B-2 Bomber bites the dust...worlds most expensive crash..

[x_man]

First B-2 takes off fine but the second one hits the dirt. Watch closely, both pilots eject a second before impact..

*video doesnt have sound.

********.com - B-2 Bomber Crash Video #2




Whatever the Inquiry board finds later on, but looking at the video, the immediate cause does indeed appear to have been a stall and consequent loss of lift during takeoff. It's still unclear if it was pilot error, i.e., yanking the stick back too far, or some sort of flight control system problem. …. talk about a bad day for that crew... 1.4 Billion $$$$$ down the drain in a few seconds…

 

[Sam Dhanraj]

Whatever the Inquiry board finds later on, but looking at the video, the immediate cause does indeed appear to have been a stall and consequent loss of lift during takeoff. It's still unclear if it was pilot error, i.e., yanking the stick back too far, or some sort of flight control system problem. …. talk about a bad day for that crew... 1.2 Billion $$$$$ down the drain in a few seconds…

Seems that the report is out....

Forgotten Lesson Caused B-2 Crash

Jun 6, 2008
David A. Fulghum/Aerospace Daily & Defense Report

Crews and maintainers never formally recorded information on a vulnerability involving the B-2’s air pressure sensors and the simple workaround crews came up with to mitigate it, a crucial omission that set the stage for a Feb. 23 B-2 crash in Guam.

Aircrews and maintenance teams learned about the sensors’ susceptibility to moisture during a Guam deployment in 2006. They also discovered that turning on the 500-degree pitot heat would quickly evaporate the water and the flight computer would receive normal readings.

But the information was not formally “captured” in maintenance or lessons-learned publications, said Maj. Gen. Floyd Carpenter, president of the accident investigation board and vice commander of 8th Air Force. The result was that by the 2008 deployment, the information was passed on by word of mouth so that “some people knew about it and some people did not,” he said during a Pentagon briefing June 5. Crews never encountered the problem at the bomber’s home base of Whiteman Air Force Base, Mo.

Earlier incident

Earlier in the 2008 deployment, another B-2 had reached 70 knots in its takeoff roll when abnormal indications caused the pilot to abort. The aircraft taxied back to maintenance, the moisture was evaporated with pitot heat and the mission continued without incident.

But on Feb. 23, calibration of the sensors was done without turning the sensor heaters on. The skewed information from three of the 24 air pressure sensors on the Spirit of Kansas fed distorted information into the flight control computer. When the aircraft reached 130 knots, the computer thought it was at the 140-knot takeoff speed and rotated for takeoff.

The sensors also indicated the bomber was in a nose-down attitude so it commanded a rapid pitch up that reached 30-31 degrees before the pilots could correct and stop the climb at an altitude of about 80 feet. The effects of the low takeoff speed and high angle of attack caused the B-2’s speed to deteriorate until the aircraft stalled and began a roll to the left, when its left wing tip struck the ground. At that point the pilots ejected (Aerospace DAILY, March 28).
The aircraft’s remains were boxed and will be sent to the U.S., where the cockpit, seats and hatches will be used for training.

Additional information, including the crash investigators report and video, is posted on Air Combat Command’s Web site at Air Combat Command - Accident Investigation Board Reports.

 

[Sam Dhanraj]

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.

B-2 ACCIDENT REPORT RELEASED