EMB145 crew departed with 2 conflicting MEL items which prohibited both being deferred.

Attributes
ACN	550994
Time
Date	200206
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : buf.airport
State Reference	NY
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance ground : parked
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 5300 flight time type : 550
ASRS Report	550994
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe maintenance problem : non compliance with mel maintenance problem : improper documentation non adherence : company policies non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : detected after the fact other
Consequence	other other
Factors
Maintenance	contributing factor : briefing contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : repair
Supplementary
Problem Areas	Company FAA Aircraft Flight Crew Human Performance Maintenance Human Performance
Primary Problem	Company

Narrative:

On jun/tue/02, we reported at lga report for our air carrier trip pairing of 2 round trips to buffalo, ny. We boarded our EMB145 to begin flight XXXX. On accepting the plane, I noted 2 deferrals for the plane. Generator #3 was deferred, as was the 'APU fail' caption that is displayed on our EICAS if the APU malfunctions. The 'message' was deferred because the APU was functioning normally, as were all accessories on the APU (generator, bleed valve, etc) but the caption was being displayed on our EICAS. As procedure and good judgement dictate, I referred to the MEL to check for any restrs that may be in place due to these deferrals. The MEL states 1 of the 4 engine driven generators may be inoperative, provided the APU is functioning and its generator is used to supplement the 3 engine driven generators. The MEL states that the 'APU fail' message is deferrable provided the APU is operated on the ground only. This is in disagreement to the required procedures if an engine driven generator is deferred. I doublechked the logbook, and verified that both items had been deferred by maintenance, and placarded. They were. Maintenance was called to the aircraft, and we challenged the deferrals, noting the MEL notes, and we were told that both deferrals were accurate and the aircraft was 'good to go.' I restated the MEL notes and again was told the aircraft was legal. With this, we boarded and flew to buffalo uneventfully. When we landed in buffalo, we were told we had a delay for maintenance. Unaware of any new maintenance items, I phoned our maintenance control and was told the deferrals on the aircraft were, in fact, incorrect. Contract maintenance came and fixed the 'APU fail' caption deferral, but by that time the incorrect deferral matter was a legality issue. I stated to our chief pilot that we were told in lga by maintenance that the aircraft was legal to fly with the 2 items deferred. The company is now handling the occurrence through a 'self disclosure' policy with the FAA. I feel there is a mix of items that led to this problem that led to 3 legs being flown with ultimately an incorrect deferral. (A second crew had done an rdu trip prior to our buf leg.) a mix of maintenance mishandling the deferrals, dispatch releasing the trip, a 'poor' MEL procedure for the 'APU fail' caption, and misinfo given to my crew and I all led to the occurrence. Revising the MEL procedure for the 'APU fail' caption would easily avoid an event like this recurring, APU operation should be allowed in conjunction with a deferred engine driven generator. There are other indications of proper APU operation on the EICAS, including RPM and egt. There are several other EICAS warnings and cautions that would alert the crew to improper APU function (low oil pressure, high oil temperature, generator overload, APU fire are a few). Also, the APU is controled by an electronic sequence unit that automatically shuts the APU down for certain malfunctions.

Original NASA ASRS Text

Title: EMB145 CREW DEPARTED WITH 2 CONFLICTING MEL ITEMS WHICH PROHIBITED BOTH BEING DEFERRED.

