Wing flaps extended during flight with the flap handle up. Could not be retracted.

Attributes
ACN	242401
Time
Date	199305
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : stl
State Reference	MO
Altitude	msl bound lower : 6000 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : stl
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 260 flight time total : 7100 flight time type : 900
ASRS Report	242401
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : commercial pilot : atp
Experience	flight time last 90 days : 250 flight time total : 3200 flight time type : 900
ASRS Report	242519
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

As we leveled at 6000 ft the aircraft started to accelerate to cruise speed but then started to decelerate. Flaps, gear and power position was confirmed to be normal. Then the flap started to move to 20 degree position. We slowed the aircraft to flap speed and requested to return to st louis. As we were turning from downwind to base flaps extended to 35 degrees. We landed at st louis uneventfully. All flap extensions were uncommanded and uncontrollable. We would like to recommend to look into the possibilities of this happening again. We do believe this could have been easily a fatal accident if this was to happen during the critical phase of the flight. Supplemental information from acn 242519: at first, flap and gear indicated up and locked, then flaps extended to 20 degrees. We requested vectors to stl and slowed to flap speeds. On downwind to runway 12R at stl flaps extended to 35 degrees. If this had occurred during takeoff or landing the results could have been fatal. Recommend possible checklist change to include emergency gear and flap retraction procedures, and possible system safeguards to prevent this from occurring again. Callback conversation with reporter revealed the following information: reporter said that a valve, probably the flap control valve, was found to be leaking and the cause of the uncommanded wing flap extension. The flaps could not be retracted at any time, even after landing. Reporter's recollection of flap position during the entire flight are hazy but it seems that the flaps extended in stages. At one time, they were able to maintain 3000 ft for a period. Full flaps are 45 degrees on this airplane. He only remembers the flaps getting to 35 degrees. He had no trouble making the airport but is concerned that if this had happened after takeoff on a hot day it would have been catastrophic. He said he was told that this has happened a number of times on this aircraft.

Original NASA ASRS Text

Title: WING FLAPS EXTENDED DURING FLT WITH THE FLAP HANDLE UP. COULD NOT BE RETRACTED.

Narrative: AS WE LEVELED AT 6000 FT THE ACFT STARTED TO ACCELERATE TO CRUISE SPD BUT THEN STARTED TO DECELERATE. FLAPS, GEAR AND PWR POS WAS CONFIRMED TO BE NORMAL. THEN THE FLAP STARTED TO MOVE TO 20 DEG POS. WE SLOWED THE ACFT TO FLAP SPD AND REQUESTED TO RETURN TO ST LOUIS. AS WE WERE TURNING FROM DOWNWIND TO BASE FLAPS EXTENDED TO 35 DEGS. WE LANDED AT ST LOUIS UNEVENTFULLY. ALL FLAP EXTENSIONS WERE UNCOMMANDED AND UNCTLABLE. WE WOULD LIKE TO RECOMMEND TO LOOK INTO THE POSSIBILITIES OF THIS HAPPENING AGAIN. WE DO BELIEVE THIS COULD HAVE BEEN EASILY A FATAL ACCIDENT IF THIS WAS TO HAPPEN DURING THE CRITICAL PHASE OF THE FLT. SUPPLEMENTAL INFO FROM ACN 242519: AT FIRST, FLAP AND GEAR INDICATED UP AND LOCKED, THEN FLAPS EXTENDED TO 20 DEGS. WE REQUESTED VECTORS TO STL AND SLOWED TO FLAP SPDS. ON DOWNWIND TO RWY 12R AT STL FLAPS EXTENDED TO 35 DEGS. IF THIS HAD OCCURRED DURING TKOF OR LNDG THE RESULTS COULD HAVE BEEN FATAL. RECOMMEND POSSIBLE CHKLIST CHANGE TO INCLUDE EMER GEAR AND FLAP RETRACTION PROCS, AND POSSIBLE SYS SAFEGUARDS TO PREVENT THIS FROM OCCURRING AGAIN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID THAT A VALVE, PROBABLY THE FLAP CTL VALVE, WAS FOUND TO BE LEAKING AND THE CAUSE OF THE UNCOMMANDED WING FLAP EXTENSION. THE FLAPS COULD NOT BE RETRACTED AT ANY TIME, EVEN AFTER LNDG. RPTR'S RECOLLECTION OF FLAP POS DURING THE ENTIRE FLT ARE HAZY BUT IT SEEMS THAT THE FLAPS EXTENDED IN STAGES. AT ONE TIME, THEY WERE ABLE TO MAINTAIN 3000 FT FOR A PERIOD. FULL FLAPS ARE 45 DEGS ON THIS AIRPLANE. HE ONLY REMEMBERS THE FLAPS GETTING TO 35 DEGS. HE HAD NO TROUBLE MAKING THE ARPT BUT IS CONCERNED THAT IF THIS HAD HAPPENED AFTER TKOF ON A HOT DAY IT WOULD HAVE BEEN CATASTROPHIC. HE SAID HE WAS TOLD THAT THIS HAS HAPPENED A NUMBER OF TIMES ON THIS ACFT.

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.