B777-200 crew had a flap overspd during an encounter with windshear and go around.

Attributes
ACN	565834
Time
Date	200211
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : egll.airport
State Reference	FO
Altitude	agl single value : 100
Environment
Weather Elements	Windshear
Aircraft 1
Controlling Facilities	tower : egll.tower
Operator	common carrier : air carrier
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach landing : go around
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 155 flight time total : 10000 flight time type : 1006
ASRS Report	565834
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	inflight encounter : weather non adherence : published procedure non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : flap limit speed indication wind sheer aural warning other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : executed go around
Consequence	other other
Supplementary
Problem Areas	Weather Flight Crew Human Performance
Primary Problem	Weather

Narrative:

Airplane held at bnn for approximately 15 mins, ATIS was monitored and winds reported as gusty from 200 degrees, 23 KTS gusting to 37 KT. Decision was made to land flaps 25 degrees with autothrottles off as per fom. At approximately 100 ft on runway 27R lhr, the airspeed dropped from 157 KTS to 142 KTS and the aircraft sank to all red on the VASI. An aural windshear advisory was received simultaneously with the crew initiating a go around. The aircraft descended to below 50 ft before starting to climb. The toga switches were engaged and the captain went to firewall thrust. As soon as a positive rate of climb was established, the gear was raised. At approximately 500 ft the flaps were raised to 20 degrees. As the aircraft climbed out of the shear, the airspeed jumped significantly. The copilot noted that the airspeed was 20 KTS above flaps 20 degree speed. Flaps were raised to 15 degrees and it was noted that the airspeed was approximately 30 KTS above 15 degrees flaps speed. Power was reduced and flaps retracted aircraft then flew another approach and landed successfully on runway 27L. Logbook write was made for the flap overspd.

Original NASA ASRS Text

Title: B777-200 CREW HAD A FLAP OVERSPD DURING AN ENCOUNTER WITH WINDSHEAR AND GAR.

Narrative: AIRPLANE HELD AT BNN FOR APPROX 15 MINS, ATIS WAS MONITORED AND WINDS RPTED AS GUSTY FROM 200 DEGS, 23 KTS GUSTING TO 37 KT. DECISION WAS MADE TO LAND FLAPS 25 DEGS WITH AUTOTHROTTLES OFF AS PER FOM. AT APPROX 100 FT ON RWY 27R LHR, THE AIRSPD DROPPED FROM 157 KTS TO 142 KTS AND THE ACFT SANK TO ALL RED ON THE VASI. AN AURAL WINDSHEAR ADVISORY WAS RECEIVED SIMULTANEOUSLY WITH THE CREW INITIATING A GAR. THE ACFT DSNDED TO BELOW 50 FT BEFORE STARTING TO CLB. THE TOGA SWITCHES WERE ENGAGED AND THE CAPT WENT TO FIREWALL THRUST. AS SOON AS A POSITIVE RATE OF CLB WAS ESTABLISHED, THE GEAR WAS RAISED. AT APPROX 500 FT THE FLAPS WERE RAISED TO 20 DEGS. AS THE ACFT CLBED OUT OF THE SHEAR, THE AIRSPD JUMPED SIGNIFICANTLY. THE COPLT NOTED THAT THE AIRSPD WAS 20 KTS ABOVE FLAPS 20 DEG SPD. FLAPS WERE RAISED TO 15 DEGS AND IT WAS NOTED THAT THE AIRSPD WAS APPROX 30 KTS ABOVE 15 DEGS FLAPS SPD. PWR WAS REDUCED AND FLAPS RETRACTED ACFT THEN FLEW ANOTHER APCH AND LANDED SUCCESSFULLY ON RWY 27L. LOGBOOK WRITE WAS MADE FOR THE FLAP OVERSPD.

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.