Pack overheat activated taxiing out for takeoff. Flight crew unable to control, returned to gate.

Attributes
ACN	106895
Time
Date	198903
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : orf
State Reference	VA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 6700 flight time type : 3000
ASRS Report	106895
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Two engine taxi out for takeoff. Right air conditioner pack off, left air conditioner pack on. Right air pack tripped off. Duct overheat light came on. Returned to gate with smoke in cabin. Deplaned passengers through front door. Right air conditioner fan continued to run with switch off. Smoke did not stop until APU shutdown. Later found right pack valve stuck 1/2 open.

Original NASA ASRS Text

Title: PACK OVERHEAT ACTIVATED TAXIING OUT FOR TKOF. FLT CREW UNABLE TO CONTROL, RETURNED TO GATE.

Narrative: TWO ENG TAXI OUT FOR TKOF. RIGHT AIR CONDITIONER PACK OFF, LEFT AIR CONDITIONER PACK ON. RIGHT AIR PACK TRIPPED OFF. DUCT OVERHEAT LIGHT CAME ON. RETURNED TO GATE WITH SMOKE IN CABIN. DEPLANED PAXS THROUGH FRONT DOOR. RIGHT AIR CONDITIONER FAN CONTINUED TO RUN WITH SWITCH OFF. SMOKE DID NOT STOP UNTIL APU SHUTDOWN. LATER FOUND RIGHT PACK VALVE STUCK 1/2 OPEN.

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.