Date: 201408
Local time of day: 1201-1800
Location: OMDB.Airport, FO
Flight conditions: VMC
Light: Daylight
Aircraft: Widebody Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class C OMDB
ATC / advisory: Tower OMDB
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Situational Awareness; Time Pressure; Distraction; Communication Breakdown; Training / Qualification
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Automation Overrode Flight Crew; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Contributing factors: Procedure; Human Factors; Aircraft
Primary problem: Human Factors

Narrative: Arrival into Dubai was DARAX 3A and was uneventful until TALVI. Approach had brought another airplane over TALVI 2;000 FT below us and was about 1/2-1 mile in front of us. He cleared us to descend from 6;000 to 4;000. We told Approach that we had traffic at 12 o'clock and he said we were going to follow him. As we started descent; the previous plane turned base leg and we continued toward ALNET. He then gave us a 210 heading; followed shortly by a 140 heading and descent from 4;000-2;000. I selected FLCH and speed brakes to get us on down to 2;000 since approach was getting rushed. He then cleared us the RNAV 12L Approach. He also told us to slow to final approach speed. The 140 heading was going to put us just outside of DB601 FAF. After cleared; and established on final; and protected in FMS; I selected LNAV and selected 570 (561) in MCP ALT window. I then mistakenly pushed APP. I was still slowing with boards and descending. If I'd selected VNAV we would've been truly protected to 2;000 till DB601. By selecting APP; I had taken out the 2;000 protection. With letting myself get rushed and trying to slow I descended several hundred feet below the planned path of 2;000 FT. My First Officer said we were low and I disconnected the autopilot and climbed to 2;000 just by DB601. I reconnected the autopilot and continued approach to landing. ATC seemed to be trying to rush us and I let them; which led to me making errors. I also just finished HUD training; and I think that added a little extra distraction. Not trying to put blame on ATC or HUD; just pointing out possible factors that could've contributed. I could've not let ATC put us so close to other plane which caused us to slow down while trying to get down. Should've just had them extend our downwind leg. Obvious selecting APP instead of VNAV is primary reason of breakdown. Turning OFF HUD/EFIS would've eliminated an unnecessary distraction.


Second narrative: I was completing the before landing checklist and when I looked at my PFD; I realized that we had descended below 2;000 FT and we were at 1;200 FT prior to DB601. I called out 'altitude' and the Captain immediately realized he was too low and disengaged the AP and hand flew back up to 2;000 FT. As soon as we reached 2;000 FT we were crossing DB601; which was the FAF; and we started our descent to the DA already fully configured and on speed. Approach Control never queried our altitude and handed us off to contact the Tower.I suggest: 1. Always verifying your FMA's before changing altitudes.2. Practice more RNAV approaches. 3. Do a more thorough brief of the approach to familiarize yourself with the RNAV procedures.


Synopsis: A widebody crew on the OMDB RNAV Runway 12L became rushed attempting to slow and descend behind traffic. The Captain selected APP while descending to the 2;000 FT FAF crossing constraint and the busy First Officer detected the aircraft descending at 1;200 FT prior to the FAF and alerted the Captain who climbed to 2;000 FT.