Update: B-2 Crash Caused By Waterlogged Sensors

Editorial Staff

Thursday, June 05, 2008 at 12:00 AM ET

Verified

Key Takeaways:

The crash of a B-2 Spirit bomber on takeoff was primarily caused by moisture in its air data sensors, which led to distorted airspeed and angle of attack readings, resulting in an uncommanded nose-high pitch-up.
The $1.4 billion aircraft, in its first-ever crash, was destroyed, while its two pilots safely ejected but sustained injuries, including spinal compression fractures for one.
Ineffective communication regarding a technique to remove moisture from sensors (activating pitot heat), which was not incorporated into official checklist procedures, contributed to the accident.

See a mistake? Contact us.

The crash on takeoff of a 509th Air Wing, Air Force B-2 Spirit bomber, Feb. 23, operating at Andersen Air Force Base, Guam, was caused by water in the aircraft’s sensors, according to an Air Combat report issued Thursday. Specifically, moisture in three port transducer units “distorted data introduced by a B-2 Spirit’s air data system” that led to flawed information entering the bomber’s flight control computers. The aircraft was reacting to inaccurate airspeed and a “perceived” negative angle of attack. This resulted in an “uncommanded 30 degree nose-high pitch-up on takeoff,” according to the Air Force.

Major Ryan Link and Captain Justin Grieve, the aircraft’s two pilots and the only two aboard, were unable to regain control and safely ejected just as the aircraft stalled and mushed into the ground and its left wing impacted the ground. The $1.4 billion aircraft crashed just off the left side of the runway and exploded. It was the first-ever B-2 crash and followed 75,000 hours of loss-free service. Link and Grieve both suffered injuries during ejection, with Grieve suffering compression fractures to his spine.

The report points to the inaccurate readings as contributing factors, adding that ineffective communication of critical information about a technique used to remove moisture from the sensors also contributed. It’s possible that all the maintenance crew had to do to avert the accident was turn on the pitot heat prior to performing air data calibrations. But the suggested technique was not part of checklist procedures.