B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Type 3005.9
Situational Awareness
Deviation - Speed All Types; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Flight Crew Executed Go Around / Missed Approach; Flight Crew Became Reoriented
Human Factors; Weather
On approach to RJAA for ILS 34L; ATIS reported surface winds (approximately) 310/24G28. Earlier; aircraft on both 34L and 34R had reported wind shear with +/-10 and +/-15 knots; respectively. This information was also on the arrival ATIS. We had an approach speed for Flap 30 of 147 with a wind correction of +15 for a reference speed of 162. Passing approximately 500 AGL; a performance increasing wind shear occurred with the IAS noted at 175; right at the flap limit speed for Flaps 30. Throttle were reduced to correct the deviation; but at no time was idle thrust selected. By 300 feet AGL; speed was approximately 165-170 and fluctuating. Passing 200 feet AGL; we were on ILS GS with PAPI showing one white and three red. We were within speed parameters for a stabilized approach and in a safe position to land. At this time the Ground Proximity Warning System (GPWS) gave several warnings of 'Too low terrain'. At this time; we verified our configuration and noted the Flaps indicated 25 degrees; but the handle was in the 30 degree detent. Without delay; we executed a go around.The following approach had similar conditions; but reactions to the expected performance-increasing wind shear resulted in airspeed deviation of no greater than 10 IAS. The resulting approach and landing were uneventful.I would have expected 'Too low Flaps' for this condition. I am not sure why we got 'Too low terrain'. Either warning would have given the same result; but we would have had more clarity on our issue with the more appropriate warning.
B737NG Captain reported executing a go-around after receiving a 'Too low terrain' alert on short final at RJAA.