Medium large transport flew with required compass inoperative.

Attributes
ACN	100200
Time
Date	198812
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : koa
State Reference	HI
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 100 flight time total : 6000 flight time type : 600
ASRS Report	100200
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : less severe non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Chart Or Publication
Air Traffic Incident	other

Narrative:

Airline's maintenance control dispatched our flight with captain's compass inoperative in accordance with their MEL which proved to be out of date. The applicable MEL requires both compass systems to be operative. Maintenance control's MEL showed 2 compass systems installed with only one required for dispatch. MEL in the airplane showed 3 compass systems installed with 2 required. Airplane actually has 2 electric compass systems and one standby compass. We assumed the third compass was the standby and we were therefore legal to depart. Four days later we learned the standby was not acceptable and that the 2 mels (maintenance control's and the one in the airplane) conflicted with each other. Solution: keep manual's up to date.

Original NASA ASRS Text

Title: MLG FLEW WITH REQUIRED COMPASS INOPERATIVE.

Narrative: AIRLINE'S MAINT CONTROL DISPATCHED OUR FLT WITH CAPT'S COMPASS INOP IN ACCORDANCE WITH THEIR MEL WHICH PROVED TO BE OUT OF DATE. THE APPLICABLE MEL REQUIRES BOTH COMPASS SYSTEMS TO BE OPERATIVE. MAINT CONTROL'S MEL SHOWED 2 COMPASS SYSTEMS INSTALLED WITH ONLY ONE REQUIRED FOR DISPATCH. MEL IN THE AIRPLANE SHOWED 3 COMPASS SYSTEMS INSTALLED WITH 2 REQUIRED. AIRPLANE ACTUALLY HAS 2 ELECTRIC COMPASS SYSTEMS AND ONE STANDBY COMPASS. WE ASSUMED THE THIRD COMPASS WAS THE STANDBY AND WE WERE THEREFORE LEGAL TO DEPART. FOUR DAYS LATER WE LEARNED THE STANDBY WAS NOT ACCEPTABLE AND THAT THE 2 MELS (MAINT CONTROL'S AND THE ONE IN THE AIRPLANE) CONFLICTED WITH EACH OTHER. SOLUTION: KEEP MANUAL'S UP TO DATE.

Data retrieved from NASA's ASRS site as of August 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.