M2 Posted June 6, 2008 Share Posted June 6, 2008 From AFA today (after you read through all the articles about Buzz and Wynne resigning...) B-2 Felled By Sensor Problem: As we reported in May, faulty readings in air data sensors caused the Feb. 23 crash of a B-2 bomber taking off from Guam, the service's accident investigation board president said June 5. Announcing the AIB's findings to reporters via teleconference, Maj. Gen. Floyd Carpenter, vice commander of 8th Air Force, said moisture got into three of the B-2's 24 air data sensors, also called pitots, which detect air pressure and derive information such as altitude. The moisture threw off the accuracy of the sensors, which then disagreed with readings taken by the other 21, and the aircraft's computers recommended a recalibration. A procedure that would have evaporated the moisture and made the recalibration more accurate--switching on heaters in the system--wasn't used, Carpenter said. However, the procedure wasn't official; it was passed from one technician to another verbally, and the airman performing the recalibration that day wasn't aware of it. Carpenter said that, when the aircraft began its takeoff roll, the faulty data fooled the bomber into thinking it was actually pitching down and going faster than its actual speed of 130 knots. To recover, it made an uncommanded pitch up of about 31 degrees, and got about 80 feet off the ground before stalling and rolling left. When the left wingtip touched the ground, the two pilots ejected, safely. Carpenter said the two pilots "acted as they should have" and dealt with the situation and some momentary cockpit warnings as they were trained to do. He also said the technician who did the calibration probably wasn't to blame because he wasn't required to know of the pitot heat procedure. The air data sensor problem had manifested just once before, in 2006, and also at Guam. But because it was so rare, the pitot heat procedure wasn't added to the technical manual. It has now been added, along with a number of additional inspections. Carpenter said the AIB saw no inherent flaw in the B-2's design or flight controls. --John A. Tirpak Link to comment Share on other sites More sharing options...
JarheadBoom Posted June 6, 2008 Share Posted June 6, 2008 Wow... Not sure what was worse to see, the security camera video or the ground video (from the link that Fuse provided). Does anyone else think the security camera video showed a lack of prompt response from the crash crew? Or did the initial responding vehicles go to the pilots first (which was obviously way out-of-frame)? Link to comment Share on other sites More sharing options...
JarheadBoom Posted June 6, 2008 Share Posted June 6, 2008 Of 24 pitots and static ports, 3 being inaccurate causes a 31 degree pitch up? When has moisture ever given you a pitch down and fast airspeed indication? I call B/S. Obviously, it was a failure of it's leading edge electrogravitic system. :) The Executive Summary on the ACC webpage says that the moisture ingress caused the air data recalibration (a maintenance procedure they seem to have done AFTER the moisture was flagged by the aircraft's computers, before the "flight") to be WAY off, causing the early rotation & pitch-up. There apparently wasn't moisture in the system at the time of the mishap. $1,407,006,920. Link to comment Share on other sites More sharing options...
MD Posted June 6, 2008 Share Posted June 6, 2008 (edited) Does anyone else think the security camera video showed a lack of prompt response from the crash crew? Or did the initial responding vehicles go to the pilots first (which was obviously way out-of-frame)? As that was my old gig, and still part time, I'll toss in 2 cents. The standard is to be able to get from the crash station to the furthest runway in 3 mins, which is why some airfields have multiple stations on the field apart from the main one. The AF no longer performs "hot spot" duty as a standard (a few bases do)....that is where you have a truck posted up "on deck" near the runway during flight ops; the USN/USMC still does regularly; so it's going to take them a reasonable time get the call, gear up, and roll out of the station (unless of course they already had guys watching the takeoff out of interest, etc.). If the crash crew sees the crew bailout, and they're reasonably certain that that's everybody, then the first arriving trucks will head to the victims first.....the burning wreckage is now simply burning junk. Had this been a, for example, C-141 or KC-10/135, they'd be all over the main wreckage foaming an escape path for any surviving crew/pax. Edited June 6, 2008 by MD Link to comment Share on other sites More sharing options...
