B-2 Accident Investigation

[tigershark]

B-2 Accident Investigation
The first-ever B-2 crash occurred Feb. 23 at Anderson AFB, Guam. B-2 bombers have been flying almost 20 years and are renowned in the Air Force for their unprecedented safety record. The 20 bombers combined have logged more than 14,000 sorties, 100 combat sorties and 75,000 flying hours without a single Class A mishap before this accident. A mishap is categorized as Class A when there is loss of life or damage in excess of $1 million. The B-2 that crashed was named Spirit of Kansas. It had logged more than 5,000 flight hours and 1,036 sorties before Feb. 23.

B-2 ACCIDENT REPORT RELEASED
Release Number: 020608

6/5/2008 - LANGLEY AIR FORCE BASE, Va. -- Distorted data introduced by a B-2 Spirit's air data system skewed information entering the bomber's flight control computers ultimately causing the crash of the aircraft on takeoff at Andersen Air Force Base, Guam, Feb. 23, according to an Air Combat Command accident investigation report released today.

Moisture in the aircraft's Port Transducer Units during air data calibration distorted the information in the bomber's air data system, causing the flight control computers to calculate an inaccurate airspeed and a negative angle of attack upon takeoff. According to the report, this caused an, "uncommanded 30 degree nose-high pitch-up on takeoff, causing the aircraft to stall and its subsequent crash."

Moisture in the PTUs, inaccurate airspeed, a negative AOA calculation and low altitude/low airspeed are substantially contributing factors in this mishap. Another substantially contributing factor was the ineffective communication of critical information regarding a suggested technique of turning on pitot heat in order to remove moisture from the PTUs prior to performing an air data calibration.

The pilot received minor injuries, and the co-pilot received a spinal compression fracture during ejection. He was treated at Tripler Army Medical Center, Hawaii, and released. The aircraft was assigned to the 509th Bomb Wing at Whiteman Air Force Base, Mo.

The cost of the lost aircraft is about $1.4 billion.

For more information, contact the Air Combat Command Public Affairs office at (757) 764-5007 or email accpa.operations@langley.af.mil.

Source
http://www.acc.af.mil/media/archives/story.asp?id=123101589

[SAS73]

here is the video:

http://www.patricksaviation.com/in/4395?i=9K9

[AviaL2]

http://uk.youtube.com/watch?v=_ZCp5h1gK2Q

[Globetrotter]

It's a pity such a costly aircraft was lost, and human lifes endanagered, by such a thing...

This is one of the reason I believe aircraft should never be commanded only by computers

[iluveagles]

True, however it is an amazing aircraft when it works...............and it was human failure partially............

[tigershark]

The aircraft functions very well with over 14,000 flights and has a great overall record.   One day if might a the first stealth tanker too and  filling up Block-II F/A-22 on deep strikes into enemy territory.   

[MightyHunter]

Well as an aircraft engineer i know a thing about pitot heaters like a lot of people but to not have pitot heaters on pre take off checklist is a small error that has cost a lot of money.
On the Nimrod I work with pitot heaters come as 2 switches you turn on or part of checks before putting power on the aircraft you ensure are off as they get extremely hot and will melt skin when touched.
So moisture in them caused the computer to bugger up , maybe its time to have a backup or more than 3 pitots all to have moisture is quite bizzare. Good ejection though and lucky nobody was hurt bad thats all that matters , for the US taxpayer ouch