B-727 freighter operated with a misdiagnosis on the inoperative aft stair light warning system.

Attributes
ACN	262304
Time
Date	199401
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : roc
State Reference	NY
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mty
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground other : taxi landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 100 flight time total : 10000 flight time type : 5500
ASRS Report	262304
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other other : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

The WX in the northeast had been bitterly cold -- record low temperatures. The ramp was covered with a layer of compacted snow and ice. The 'aft airstair' unlocked light on our b- 727 had been deferred by maintenance. So, besides the normal verification from the mechanic that the stairs were up and locked, we had no indication that the stairs might be unlocked, i.e., the unlocked light was illuminated. During the pushback at ewr the mechanic saw the stairs come unlocked and fall down. The push was stopped temporarily. Because the ramp was icy, the stairs slid easily and no damage resulted. The mechanic reclosed and locked the stairs up. The push continued and we departed for roc. The flight was uneventful. After landing on runway 22 we taxied northeast on taxiway B. Ground control at roc asked us if we knew we were dragging our aft stairs. Obviously, we didn't know and immediately stopped taxiing. We called our maintenance in roc. They came out, put the stairs back up and followed us to the gate to ensure that the stairs remained up. The mechanic said he found ice on some control cables, broke them free and now 'all was well.' the captain prudently decided that additional trouble-shooting was indicated. We went into crew rest. That evening we showed to fly roc to dtw to ewr. Maintenance had found the stair operating mechanism worn. The stairs were secured up and inoperative. The 2 legs were flown uneventfully. Another fine' murphian' example.

Original NASA ASRS Text

Title: B-727 FREIGHTER OPERATED WITH A MISDIAGNOSIS ON THE INOP AFT STAIR LIGHT WARNING SYS.

Narrative: THE WX IN THE NE HAD BEEN BITTERLY COLD -- RECORD LOW TEMPS. THE RAMP WAS COVERED WITH A LAYER OF COMPACTED SNOW AND ICE. THE 'AFT AIRSTAIR' UNLOCKED LIGHT ON OUR B- 727 HAD BEEN DEFERRED BY MAINT. SO, BESIDES THE NORMAL VERIFICATION FROM THE MECH THAT THE STAIRS WERE UP AND LOCKED, WE HAD NO INDICATION THAT THE STAIRS MIGHT BE UNLOCKED, I.E., THE UNLOCKED LIGHT WAS ILLUMINATED. DURING THE PUSHBACK AT EWR THE MECH SAW THE STAIRS COME UNLOCKED AND FALL DOWN. THE PUSH WAS STOPPED TEMPORARILY. BECAUSE THE RAMP WAS ICY, THE STAIRS SLID EASILY AND NO DAMAGE RESULTED. THE MECH RECLOSED AND LOCKED THE STAIRS UP. THE PUSH CONTINUED AND WE DEPARTED FOR ROC. THE FLT WAS UNEVENTFUL. AFTER LNDG ON RWY 22 WE TAXIED NE ON TXWY B. GND CTL AT ROC ASKED US IF WE KNEW WE WERE DRAGGING OUR AFT STAIRS. OBVIOUSLY, WE DIDN'T KNOW AND IMMEDIATELY STOPPED TAXIING. WE CALLED OUR MAINT IN ROC. THEY CAME OUT, PUT THE STAIRS BACK UP AND FOLLOWED US TO THE GATE TO ENSURE THAT THE STAIRS REMAINED UP. THE MECH SAID HE FOUND ICE ON SOME CTL CABLES, BROKE THEM FREE AND NOW 'ALL WAS WELL.' THE CAPT PRUDENTLY DECIDED THAT ADDITIONAL TROUBLE-SHOOTING WAS INDICATED. WE WENT INTO CREW REST. THAT EVENING WE SHOWED TO FLY ROC TO DTW TO EWR. MAINT HAD FOUND THE STAIR OPERATING MECHANISM WORN. THE STAIRS WERE SECURED UP AND INOP. THE 2 LEGS WERE FLOWN UNEVENTFULLY. ANOTHER FINE' MURPHIAN' EXAMPLE.

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.