JarheadBoom Posted June 7, 2008 Share Posted June 7, 2008 As that was my old gig, and still part time, I'll toss in 2 cents. The standard is to be able to get from the crash station to the furthest runway in 3 mins, which is why some airfields have multiple stations on the field apart from the main one. The AF no longer performs "hot spot" duty as a standard (a few bases do)....that is where you have a truck posted up "on deck" near the runway during flight ops; the USN/USMC still does regularly; so it's going to take them a reasonable time get the call, gear up, and roll out of the station (unless of course they already had guys watching the takeoff out of interest, etc.). If the crash crew sees the crew bailout, and they're reasonably certain that that's everybody, then the first arriving trucks will head to the victims first.....the burning wreckage is now simply burning junk. Had this been a, for example, C-141 or KC-10/135, they'd be all over the main wreckage foaming an escape path for any surviving crew/pax. Makes sense that they would go to an ejected crew first, and let the wreckage burn - that's what I had hoped to hear, and what I hope happened for the B-2 crew. I hadn't really noticed the lack of a hot spot truck until you posted it... and now that you've got me thinking about it, I don't ever recall seeing one on an AF base. Interesting... Link to comment Share on other sites More sharing options...
MD Posted June 7, 2008 Share Posted June 7, 2008 Makes sense that they would go to an ejected crew first, and let the wreckage burn - that's what I had hoped to hear, and what I hope happened for the B-2 crew. I hadn't really noticed the lack of a hot spot truck until you posted it... and now that you've got me thinking about it, I don't ever recall seeing one on an AF base. Interesting... Yeah, check it out next time you go into an NAS/MCAS...usually near midfield, you'll see a crash truck parked under a canopy with some of the crew asleep and others reading/sunbathing, etc. As part of the duties for the day, trucks and crews rotate every so many hours. Only a few AFBs still have hot spot....Tucson ANGB in AZ comes to mind as one. Of course, any fighter base performing hot-pit refueling will have a truck standing by the pits when these ops are going on. Of course, there are positives and negatives to hotspot duty. The bad is that aircraft on takeoff or landing could crash into you. The good is that you're right there, in fact there have been a number of incidents where the crash crew at the hotspot have witnessed an accident in the making or just happening, and are able to be on scene almost as the wreckage is coming to a halt. Link to comment Share on other sites More sharing options...
TacAirCoug Posted June 9, 2008 Share Posted June 9, 2008 Wow, I'm actually going to beat M2 to the punch! From the AFA: More on the B-2 Crash: While the lessons learned from the crash of a B-2 bomber in February aren't applicable to the Air Force's other stealth platforms, the F-22 and F-35 fighters, there are "other systems being deployed" that will benefit from the insights, Maj. Gen. Floyd Carpenter, vice commander of 8th Air Force, who led the B-2 accident investigation board, told reporters June 5. However, Carpenter declined to elaborate on what the other platforms might be, although a best guess would be next-generation long-range strike prototypes. Whatever the case, the AIB found that distorted data introduced into the B-2's flight control computers during takeoff from Anderson AFB, Guam on Feb. 23 caused "an uncommanded, 30 degrees nose-high pitch-up" resulting in a stall and subsequent crash. Both pilots ejected. Moisture in port transducer units--which are essentially air data sensors also called pitots--during air data calibration led to faulty readings for which the flight control computers then tried to correct, leading to the pitch and stall. Carpenter said the aircraft lost, named Spirit of Kansas, was one of the best-performing and least problem-prone of the B-2 fleet, now down to just 20 aircraft. It had accumulated about 5,200 hours of flying time. Carpenter said the AIB doesn't assign culpability and any disciplinary measures will be up to unit commanders to determine. (Click here for Air Combat Command's Web page on the accident investigation, which includes the AIB documentation and videos of the actual mishap.) There are two videos of the crash on the ACC page linked above...WOW! Link to comment Share on other sites More sharing options...
Guest Johann Posted June 9, 2008 Share Posted June 9, 2008 There are two videos of the crash on the ACC page linked above...WOW! That second (ground) video would've been great, if the camera-man hadn't been such a f*ck-up. Link to comment Share on other sites More sharing options...
