Tail strike on landing with non standard flap setting due to a trailing edge flap disagree light.

Attributes
ACN	157058
Time
Date	199009
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : man
State Reference	FO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 50 flight time total : 10000 flight time type : 250
ASRS Report	157058
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact
Consequence	other Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Experienced trailing edge flap disagree warning with flaps at 1 degree while configuring for landing at man. Crew accomplished trailing edge flap asymmetry (flaps less than 5 degrees) procedure and continued approach, an ILS to runway 24. Speed on approach was 30 degree flap reference speed, plus 30 KTS to idle after descending below 100' afl. The attempt to flare resulted in no reduction of sink rate and a firm, but not hard, T/D followed. The tail skid warning light illuminated, indicating tail skid impact. Crew reactions were ones of surprise, as the T/D did not seem to be sufficiently hard, nor was the sink rate more than marginally greater than normal. None of the crew had previously flown a 1 degree flap landing in an aircraft, although each had flown several in the simulator. The perception of the PF was that the aircraft did not response like the simulator (the PF is a simulator instrument). A crew postmortem revealed that first officer and second officer had accomplished an incorrect procedure; i.e., they completed the trailing edge flap asymmetry procedure when the malfunction was actually a trailing edge flap disagree. Either procedure should have resulted in a safe landing, however. I question the validity of the airspeed additive recommended by the above procedure. The aircraft felt as though it had insufficient speed to flare.

Original NASA ASRS Text

Title: TAIL STRIKE ON LNDG WITH NON STANDARD FLAP SETTING DUE TO A TRAILING EDGE FLAP DISAGREE LIGHT.

Narrative: EXPERIENCED TRAILING EDGE FLAP DISAGREE WARNING WITH FLAPS AT 1 DEG WHILE CONFIGURING FOR LNDG AT MAN. CREW ACCOMPLISHED TRAILING EDGE FLAP ASYMMETRY (FLAPS LESS THAN 5 DEGS) PROC AND CONTINUED APCH, AN ILS TO RWY 24. SPD ON APCH WAS 30 DEG FLAP REF SPD, PLUS 30 KTS TO IDLE AFTER DSNDING BELOW 100' AFL. THE ATTEMPT TO FLARE RESULTED IN NO REDUCTION OF SINK RATE AND A FIRM, BUT NOT HARD, T/D FOLLOWED. THE TAIL SKID WARNING LIGHT ILLUMINATED, INDICATING TAIL SKID IMPACT. CREW REACTIONS WERE ONES OF SURPRISE, AS THE T/D DID NOT SEEM TO BE SUFFICIENTLY HARD, NOR WAS THE SINK RATE MORE THAN MARGINALLY GREATER THAN NORMAL. NONE OF THE CREW HAD PREVIOUSLY FLOWN A 1 DEG FLAP LNDG IN AN ACFT, ALTHOUGH EACH HAD FLOWN SEVERAL IN THE SIMULATOR. THE PERCEPTION OF THE PF WAS THAT THE ACFT DID NOT RESPONSE LIKE THE SIMULATOR (THE PF IS A SIMULATOR INSTR). A CREW POSTMORTEM REVEALED THAT F/O AND S/O HAD ACCOMPLISHED AN INCORRECT PROC; I.E., THEY COMPLETED THE TRAILING EDGE FLAP ASYMMETRY PROC WHEN THE MALFUNCTION WAS ACTUALLY A TRAILING EDGE FLAP DISAGREE. EITHER PROC SHOULD HAVE RESULTED IN A SAFE LNDG, HOWEVER. I QUESTION THE VALIDITY OF THE AIRSPD ADDITIVE RECOMMENDED BY THE ABOVE PROC. THE ACFT FELT AS THOUGH IT HAD INSUFFICIENT SPD TO FLARE.

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.