Widebody Transport
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Confusion; Communication Breakdown; Workload
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Weather
After 5-10 minutes of vectoring and numerous descents we were finally given a 45 degree vector to intercept the final approach course while descending to an altitude assigned of 3;500 FT. We were between 22-24 NM from the runway for the ILS to Runway 27. The Approach Controller cleared us to intercept the localizer and descend to 2;900 FT. (The Controller later told us that we were cleared to intercept the localizer and at 15 DME to descend to 2;900 FT). Both of us (the Captain and I) heard the; descend to 2;900 part but not the 'at 15 DME' part that the Controller says was included. This unusual approach clearance was not picked up by either of us. As we approached 2;900 FT and neared the localizer we heard 'TOO LOW TERRAIN' with an amber terrain indication on the PFD. We executed a missed approach and then returned immediately to complete an uneventful approach and landing.We misunderstood the ATC clearance. The clearance was not a clearance that is usual for the final approach segment with terrain in the vicinity in IMC conditions. Language issues were definitely a problem. The Controller was very busy and may have been trying to save time by clearing us to descend to 3;500 FT and at 15 DME to descend to 2;900 FT. ATC should not issue conditional descent clearances on final approach in IMC.
I reported this to the Controller and she said that our clearance was to descend at 15 DME to 2;900 FT. I requested radar vectors for another approach and returned for a normal landing. This was a non-standard clearance that we're not accustomed to hearing in the terminal area; especially on final. Normally when lower altitude instructions are given the pilot is expected to begin descent; or if on final to maintain the assigned altitude until glidepath intercept on an ILS. Because of the weather conditions; radio congestion; and language differences; I misinterpreted a very important clearance. I was familiar with the airport and the local terrain; but got distracted by a combination of other factors. ATC using standard descent clearances. When it's safe to descend they tell you to descend.
While on a VABB Runway 27 ILS in heavy rain; a rushed TRACON Controller issued a descent clearance from 3;500 FT to 2;900 FT but the crew did not hear at 15 DME; so while descending the EGPWS alerted TOO LOW TERRAIN prompting the escape maneuver.