOT BELIEVE THAT THE MEL WAS INTENDED TO ALLOW CONTINUED OP OF THE ACFT WITH A RUPTURED BLEED AIR LINE. IT TURNS OUT THAT WE DEFERRED AN ANNUNCIATOR SYS THAT WORKED PERFECTLY. ADDITIONALLY I FEEL THAT THE FAA APPROVED MEL FOR THIS ACFT (BE1900-D) HAS SOME VERY AMBIGUOUS WORDING ON SEVERAL ITEMS AND LEAVES WAY TOO MUCH ROOM FOR INTERP ON CERTAIN ITEMS. THE COMPANY TENDS TO TAKE ADVANTAGE OF THESE GRAY AREAS AND OPERATE AIRPLANES THAT NEED TO BE INSPECTED OR FIXED. I BELIEVE THAT THE MEL CONCEPT IS MUCH TOO LENIENT AND GIVES OPERATORS TOO MUCH ROOM TO COMPROMISE SAFETY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE EMER PROC FOR THE BLEED AIR FAIL IS TO TURN OFF THE BLEED AIR VALVE SWITCH, WHICH THEN CLOSES 3 VALVES TO ISOLATE ALL BLEEDS. THE WARNING CAN BE GENERATED BY A BLEED AIR LEAK OR A FAULTY ANNUNCIATOR. THE LEAK DETECTOR IS A 1/4 INCH VINYL TUBING WHICH IS PRESSURIZED. WHEN HOT BLEED AIR HITS THE TUBING, IT MELTS AND THE RESULTANT DEPRESSURIZATION LIGHTS THE ANNUNCIATOR WARNING LIGHT. EVERY DAY THE ACFT IS RUN UP WITH ACFT DEPRESSURIZED. THAT SIMULATES A MELTED TUBING AND BRINGS ON THE WARNING LIGHT. SINCE THE BLEEDS WERE ALREADY OFF, ANY WARNING FAULT THEN IS THE ANNUNCIATOR. THE RPTR CAPT BELIEVES THIS WAS WHAT THE MEL REFERS TO -- STRICTLY AN ANNUNCIATOR AND NOT ANY FAILURE. IF, AS IN THIS CASE, THE WARNING WAS CAUSED BY AN ACTUAL BLEED LEAK, THE RPTR QUESTIONS HOW IS THE FLC TO KNOW IF ANY DAMAGE HAS OCCURRED BEFORE THE BLEED VALVES ARE CLOSED? TO ASSUME IT IS AN ANNUNCIATOR IS A SET-UP FOR A POTENTIAL SERIOUS PROB. EVEN IN THIS INCIDENT THE BLEED LEAK WAS FOUND TO BE A CRACKED PRESSURE TUBING. IF THAT LINE CRACKED CLOSE TO WIRING OR FUEL LINES, ETC, AND IT WAS ASSUMED TO BE AN ANNUNCIATOR OR ALLOWED TO CONTINUE FLT OPS, IT IS EVIDENT OF THE POTENTIAL HAZARDS. OTHER FLTS WITHIN THIS COMPANY WHICH HAD SIMILAR WARNINGS WERE FERRIED BACK FOR REPAIR, WHEREAS THIS ONE WAS FLOWN, UNDER PROTEST BY THE CAPT, WITH PAX ON BOARD. RPTR'S COMPANY WITH AGREEMENT FROM BEECH SAY THE PRESENT MEL WITH BLEED INOP IS SAFE, BECAUSE ONCE THE VALVES ARE CLOSED, NO HOT AIR CAN GO ANYWHERE TO CAUSE CONCERN. HOWEVER, WHAT DAMAGE OCCURRED BEFORE THOSE VALVES WERE CLOSED?

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.