JarheadBoom Posted June 10, 2008 Share Posted June 10, 2008 Yeah, check it out next time you go into an NAS/MCAS...usually near midfield, you'll see a crash truck parked under a canopy with some of the crew asleep and others reading/sunbathing, etc. As part of the duties for the day, trucks and crews rotate every so many hours. Only a few AFBs still have hot spot....Tucson ANGB in AZ comes to mind as one. Of course, any fighter base performing hot-pit refueling will have a truck standing by the pits when these ops are going on. Of course, there are positives and negatives to hotspot duty. The bad is that aircraft on takeoff or landing could crash into you. The good is that you're right there, in fact there have been a number of incidents where the crash crew at the hotspot have witnessed an accident in the making or just happening, and are able to be on scene almost as the wreckage is coming to a halt. I spent 11 years in Marine Air, so I'm pretty familiar with USN/USMC crashcrew ops. And the only canopy I ever saw over the hotspot was at Yuma - it was just a concrete pad at all the other air stations I've been to. Maybe that's a new thing - I haven't been to an MCAS since '03. Side note - NAS Willow Grove didn't have a "hot spot", but they always had a truck slowly roaming the flightline and taxiways. Kinda annoying a few times when we were taxiing out of our line and had to wait on the truck to clear the parallel taxiway so we could go... Link to comment Share on other sites More sharing options...
drewpey Posted July 16, 2008 Share Posted July 16, 2008 http://www.popularmechanics.com/science/ai...ce/4273248.html Some pictures of the wreckage...for as big as the fireball was, looks like it held up pretty well considering! Also has a small timeline of the mishap. Link to comment Share on other sites More sharing options...
Nineline Posted July 16, 2008 Share Posted July 16, 2008 http://www.popularmechanics.com/science/ai...ce/4273248.html Some pictures of the wreckage...for as big as the fireball was, looks like it held up pretty well considering! Also has a small timeline of the mishap. While the article is well written and the pics interesting to look at, the real gold mine are the comments at the bottom -- especially the few posted by the village idiots, such as: 25. "I have heard that a B-2 stealth bomber costs nearly a billion USD. Such a small error had caused a billion dollar loss.People should try to be more careful." Great insight, Sherlock! With your advanced deductive reasoning, maybe we should suggest all pilots be more careful when performing their duties. That'll fix everything! -9- Link to comment Share on other sites More sharing options...
Butters Posted July 16, 2008 Share Posted July 16, 2008 maybe we should suggest all pilots be more careful when performing their duties. That'll fix everything! I always love it when ground clears me to taxi and says "use caution"... if they didn't always tell me that I would probably just taxi with reckless abandon. Link to comment Share on other sites More sharing options...
FallingOsh Posted July 16, 2008 Share Posted July 16, 2008 I like this comment. I guess its all a conspiracy. 27. RE: B-2 Stealth Bomber Crash Scene Photos: Exclusive First Look I remember reading somewhere several years ago that the B2 had a near-fatal flaw that the Air Force was covering up: the planes wouldn't function correctly if they were allowed to get wet. They had to be kept in hangars at all times, and couldn't be flown in bad weather. It appears that the story was true, and somebody screwed up by allowing this one to get wet. That's right, they spend a billion dollars apiece on planes that won't work if they get wet. And they keep it a secret from us. Link to comment Share on other sites More sharing options...
Guest HercengTN Posted July 16, 2008 Share Posted July 16, 2008 Please excuse my ignorance, but I am not familiar with the "Auto Override". Im not sure I would like having the system on my ACFT. Is there a way to manually override it in cases like this ( I realize in this incident the crew didn't have the altitude nor time ). How many other ACFT have this system? 9:29 am /// Waterlogged /// During a preflight check, the pilot notices three air data sensors are malfunctioning. Unknown to the crew, water in the sensors is skewing the air-pressure readings too high. 9:34 am /// Recalibration /// A ground crewman, using a cockpit keyboard, recalibrates the three waterlogged sensors. The preflight checks continue, and the B-2 taxis to runway Zero-Six-Right (above, top left). 10:29 am /// Boiling Sensors /// Before takeoff, the pilot turns on the sensors’ heaters. Water in the sensors evaporates; the readings are now normal, but the earlier fix skews air-pressure data too low. 10:30:12 am /// Slow Start /// The B-2 starts takeoff. The on-board flight computer displays the wrong airspeed, causing the pilot to lift off at 133 knots (153 mph) rather than the required 145 knots. 10:30:50 am /// Auto Override /// The flight computer, relying on bad air-pressure readings, concludes the aircraft is in a nose-low altitude and automatically raises the nose to 30 degrees (top right). 10:31:06 am /// Fiery Ending /// The B-2, going too slowly, with its nose angled too high, stalls. As the airplane’s wing scrapes the runway (bottom left), the pilot and commander safely eject. The B-2 crashes (bottom right). Link to comment Share on other sites More sharing options...
