Investigation Summary
The accident originated from a physical blockage in the aircraft's pitot-static system. Clogged pitot tube drain holes allowed moisture or debris to interfere with pressure readings, causing the airspeed indicators to diverge by as much as 45 knots during the descent. The crew attempted to resolve the issue by switching the first officer's instruments to the captain's Air Data Computer (ADC), which extinguished the alerts but did not provide the crew with a verified, accurate airspeed. Crucially, the pilots never cross-referenced their primary displays with the standby airspeed indicator, which would have revealed the error. This lack of verification led the crew to believe the aircraft was flying slower than its actual ground speed. Consequently, they approached the runway significantly above the target landing speed. The MD-11's automated systems also struggled: the flaps failed to extend to the requested 50-degree setting, and the crew opted to land with 35-degree flaps without adjusting for the increased speed requirements. The aircraft touched down late and fast, overrunning the 9,000-foot runway, striking a localizer antenna, and falling off a 30-foot ledge into the bay.
Final Conclusions
The Philippine Aircraft Accident Investigation Board (AAIB) concluded that the primary cause was the flight crew's failure to properly address erroneous airspeed indications and their failure to execute a missed approach when the landing parameters became unstable. Contributing factors included the mechanical failure of the pitot tube drains, an insufficient alerting system for airspeed anomalies on the MD-11, and gaps in the flight manual checklists (such as SEL ELEV FEEL MAN and SEL FLAP LIM OVRD) which did not explicitly direct crews to use the standby airspeed indicator during such discrepancies.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Michael Rooney, age 53.
First Officer
Cynthia Hubbard, age 43.
Systems & Failure Modes
Pitot-Static System
Supplies air pressure data to the Air Data Computers to calculate airspeed; in this case, clogged drain holes caused pressure traps and false readings.
Air Data Computer (ADC)
Processes pitot and static pressure to provide flight data; the crew unified their displays to a single ADC, which masked the underlying error rather than fixing it.
Ground Proximity Warning System (GPWS)
Provided multiple 'sink rate' and 'pull up' alerts during the final approach, which the crew ignored.
Interesting Facts
- 01Both pilots survived the crash with only minor injuries and evacuated through the cockpit windows.
- 02The aircraft, an MD-11F, was a total hull loss and was written off.
- 03The aircraft was named 'Joshua'.
- 04The pitot tube drain holes were found to be clogged, which was the physical trigger for the erroneous airspeed readings.
- 05The crew did not consult the standby airspeed indicator at any point during the emergency.
- 06The captain had 14,000 total flight hours, including 1,430 on the MD-11.
Safety Actions & Advisories
FCOM Revision
Boeing revised the MD-11 Flight Crew Operating Manual on June 15, 2000, to provide better guidance for identifying erratic airspeed through specific alert combinations.
Enhanced Training
FedEx transitioned from annual to semiannual recurrent training for flight crews to improve proficiency in handling complex system failures.
Maintenance Inspections
The final report recommended that all MD-11 and DC-10 operators perform more frequent and detailed inspections of pitot tubes and drain holes.