An air carrier widebody transport had an inadvertent slat deployment with a loss of altitude.

Attributes
ACN	245745
Time
Date	199307
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : yhz
State Reference	NF
Altitude	msl bound lower : 34000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : czqx tower : den
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : atlantic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain observation : company check pilot oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 18000
ASRS Report	245745
Person 2
Affiliation	company : air carrier
Function	flight crew : captain instruction : trainee
Qualification	pilot : atp
Experience	flight time last 90 days : 84 flight time type : 26
ASRS Report	246210
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

I am a check airman for an air carrier. I was returning to jfk from lhr with a new captain in the left seat. I noticed that the flap/slat handle and the slat stow lever seemed 'not quite right' in appearance. To assure proper stowage of the flap/slat handle, I reached over and cycled the slat stow lever (as per procedure) to assure proper stowage of the flap/slat handle. The instant I pushed the slat stow lever forward, the slats deployed and buffeting occurred. I disconnected the autoplt, leveled the wings, and added power. We lost 1000 ft but regained control when I pushed the flap/slat handle forward to seat it. We climbed back to FL350 and told gander everything was ok. I noticed that, upon retracting the slats on takeoff at lhr, the slat stow lever felt 'odd' but was satisfied of its operation at that time. I forgot about the slat stow lever. Everything about the flight seemed normal. When we were in cruise at FL350/.83 mach and in a relatively relaxed atmosphere (about 1 hour from touchdown) did I become aware of the flap/slat handle and slat stow lever appearance. As we were losing altitude, gander called and asked if we were ok. We responded that we had had a problem but everything now was under control. I suspect the whole thing lasted about 30 seconds (seemed like a lifetime of buffeting). Callback conversation with reporter revealed the following information: the reporting captain states that he lost 1000 ft in this maneuver and that czqx immediately noted this and offered assistance. The 2 position slats have a 16 second cycle from up to down and back up. The aircraft buffeted wildly during this time. The reporter took the aircraft off of the autoplt during the gyrations. The aircraft manufacturer has put in a temporary fix consisting of a latch that holds the flap/slat handle in the up/retract position. It requires 2 hands to move the handle to the slat extend position. A permanent fix is in the works that will replace the current mechanical monstrosity with an electrical switch. The reporter states that he flew a test hop on this aircraft the next day and the system worked properly. Maintenance found that the handle was not properly rigged, that there was too much tension on the flap/slat handle.

Original NASA ASRS Text

Title: AN ACR WDB HAD AN INADVERTENT SLAT DEPLOYMENT WITH A LOSS OF ALT.

Narrative: I AM A CHK AIRMAN FOR AN ACR. I WAS RETURNING TO JFK FROM LHR WITH A NEW CAPT IN THE L SEAT. I NOTICED THAT THE FLAP/SLAT HANDLE AND THE SLAT STOW LEVER SEEMED 'NOT QUITE RIGHT' IN APPEARANCE. TO ASSURE PROPER STOWAGE OF THE FLAP/SLAT HANDLE, I REACHED OVER AND CYCLED THE SLAT STOW LEVER (AS PER PROC) TO ASSURE PROPER STOWAGE OF THE FLAP/SLAT HANDLE. THE INSTANT I PUSHED THE SLAT STOW LEVER FORWARD, THE SLATS DEPLOYED AND BUFFETING OCCURRED. I DISCONNECTED THE AUTOPLT, LEVELED THE WINGS, AND ADDED PWR. WE LOST 1000 FT BUT REGAINED CTL WHEN I PUSHED THE FLAP/SLAT HANDLE FORWARD TO SEAT IT. WE CLBED BACK TO FL350 AND TOLD GANDER EVERYTHING WAS OK. I NOTICED THAT, UPON RETRACTING THE SLATS ON TKOF AT LHR, THE SLAT STOW LEVER FELT 'ODD' BUT WAS SATISFIED OF ITS OP AT THAT TIME. I FORGOT ABOUT THE SLAT STOW LEVER. EVERYTHING ABOUT THE FLT SEEMED NORMAL. WHEN WE WERE IN CRUISE AT FL350/.83 MACH AND IN A RELATIVELY RELAXED ATMOSPHERE (ABOUT 1 HR FROM TOUCHDOWN) DID I BECOME AWARE OF THE FLAP/SLAT HANDLE AND SLAT STOW LEVER APPEARANCE. AS WE WERE LOSING ALT, GANDER CALLED AND ASKED IF WE WERE OK. WE RESPONDED THAT WE HAD HAD A PROB BUT EVERYTHING NOW WAS UNDER CTL. I SUSPECT THE WHOLE THING LASTED ABOUT 30 SECONDS (SEEMED LIKE A LIFETIME OF BUFFETING). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTING CAPT STATES THAT HE LOST 1000 FT IN THIS MANEUVER AND THAT CZQX IMMEDIATELY NOTED THIS AND OFFERED ASSISTANCE. THE 2 POS SLATS HAVE A 16 SECOND CYCLE FROM UP TO DOWN AND BACK UP. THE ACFT BUFFETED WILDLY DURING THIS TIME. THE RPTR TOOK THE ACFT OFF OF THE AUTOPLT DURING THE GYRATIONS. THE ACFT MANUFACTURER HAS PUT IN A TEMPORARY FIX CONSISTING OF A LATCH THAT HOLDS THE FLAP/SLAT HANDLE IN THE UP/RETRACT POS. IT REQUIRES 2 HANDS TO MOVE THE HANDLE TO THE SLAT EXTEND POS. A PERMANENT FIX IS IN THE WORKS THAT WILL REPLACE THE CURRENT MECHANICAL MONSTROSITY WITH AN ELECTRICAL SWITCH. THE RPTR STATES THAT HE FLEW A TEST HOP ON THIS ACFT THE NEXT DAY AND THE SYS WORKED PROPERLY. MAINT FOUND THAT THE HANDLE WAS NOT PROPERLY RIGGED, THAT THERE WAS TOO MUCH TENSION ON THE FLAP/SLAT HANDLE.

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.