Air Force officials are pointing to pilot error and possible engine problems as the cause of the first ever combat loss of a CV-22 Osprey, according to a press release summarizing the investigation report released last night.
While the service’s accident investigation board couldn’t determine the cause of the crash “by the standard of ‘clear and convincing evidence,’ in part because the flight incident recorder, the Vibration Structural Life and Engine Diagnostics control unit, and the right engine were destroyed,” it did find that 10 factors likely contributed to the fatal accident.
Those factors that combined to doom the flight, which was the crew’s first combat mission, were:
Inadequate weather planning, a poorly executed low visibility approach, a tailwind, a challenging visual environment, the mishap crew’s task saturation, the mishap copilot’s distraction, the mishap copilot’s negative transfer of a behavior learned in a previous aircraft, the mishap crew’s pressing to accomplish their first combat mission of the deployment, an unanticipated high rate of descent and engine power loss.
Engine power loss. That’s going to give Osprey critics plenty of fodder to throw at the program.
Here’s an excerpt from the accident investigator’s actual report. It further damns the engines:
Close analysis of video indicates that there is an unidentified contrail type emission from the MA during the last 17 seconds of flight. (Tab Z-27, Tab HH-26, Tab II-59) The greater weight of credible evidence indicates that the abnormal and intermittent emission could be heat or fuel mist from an attempted engine auto-relight, or smoke.
I considered engine percent performance, which was last measured on 6 April 2010 (99.5% for the left engine and 95.3% for the right engine). The MA performed four austere landings, including one with a left engine air particle separator failure, after that 6 April 2010 measurement. (Tab D-4, Tab U-5 thru U-6, Tab V-59.3, Tab BB-64, Tab II-3, II-52) Degraded engines could have led to engine failure, surge/stall or insufficient power when a high power demand was required. I determined, by the greater weight of credible evidence, that one or both of the MA’s engines was degraded below acceptable standards.
The report later states say that a likely engine malfunction forced the pilot to execute a “remarkable” rolling landing rather than a helicopter-style landing, which is standard for the V-22. Apparently the tiltrotor hit a two foot ditch after the pilot executed a near perfect “roll on landing” and flipped, killing four, including the pilot, and injuring another 16.
But here’s where it gets a little strange. The press release states that investigators could not conclude with 100 percent confidence that engine power loss “substantially” contributed to the crash.
The convening authority approved the board president’s report, with comments. While legally sufficient, he assessed the evidence in the AIB report did not support a determination of engine power loss as one of the 10 substantially contributing factors. The convening authority made this decision based upon the evidence in the AIB report and additional analysis of the evidence in the report. The convening authority concluded the preponderance of credible evidence did not indicate engine power loss as a substantially contributing factor of the mishap.
The press release goes on to say that Air Force Chief Gen. Norton Schwartz actually requested a second investigation into the crash after the first was completed. That investigation looked at data from the Navy’s air systems command — who runs the V-22 program for the DoD — and video footage of the crash. Still, the only thing the second investigation found different from the first was the estimated airspeed of the tiltrotor at the time of the crash; 80 knots compared to 75.
{ 29 comments… read them below or add one }
The flight incident recorder was destroyed? I expect accidents are going to happen, and that combat conditions increase that risk. But someone *with knowledge* please explain how in the hell an indestructible flight recorder, something we've been putting on aircraft for decades, is not on this machine.
so recorded data and coms dont get into the hands of the enemy
There we go, I was waiting on some smartmouth like yourself. Why have an incident recorder at all? …Because it's only for recording "incidents", and they expect the crew will get home or destroy the sensitive materiel, right? But can you ever guarantee that some enemy tech exploitation people won't get their hands on an incident recorder? So think carefully- is every bit of parametric data and recording "sensitive" from an OPSEC standpoint?
But to be fair I should add that the USAF bombed the wreckage. Crashed civilian aircraft don't receive such treatment. Shame they didn't salvage the recorder, then.
FDR's emit a location signal. If the enemy has the FDR you have the exact enemy location.
This investigation can't find the cause, so it has thrown out plausible explanations. The investigation findings really indicate there is insufficient evidence to place blame. This leads to a pilot error finding every time.
Yeah, it was pilot error, alright. The pilot made the error of flying the piece of crap.
you're an idiot and know nothing about the v22
"Those factors that combined to doom the flight, which was the crew’s first combat mission, were: Inadequate weather planning, a poorly executed low visibility approach, a tailwind, a challenging visual environment, the mishap crew’s task saturation, the mishap copilot’s distraction.."