Narrative: ON JUN/TUE/02, WE RPTED AT LGA RPT FOR OUR ACR TRIP PAIRING OF 2 ROUND TRIPS TO BUFFALO, NY. WE BOARDED OUR EMB145 TO BEGIN FLT XXXX. ON ACCEPTING THE PLANE, I NOTED 2 DEFERRALS FOR THE PLANE. GENERATOR #3 WAS DEFERRED, AS WAS THE 'APU FAIL' CAPTION THAT IS DISPLAYED ON OUR EICAS IF THE APU MALFUNCTIONS. THE 'MESSAGE' WAS DEFERRED BECAUSE THE APU WAS FUNCTIONING NORMALLY, AS WERE ALL ACCESSORIES ON THE APU (GENERATOR, BLEED VALVE, ETC) BUT THE CAPTION WAS BEING DISPLAYED ON OUR EICAS. AS PROC AND GOOD JUDGEMENT DICTATE, I REFERRED TO THE MEL TO CHK FOR ANY RESTRS THAT MAY BE IN PLACE DUE TO THESE DEFERRALS. THE MEL STATES 1 OF THE 4 ENG DRIVEN GENERATORS MAY BE INOP, PROVIDED THE APU IS FUNCTIONING AND ITS GENERATOR IS USED TO SUPPLEMENT THE 3 ENG DRIVEN GENERATORS. THE MEL STATES THAT THE 'APU FAIL' MESSAGE IS DEFERRABLE PROVIDED THE APU IS OPERATED ON THE GND ONLY. THIS IS IN DISAGREEMENT TO THE REQUIRED PROCS IF AN ENG DRIVEN GENERATOR IS DEFERRED. I DOUBLECHKED THE LOGBOOK, AND VERIFIED THAT BOTH ITEMS HAD BEEN DEFERRED BY MAINT, AND PLACARDED. THEY WERE. MAINT WAS CALLED TO THE ACFT, AND WE CHALLENGED THE DEFERRALS, NOTING THE MEL NOTES, AND WE WERE TOLD THAT BOTH DEFERRALS WERE ACCURATE AND THE ACFT WAS 'GOOD TO GO.' I RESTATED THE MEL NOTES AND AGAIN WAS TOLD THE ACFT WAS LEGAL. WITH THIS, WE BOARDED AND FLEW TO BUFFALO UNEVENTFULLY. WHEN WE LANDED IN BUFFALO, WE WERE TOLD WE HAD A DELAY FOR MAINT. UNAWARE OF ANY NEW MAINT ITEMS, I PHONED OUR MAINT CTL AND WAS TOLD THE DEFERRALS ON THE ACFT WERE, IN FACT, INCORRECT. CONTRACT MAINT CAME AND FIXED THE 'APU FAIL' CAPTION DEFERRAL, BUT BY THAT TIME THE INCORRECT DEFERRAL MATTER WAS A LEGALITY ISSUE. I STATED TO OUR CHIEF PLT THAT WE WERE TOLD IN LGA BY MAINT THAT THE ACFT WAS LEGAL TO FLY WITH THE 2 ITEMS DEFERRED. THE COMPANY IS NOW HANDLING THE OCCURRENCE THROUGH A 'SELF DISCLOSURE' POLICY WITH THE FAA. I FEEL THERE IS A MIX OF ITEMS THAT LED TO THIS PROB THAT LED TO 3 LEGS BEING FLOWN WITH ULTIMATELY AN INCORRECT DEFERRAL. (A SECOND CREW HAD DONE AN RDU TRIP PRIOR TO OUR BUF LEG.) A MIX OF MAINT MISHANDLING THE DEFERRALS, DISPATCH RELEASING THE TRIP, A 'POOR' MEL PROC FOR THE 'APU FAIL' CAPTION, AND MISINFO GIVEN TO MY CREW AND I ALL LED TO THE OCCURRENCE. REVISING THE MEL PROC FOR THE 'APU FAIL' CAPTION WOULD EASILY AVOID AN EVENT LIKE THIS RECURRING, APU OP SHOULD BE ALLOWED IN CONJUNCTION WITH A DEFERRED ENG DRIVEN GENERATOR. THERE ARE OTHER INDICATIONS OF PROPER APU OP ON THE EICAS, INCLUDING RPM AND EGT. THERE ARE SEVERAL OTHER EICAS WARNINGS AND CAUTIONS THAT WOULD ALERT THE CREW TO IMPROPER APU FUNCTION (LOW OIL PRESSURE, HIGH OIL TEMP, GENERATOR OVERLOAD, APU FIRE ARE A FEW). ALSO, THE APU IS CTLED BY AN ELECTRONIC SEQUENCE UNIT THAT AUTOMATICALLY SHUTS THE APU DOWN FOR CERTAIN MALFUNCTIONS.

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.