MD88 lost primary heading display during high altitude cruise resulting in flight crew requesting a ...

Attributes
ACN	268374
Time
Date	199404
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : atl tracon : cof
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 5000 flight time type : 1000
ASRS Report	268374
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Flying at FL330, copilot flying noticed pfd go out. I looked at IRU's saw fault light tried to realign (can't do in flight). Ended up with no heading display. Got a no gyro approach to ATC 1400 ft overcast 8 mi visibility -- no problem. Might have strayed off course a little, but did advise ZTL that we had heading problems. Did not declare an emergency. The full chain of events is not exactly clear to either of us - - which lights came on first might have been pilot problem. (But we did have some initial problem that still has not been explained!)

Original NASA ASRS Text

Title: MD88 LOST PRIMARY HDG DISPLAY DURING HIGH ALT CRUISE RESULTING IN FLC REQUESTING A NO GYRO APCH.

Narrative: FLYING AT FL330, COPLT FLYING NOTICED PFD GO OUT. I LOOKED AT IRU'S SAW FAULT LIGHT TRIED TO REALIGN (CAN'T DO IN FLT). ENDED UP WITH NO HDG DISPLAY. GOT A NO GYRO APCH TO ATC 1400 FT OVCST 8 MI VISIBILITY -- NO PROB. MIGHT HAVE STRAYED OFF COURSE A LITTLE, BUT DID ADVISE ZTL THAT WE HAD HDG PROBS. DID NOT DECLARE AN EMER. THE FULL CHAIN OF EVENTS IS NOT EXACTLY CLR TO EITHER OF US - - WHICH LIGHTS CAME ON FIRST MIGHT HAVE BEEN PLT PROB. (BUT WE DID HAVE SOME INITIAL PROB THAT STILL HAS NOT BEEN EXPLAINED!)

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.

MD88 lost primary heading display during high altitude cruise resulting in flight crew requesting a no gyro approach.