Oh, they mean all the crap that is bound to happen in a combat zone, when it really counts?
Has a flight incident recorder ever been destroyed by a munition that accidentally went off as a consequence of a crash?
All munitions aboard the aircraft would have been individual basic loads. About 200 rounds per pack of 5.56 mm. plus the SAW rounds of a couple of thousand. And a couple of dozen 40mm gernade rounds. One of the basic complaints about the V-22 is it has no fire power. There have been 7.62mm machine guns placed on the rear ramp but that's about it.
I want to see this video. An engine power failure isn't supposed to cause a crash, certainly not one violent enough to destroy the flight recorder. Am I correctly hearing that this crash was on landing approach?
I'm fairly certain that it did not. My understanding is that the aircraft was lost during a mission. The 'rolling landing' referred to here was an attempt to conduct an emergency landing in the field due to technical malfunction. That is how I understood it at least.
In the artical it says that 4 people where killed, including the pilot, and injuring another
16. It does not sound that violent of a crash to destroy the flight recorder.
yes, the CV-22 has a 38ft wing span, when the tiltrotors are in airplane mode the blades overlap the bottom of the fuesalage by like 6 feet. so when they hit the ground they obviously destroy. they are a different material so when they hit they shatter without hopefully destroying critical partsof the aircrsft. obviously it can only do this ONCE. a need to land like this may happen if the tiltrotors get jammed or a malfunction to rotate happens. or mabey a air problem. they wer landing good, (for landing this way, only in a emergency) but like i said the blades over lap, so as its coming in if there is a edge to the runway, a dropdown and 6 feet of the blad comes along the side from under the fuesalage it can catch and force it in the oppisite direction on the aircraft.
However, Lt. Gen. Kurt Cichowski, vice commander of Air Force Special Operations Command, the convening authority for the investigation board, ruled that engine power loss could not be considered as a major factor in the accident.
http://www.aviationweek.com/aw/blogs/defense/inde…
It seems like the investigation went out of its way to avoid blaming the aircraft, but it's clear with out the engine failure the pilot would have had more options than to "press ahead" with the landings. More thoughts and the full accident reports at http://www.lineofdeparture.com/2010/12/17/v-22-os…
The FIR was not lost until the DoD ordered the destruction of the scene via friendly munitions after the CASEVAC was complete. It was not lost in the crash or due to some secondary explosion from the crash.
The obvious explanation looking at the data presented is this:
The engine failure alone would not have cause the crash due to the redundant transmission, and the co-pilot's reflexive "transfer of behavior" from the wrong aircraft would not have caused the crash.
And even those two failures combined weren't enough to cause a crash, because the pilot landed successfully.
It wasn't until they taxied into a ditch that the aircraft flipped over.
I'm still not sure quite how the DoD can get away with blowing up such an expensive piece of equipment, just because they cant come salvage it right away.
It's not like the insurgent's are going to steal the whole thing, and the technology is nothing particularly new.
If they have some sensitive equipment that they can't afford let anyone see, they should just make the part removable so the crew can drag it away from the airframe so it can be blown up selectively.
So they evacuated the 16 seriously wounded and pulled four dead out the wreckage, but no one at the crash site thought it important to grab the flight incident recorder.
Note that a USAF Colonel was quoted in AvWeek last Feb that a CV-22 could not safely hover above 4000 feet. So this aircraft was attempting to land at 5000 feet full of passengers, flown by the USAF's most experienced CV-22 pilot, an "evaluator" pilot. He had flown dozens of combat missions, but that was the first for that crew.
Note that lack of engine power does not mean loss of engine power. He began the approach, he began to exceed the max descent rate of 800 fpm, something the flight engineer calls aloud. Unable to arrest his sink rate due to a lack of engine power for the small tiltrotors with limited HOGE, he followed SOP and tilted the engines forward to gain forward airspeed and lift, but lacked the clearance to perform a go around so the props hit the ground and it crashed.
General Harvel is right, the pilot didn't go insane and decide to perform a rolling landing in rough terrain at night, especially with the CV-22s known weak nose wheel. If he were trying to land, the proprotors would not hit.
So after this report, General Harvel, a graduate of the USAF saftey/mishap school and the safety/mishap board President's school was retired/fired. A three-star General who didn't conduct the investigation overruled him. Note this was the second investigation of that crash, the Bell-Boeing reps wearing blue suits rejected the first investigation outright, and ordered a second, which they didn't like either.
Lucky for them, everyone "forgot" to recover the flight incident recorder. Finally, the reason for investigations made public is so that everyone knows the cause so future incidents can be avoided.
