Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
General None Reported / Taken
Chart Or Publication; Procedure; Weather
EGLL RWY 27R; stable approach to 250 feet AGL. Due wind gusts: at 250 feet AGL a loss of 8 kts airspeed with corresponding pitch attitude change. Auto-throttle engaged and system unable to rapidly correct deteriorating airspeed. Aiding the Auto-throttle system; I initially manually applied considerable power. Subsequent total loss of 12 - 14 kts at 150 feet AGL. Pushed throttles up to TOGA and pressed TOGA switch. Preformed successful manual go-around followed by auto-pilot engaged at 900 feet AGL. Engaged LNAV and VNAV.Missed approach procedures: First Officer advised me that a 185 kt speed limit (in a turn) may have been exceeded. I am unaware of speed exceedance during the 'turning portion' of this missed approach. Accelerated to clean maneuver speed during straight (non-turning) portion of this event. I could not find the initial (185kts) missed approach turning speed assignment on EGLL chart 11-4.  This event bordered on Low Level windshear.
A B777 Captain is advised by his First Officer that a 185 kt speed limit (in a turn) may have been exceeded during a missed approach at EGLL due windshear. This limit cannot be found anywhere on the 11-4 Approach chart.