B737 flight observed leading edge devices extend while climbing to altitude.

Attributes
ACN	583953
Time
Date	200306
Day	Mon
Local Time Of Day	0001 To 0600
Place
Locale Reference	navaid : tth.vortac
State Reference	IN
Altitude	msl single value : 31000
Environment
Flight Conditions	IMC
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
ASRS Report	583953
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : le transit light other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated flight crew : overcame equipment problem
Consequence	other other other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Climbing through FL310 in IMC conditions with the autoplt on, the aircraft unexpectedly began to vibrate. I immediately noticed the red speed tape on the airspeed indicator indicating a flap overspd. As PF, I immediately took control of the aircraft and disengaged the autoplt. 1 second later, the amber leading edge device in-transit indicator illuminated. The captain immediately restowed the handle to the 0 (zero) position. Maintenance was notified in-flight and with all system and aircraft handling qualities normal, in addition to a cabin report from the purser that everything was normal, we continued to tpa. On arrival, all flight controls operated normally. Maintenance met us on arrival and inspected the aircraft. This was our last flight of the day. While working the radar yesterday during the climb phase, I may have 'touched' the flap lever as I moved my hand from the radar control unit. However, during taxi-in, I tried to duplicate this potential theory and nearly broke my watchband and the handle did not move at all from the down position. This morning, we were assigned to the same aircraft for flight on a tpa-iad segment. Now performing PNF duties, I operated the flaps on departure and they felt fine. However, on taxi-in, about 90 seconds after the flaps were retracted to the up position, the captain said, 'look at the handle now!' they had popped up to a position between zero and one. This was the event that may explain what happened on the previous flight. If the flap handle had the same malfunction yesterday that the captain and I just witnessed, the flaps would have initiated a sequence to the 1 position with just the slightest brush of the handle. The flaps will move to 1 at a point between up and 1, not only in 1 or even close to 1. The captain directed me to notify maintenance to meet us at the gate. I debriefed maintenance and the aircraft was removed from service. Although it may appear that the cause was an irregularity perhaps in the interim, we could change the after takeoff checklist to read 'flaps-up/detent'...just like the before takeoff checklist.

Original NASA ASRS Text

Title: B737 FLT OBSERVED LEADING EDGE DEVICES EXTEND WHILE CLBING TO ALT.

Narrative: CLBING THROUGH FL310 IN IMC CONDITIONS WITH THE AUTOPLT ON, THE ACFT UNEXPECTEDLY BEGAN TO VIBRATE. I IMMEDIATELY NOTICED THE RED SPD TAPE ON THE AIRSPD INDICATOR INDICATING A FLAP OVERSPD. AS PF, I IMMEDIATELY TOOK CTL OF THE ACFT AND DISENGAGED THE AUTOPLT. 1 SECOND LATER, THE AMBER LEADING EDGE DEVICE IN-TRANSIT INDICATOR ILLUMINATED. THE CAPT IMMEDIATELY RESTOWED THE HANDLE TO THE 0 (ZERO) POS. MAINT WAS NOTIFIED INFLT AND WITH ALL SYS AND ACFT HANDLING QUALITIES NORMAL, IN ADDITION TO A CABIN RPT FROM THE PURSER THAT EVERYTHING WAS NORMAL, WE CONTINUED TO TPA. ON ARR, ALL FLT CTLS OPERATED NORMALLY. MAINT MET US ON ARR AND INSPECTED THE ACFT. THIS WAS OUR LAST FLT OF THE DAY. WHILE WORKING THE RADAR YESTERDAY DURING THE CLB PHASE, I MAY HAVE 'TOUCHED' THE FLAP LEVER AS I MOVED MY HAND FROM THE RADAR CTL UNIT. HOWEVER, DURING TAXI-IN, I TRIED TO DUPLICATE THIS POTENTIAL THEORY AND NEARLY BROKE MY WATCHBAND AND THE HANDLE DID NOT MOVE AT ALL FROM THE DOWN POS. THIS MORNING, WE WERE ASSIGNED TO THE SAME ACFT FOR FLT ON A TPA-IAD SEGMENT. NOW PERFORMING PNF DUTIES, I OPERATED THE FLAPS ON DEP AND THEY FELT FINE. HOWEVER, ON TAXI-IN, ABOUT 90 SECONDS AFTER THE FLAPS WERE RETRACTED TO THE UP POS, THE CAPT SAID, 'LOOK AT THE HANDLE NOW!' THEY HAD POPPED UP TO A POS BTWN ZERO AND ONE. THIS WAS THE EVENT THAT MAY EXPLAIN WHAT HAPPENED ON THE PREVIOUS FLT. IF THE FLAP HANDLE HAD THE SAME MALFUNCTION YESTERDAY THAT THE CAPT AND I JUST WITNESSED, THE FLAPS WOULD HAVE INITIATED A SEQUENCE TO THE 1 POS WITH JUST THE SLIGHTEST BRUSH OF THE HANDLE. THE FLAPS WILL MOVE TO 1 AT A POINT BTWN UP AND 1, NOT ONLY IN 1 OR EVEN CLOSE TO 1. THE CAPT DIRECTED ME TO NOTIFY MAINT TO MEET US AT THE GATE. I DEBRIEFED MAINT AND THE ACFT WAS REMOVED FROM SVC. ALTHOUGH IT MAY APPEAR THAT THE CAUSE WAS AN IRREGULARITY PERHAPS IN THE INTERIM, WE COULD CHANGE THE AFTER TKOF CHKLIST TO READ 'FLAPS-UP/DETENT'...JUST LIKE THE BEFORE TKOF CHKLIST.

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.