Pilot reports during application of speed brake on descent; speed brake handle would not move past t...

Attributes
ACN	800907
Time
Date	200808
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzzz.airport
State Reference	FO
Altitude	msl single value : 31000
Aircraft 1
Controlling Facilities	artcc : zzzz.artcc
Operator	common carrier : air carrier
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 300 flight time total : 20000 flight time type : 5000
ASRS Report	800907
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

On application of speed brakes on descent; speed brake handle became very hard to move past 1/3 point of travel and would not move past 1/2 point. No EICAS message displayed. First officer pulled up flight control screen and noticed that only left hand wing panels deployed. Aircraft yawed slightly to left -- autoplt corrected with heading selected. Captain slowly retracted all panels and was able to get back system to clean configuration for landing. Maintenance screen during malfunction on synoptic display showed left spoiler panels to 25 degrees and right panels showed 1 degree. Notified home maintenance via HF. Captain did not arm spoilers for landing. Runway data indicated sufficient distance for landing on runway 25R. Landing was not a factor; but used autobrakes 4 position due to longer runway distance required. Notified station maintenance on ACARS report and in person after landing. Ground spoilers worked ok when thrust reversers deployed during landing roll as part of automatic system deployment.

Original NASA ASRS Text

Title: PLT RPTS DURING APPLICATION OF SPEED BRAKE ON DSCNT; SPEED BRAKE HANDLE WOULD NOT MOVE PAST THE ONE HALF POINT ON THE B747-400 ACFT. NO EICAS MESSAGE DISPLAYED. ONLY L WING PANELS DEPLOYED.

Narrative: ON APPLICATION OF SPEED BRAKES ON DSCNT; SPEED BRAKE HANDLE BECAME VERY HARD TO MOVE PAST 1/3 POINT OF TRAVEL AND WOULD NOT MOVE PAST 1/2 POINT. NO EICAS MSG DISPLAYED. FO PULLED UP FLT CTL SCREEN AND NOTICED THAT ONLY L HAND WING PANELS DEPLOYED. ACFT YAWED SLIGHTLY TO L -- AUTOPLT CORRECTED WITH HDG SELECTED. CAPT SLOWLY RETRACTED ALL PANELS AND WAS ABLE TO GET BACK SYSTEM TO CLEAN CONFIGURATION FOR LNDG. MAINT SCREEN DURING MALFUNCTION ON SYNOPTIC DISPLAY SHOWED L SPOILER PANELS TO 25 DEGS AND R PANELS SHOWED 1 DEG. NOTIFIED HOME MAINT VIA HF. CAPT DID NOT ARM SPOILERS FOR LNDG. RWY DATA INDICATED SUFFICIENT DISTANCE FOR LNDG ON RWY 25R. LNDG WAS NOT A FACTOR; BUT USED AUTOBRAKES 4 POS DUE TO LONGER RWY DISTANCE REQUIRED. NOTIFIED STATION MAINT ON ACARS RPT AND IN PERSON AFTER LNDG. GND SPOILERS WORKED OK WHEN THRUST REVERSERS DEPLOYED DURING LNDG ROLL AS PART OF AUTOMATIC SYSTEM DEPLOYMENT.

Data retrieved from NASA's ASRS site as of May 2009 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.

Pilot reports during application of speed brake on descent; speed brake handle would not move past the one half point on the B747-400 aircraft. No EICAS message displayed. Only left wing panels deployed.