A flight crew, in coordination with their maintenance, incorrectly interpreted the procedure for def...

Attributes
ACN	506130
Time
Date	200103
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rdu.airport
State Reference	NC
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-9 50
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 9000 flight time type : 7500
ASRS Report	506130
Events
Anomaly	aircraft equipment problem : less severe maintenance problem : non compliance with mel maintenance problem : improper maintenance non adherence : published procedure
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Maintenance Human Performance Company Flight Crew Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

Upon arriving at the aircraft I discovered a circuit breaker on the lower panel behind the captain's seat, which appeared to be damaged (bent). I called maintenance control and advise them of what I had found. The right heat exchanger cooling fan control circuit breaker was damaged. Maintenance control said if the circuit breaker could be pulled we could MEL the heat exchanger cooling fan. I pulled the circuit breaker, reviewed the MEL, made a logbook entry, and advised maintenance control. Maintenance control walked me through completing the logbook entries, filling out the MEL placard, and read me the dispatch deviation guide MEL item. As written. The procedure says: 'open and collar affected (left or right) heat exchanger cooling fan circuit breaker.' since I was dealing with the right heat exchanger cooling fan center circuit breaker and the instructions referred to '(left or right) heat exchanger cooling fan circuit breaker', I misinterpreted the procedure. The heat exchanger cooling fan is powered by 3 phase AC and has 3 circuit breakers for each fan. If the procedure had said '(left or right) heat exchanger cooling fan circuit breakers', I feel I would have been less likely to make this error. The damaged circuit breaker could not be collared because there were no circuit breaker collars onboard the aircraft (normally there is a supply stored with the spare light bulbs). A mechanic at our destination pointed out my error when I advised him that we needed circuit breaker collars onboard and the damaged circuit breaker needed to be collared.

Original NASA ASRS Text

Title: A FLC, IN COORDINATION WITH THEIR MAINT, INCORRECTLY INTERPRETED THE PROCEDURE FOR DEFERRING A HEAT EXCHANGER COOLING FAN THAT HAD ONE OF ITS THREE CIRCUIT BREAKERS DAMAGED.

Narrative: UPON ARRIVING AT THE ACFT I DISCOVERED A CIRCUIT BREAKER ON THE LOWER PANEL BEHIND THE CAPT'S SEAT, WHICH APPEARED TO BE DAMAGED (BENT). I CALLED MAINT CTL AND ADVISE THEM OF WHAT I HAD FOUND. THE R HEAT EXCHANGER COOLING FAN CTL CIRCUIT BREAKER WAS DAMAGED. MAINT CTL SAID IF THE CIRCUIT BREAKER COULD BE PULLED WE COULD MEL THE HEAT EXCHANGER COOLING FAN. I PULLED THE CIRCUIT BREAKER, REVIEWED THE MEL, MADE A LOGBOOK ENTRY, AND ADVISED MAINT CTL. MAINT CTL WALKED ME THROUGH COMPLETING THE LOGBOOK ENTRIES, FILLING OUT THE MEL PLACARD, AND READ ME THE DISPATCH DEVIATION GUIDE MEL ITEM. AS WRITTEN. THE PROCEDURE SAYS: 'OPEN AND COLLAR AFFECTED (L OR R) HEAT EXCHANGER COOLING FAN CIRCUIT BREAKER.' SINCE I WAS DEALING WITH THE R HEAT EXCHANGER COOLING FAN CTR CIRCUIT BREAKER AND THE INSTRUCTIONS REFERRED TO '(L OR R) HEAT EXCHANGER COOLING FAN CIRCUIT BREAKER', I MISINTERPRETED THE PROCEDURE. THE HEAT EXCHANGER COOLING FAN IS POWERED BY 3 PHASE AC AND HAS 3 CIRCUIT BREAKERS FOR EACH FAN. IF THE PROC HAD SAID '(L OR R) HEAT EXCHANGER COOLING FAN CIRCUIT BREAKERS', I FEEL I WOULD HAVE BEEN LESS LIKELY TO MAKE THIS ERROR. THE DAMAGED CIRCUIT BREAKER COULD NOT BE COLLARED BECAUSE THERE WERE NO CIRCUIT BREAKER COLLARS ONBOARD THE ACFT (NORMALLY THERE IS A SUPPLY STORED WITH THE SPARE LIGHT BULBS). A MECHANIC AT OUR DESTINATION POINTED OUT MY ERROR WHEN I ADVISED HIM THAT WE NEEDED CIRCUIT BREAKER COLLARS ONBOARD AND THE DAMAGED CIRCUIT BREAKER NEEDED TO BE COLLARED.

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.

A flight crew, in coordination with their maintenance, incorrectly interpreted the procedure for deferring a heat exchanger cooling fan that had one of its three circuit breakers damaged.