JarheadBoom Posted July 21, 2008 Share Posted July 21, 2008 Please excuse my ignorance, but I am not familiar with the "Auto Override". Im not sure I would like having the system on my ACFT. Is there a way to manually override it in cases like this ( I realize in this incident the crew didn't have the altitude nor time ). How many other ACFT have this system? It's not a push-button or a switch in the cockpit, it's a part of the control laws in the flight control computers. Just like any other computer, to get good output, you have to gave good input. (The old-time computer geeks used to have their own little word for it - GIGO. Garbage In, Garbage Out.) If the computer thinks the aircraft is waaaay nose-low after rotation not because it actually is, but because of a false sensor reading, it's gonna try to bring the nose up to keep the airplane airborne... and it'll keep trying until: A> the computer decides the aircraft is level (regardless of actual aircraft attitude) OR B> the aircraft stalls close to the ground and bellyflops. It could have gone the other way, too - the computers could have thought the B-2 was nose-high, and kept forcing the nose down through the takeoff roll. The pilots wouldn't have been able to "pull through" the computer's flight control inputs at Vr, and it would've over-ran the runway and become the newest aircraft in the underwater collection off Andersen's runway. The pilot-centric solution - wire a guarded switch into the throttles/stick grips that overrides the FCC's air-data inputs that determine aircraft attitude, and allows the pilot to fly the aircraft based on his view out the windscreen. The maintenance-centric solution - rewrite the TO's to include PITOT HEAT/AIR DATA SENSOR HEAT..........ON as a part of the MX daily/preflight inspection. Link to comment Share on other sites More sharing options...
M2 Posted August 6, 2008 Share Posted August 6, 2008 More post-crash info... Cheers! M2 B-2 Stealth Bomber Crash Scene Photos Photographs courtesy of United States Air Force After taking you inside the Air Force's investigation into the crash of a B-2 stealth bomber, PopularMechanics.com has obtained the first still photos of the February accident—and they're pretty stunning. With last month's technical report detailing the demise of the Spirit of Kansas came footage from security cameras at Andersen Air Force base in Guam . Officials also snapped—but, until now, did not release—still photos of that crash site. In the pictures, firefighters work in silvery suits and crash teams cautiously approach the empty ejection seats, which use explosive charges to gain distance from a foundering airplane. Both pilots were able to eject safely through panels in the airplane's cockpit roof. The white spray seen in the photos is fire suppression foam. (Illustrations by Remie Geoffroi) 9:29 am /// Waterlogged /// During a preflight check, the pilot notices three air data sensors are malfunctioning. Unknown to the crew, water in the sensors is skewing the air-pressure readings too high. 9:34 am /// Recalibration /// A ground crewman, using a cockpit keyboard, recalibrates the three waterlogged sensors. The preflight checks continue, and the B-2 taxis to runway Zero-Six-Right (above, top left). 10:29 am /// Boiling Sensors /// Before takeoff, the pilot turns on the sensors' heaters. Water in the sensors evaporates; the readings are now normal, but the earlier fix skews air-pressure data too low. 10:30:12 am /// Slow Start /// The B-2 starts takeoff. The on-board flight computer displays the wrong airspeed, causing the pilot to lift off at 133 knots (153 mph) rather than the required 145 knots. 10:30:50 am /// Auto Override /// The flight computer, relying on bad air-pressure readings, concludes the aircraft is in a nose-low altitude and automatically raises the nose to 30 degrees (top right). 10:31:06 am /// Fiery Ending /// The B-2, going too slowly, with its nose angled too high, stalls. As the airplane's wing scrapes the runway (bottom left), the pilot and commander safely eject. The B-2 crashes (bottom right). Link to comment Share on other sites More sharing options...
Guest Mach2 Posted August 28, 2008 Share Posted August 28, 2008 Just in case you didn't see on the ACC site. Link to comment Share on other sites More sharing options...
JarheadBoom Posted August 29, 2008 Share Posted August 29, 2008 I'm still amazed at how much of the airframe was still intact after the impact/fire... Link to comment Share on other sites More sharing options...
Butters Posted August 29, 2008 Share Posted August 29, 2008 I'm still amazed at how much of the airframe was still intact after the impact/fire... They used really good glue when they built it. Link to comment Share on other sites More sharing options...
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