Stan,
You are the only one who nailed it. You analysis is spot on. I would like to add a couple of comments to your posting.
In addition to Brig. General Harvel’s qualifications that you mention, he was a CV-22 pilot. (and I would also put more emphasis on the ‘fired’ description of his departure from the military.)
Lt. General Kurt Cichowski was a fighter pilot and… oh, by the way… he was promoted and he is now with the CIA as the Associate Director for Military Affairs.
Also, all of the individuals on the investigation board who agreed with General Harvel’s opinion have all been put on the chopping block. Their military careers are also over.
With those twin tails, does the V-22 have any adverse directional control or coupling issues at low speedranges in a tailwind? And doesn't the CV-22 carry more fuel?
I think that the link between the low transit speed (20-30 knots shy of allowable for a mission TOT which was _late_) and the fact that there were TWO vapor streams, TWICE, on an airframe which was commanded slow .5nm late is indicative and linked causation/behavior.
The MP knew he had a heavy bird and knew he was operating in a regime where he had limited hover authority off the cushion.
So he brought the aircraft up hard and kept the speed high to crab what were likely mushy power controls (110 knots should be firmly in the rotorcraft mode but weight will be a limiting factor for differential blade pitch to avoid VRS) and then realized he couldn't get it down and IGE without excess vertical and/or forward speed.
So he dumps fuel as late as he can and realizes that isn't gonna do it either, tries for the go around and doesn't get the power-on transition because the proprotors are too high and are commanding pitch rather than RPM.
V-22 stability in the hover mode is explained here http://www.g2mil.com/V-22survive.htm
Here is the key part, that link has a link to the NASA study:
A third problem is the V-22's boxy fuselage, which provides more internal volume than older cylindrical shapes, although 25% less than the CH-46E. However, this allows high winds to push it sideways, a situation made worse by the large side profile of the engines and tail. This makes hover operations in high winds dangerous as the V-22 wants to "weathervane" and turn. A V-22 requires up to 80% more power to hover in high winds, and if extra power is not available because it is loaded with payload, control may be lost. A 2005 NASA study (pdf) provides details on this problem.
Altitude is another power limiting factor; critical in current Afghan ops.
The remaining points of interest to me are terrain slope index on the designated landing ground and how (long) the second designator beam (A-10) may have messed up approach orientation to begin with.
As much as I am a fan of the V-22, I think that everyone who knows the airframe, knows it's _not_ a fast helicopter intended for hostile insertions but rather a VTOL fixed wing airplane designed to bring forces to the field, not the fight.
If you can't use it's extra range and speed to find level ground (a road, a plowed field…) then you are not doing yourself any favors trying to relive Vietnam's airmobile operations. You know, the ones where we lost 4,500 Hueys…
If the wings are spinning, you're in trouble.
Thanksgiving Day Massacre – Turkey kills two more marines.
It's SOP to bomb the crash site of any V22 to make sure that hostile forces (such as crash scene investigators) can't make off with sensitive information.
March 28, 2010, Aviation Week
http://www.aviationweek.com/aw/generic/story_gene…
An Army Spec Ops Colonel disses the CV-22 flown by his USAF co-workers in the press, saying the Army don't want them. Col. Clay Hutmacher, of the 160th said:
Above 4,000 ft., there's a significant [hovering] limitation on the V-22, he said. Tiltrotor engineers concede that while the V-22 hovers well in many situations, the special twist and size of its proprotors leave it unable to carry as much useful load pound-for-pound as most helicopters hovering in similar conditions.
I'm not disparaging the V-22, Hutmacher said. Hovering ability, however, is critical to the 160th, because at the end of the day, our mission is going to terminate in a hover.
____________________
Certainly, everyone in the small CV-22 community read that. One week later, "someone" decided to send three fully loaded CV-22s to hover land at 5226 feet in their first Afghan combat mission. The first to land crashed because it couldn't terminate in a hover. Wow!
The V 22 Osprey Program. Was'nt this program discarded by the Brits back in the late '70s due to the high casualty rate ( test pilots and aircraft) combined? Now we have rummaged through the rubbish can, found the programme, presented it as our own and now faced with the same issues as our cousins across the pond, we have now pulled the wool over our heads while seeking an enlisted scapegoat for this latest tragedy. Let's face it, Britain scrapped the V 22 program because the aircraft could'nt differentiate between rotor and prop.
Maybe redesign? Get rid of the wings, mount engines on side, gear box for large counter rotating rotors. Should be able to get close enough airspeed as mention.