Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter CFTT / CFIT
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Executed Go Around / Missed Approach
Weather; Human Factors
Approaching PHL for landing there were numerous storms approaching the airport from the west. Upon analyzing the radar; we decided to postpone the approach until the storms passed the field. After 20 minutes we decided to proceed to shoot the ILS 27R. Weather at the field was reported marginal VFR with thunderstorms in the vicinity. Right at 1;000 feet and stable; the Tower advised of a windshear alert. At 900 feet we received a 'windshear ahead' warning immediately followed by a 'go-around windshear ahead' warning. We immediately executed a go-around using normal go-around procedures. At 1;200 feet; the aircraft began to lose speed; buffet and sink. At that point we executed the windshear escape procedure as trained. Lowest altitude reached was 620 feet before we flew out of the shear and aircraft performance returned to normal. We advised the Tower and were vectored around to ILS 9R for a normal approach and landing. The event occurred because it was an act of God. We did everything possible to mitigate the potential effects of the weather on the approach. We delayed the approach to allow the weather to pass. We held extra speed on the approach as a precaution for shear. We discussed a plan of action and contingencies for the approach. We followed procedure when confronted with the windshear event. The only thing we could have done is possibly to wait a little longer for the weather to move away from the airport. However; the decision to shoot the approach was made because our alternate was about to get hit with thunderstorms and would not be an option to divert to. Our fuel was becoming an issue; and we needed to make sure we had enough to divert elsewhere if our approach in PHL did not end with a landing. Also; I wanted to mention that the windshear escape procedures that we train each year in the simulator worked very well to allow us to fly the aircraft to safety during a windshear encounter low to the ground.
The leading edge of the line was already over the field according to the radar depiction on the map display. The radar display had quite a bit of red; as well as some magenta in the cell over the field. I suggested to the Captain that we ask Approach for delaying vectors until the line had passed the field. He agreed; and the Controller started vectoring us over New Jersey. After around 10 minutes the Captain suggested the storms appeared to be moving past the field and would not be a problem by the time we reached final. I was still concerned; but did not want to be overly obstructive; so I told Approach we could accept the approach.We asked for additional delaying vectors and eventually returned for a visual approach to 9R. We could see that the smoke from local smoke stacks indicated the surface wind was from the west while we were vectoring for the second approach. Notably; when we asked the Controller for the current surface conditions (the ATIS was clearly outdated); he merely read us the current (outdated) ATIS; indicating approximately 20KT tailwind for landing on 9R. We obviously questioned that; and he then clarified that the current surface wind was out of the west at about 6KTS. We felt the second wind report was acceptable considering it would be a visual landing now that the line had moved completely past the field. However; during rapidly changing conditions; the Approach controllers should be aware that any observation older than ten minutes is probably misleading at best.[I believe we should avoid] attempting an approach until a line of thunderstorms is [at least] five miles past the field; and obtain vectors to begin the approach from behind the line of storms.
After delaying their approach while thunderstorms passed over the airport the flight crew of a B757-200 still encountered windshear requiring a go-around during their initial approach. A subsequent approach from the opposite direction was successful.