USMC MV-22B Accident - South of Bodo
Thanks for linking the investigation. From page 19 and 20:
.....After conducting the descent, GT31 began maneuvering at greater than 45 degrees angle of bank (AOB) while transiting around terrain along the Grátádalen valley at speeds of up to 259 knots calibrated airspeed (KCAS) , 39 knots faster than VMM-261’s default LAT planning airspeed. GT31 conducted a left-hand turn to follow the river valley. During this turn, the aircraft reached 68 degrees AOB. The NATOPS limit for AOB in an MV-22B is 60 degrees. An MV-22B is unable to maintain both altitude and airspeed at 68 degrees AOB in any published airplane configuration flight regime published in Energy-Maneuverability Diagrams. GT31 lost altitude and airspeed following the left-hand turn and began rapidly closing the distance to the western wall of the valley. In an effort to avoid the terrain, OT31 conducted a right-hand turn that reached 89 degrees AOB. At the time of this right-hand turn, GT31’s airspeed was 202 KCAS and its altitude was 1261 feet above mean sea level. GT31 came as close as 27 feet from the western valley wall during the maneuver. Attempting to complete the turn at 89 degrees AOB placed the aircraft well outside of the tested aircraft maneuverability capabilities. The highest AOB depicted on any MV-22E airplane configuration Energy Maneuverability Diagram is 75 degrees. Flight in this regime is unsustainable and results in the aircraft rapidly descending........
.....After conducting the descent, GT31 began maneuvering at greater than 45 degrees angle of bank (AOB) while transiting around terrain along the Grátádalen valley at speeds of up to 259 knots calibrated airspeed (KCAS) , 39 knots faster than VMM-261’s default LAT planning airspeed. GT31 conducted a left-hand turn to follow the river valley. During this turn, the aircraft reached 68 degrees AOB. The NATOPS limit for AOB in an MV-22B is 60 degrees. An MV-22B is unable to maintain both altitude and airspeed at 68 degrees AOB in any published airplane configuration flight regime published in Energy-Maneuverability Diagrams. GT31 lost altitude and airspeed following the left-hand turn and began rapidly closing the distance to the western wall of the valley. In an effort to avoid the terrain, OT31 conducted a right-hand turn that reached 89 degrees AOB. At the time of this right-hand turn, GT31’s airspeed was 202 KCAS and its altitude was 1261 feet above mean sea level. GT31 came as close as 27 feet from the western valley wall during the maneuver. Attempting to complete the turn at 89 degrees AOB placed the aircraft well outside of the tested aircraft maneuverability capabilities. The highest AOB depicted on any MV-22E airplane configuration Energy Maneuverability Diagram is 75 degrees. Flight in this regime is unsustainable and results in the aircraft rapidly descending........
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Pretty SAD headline - no pooofraders at USNInews: Marine Corps Investigation Into MV-22B Osprey Crash in Noway - USNI News
Marine Corps Investigation Into MV-22B Osprey Crash in Noway
final_in_mv-22_w_attach.pdf (documentcloud.org) (48Mb) 588 pages I guess of complete report with graphics etc.
A safety paradox:-
On in hand how USN carrier operations are cited as an example of a ‘high reliability organisation’ (an organisation that has succeeded in avoiding catastrophes in an environment where normal accidents can be expected due to risk factors and complexity), but still hold a ‘human error - blame’ centred safety attitude.
Does blame contribute to high reliability, or only give the illusion of safety; or does reliability oppose safety, you cannot be both reliable and safe ?
On in hand how USN carrier operations are cited as an example of a ‘high reliability organisation’ (an organisation that has succeeded in avoiding catastrophes in an environment where normal accidents can be expected due to risk factors and complexity), but still hold a ‘human error - blame’ centred safety attitude.
Does blame contribute to high reliability, or only give the illusion of safety; or does reliability oppose safety, you cannot be both reliable and safe ?
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The finding states: "...right turn in excess of 80 degrees from which the aircraft could not recover." This is not as accurate as it could have been. There is no magic physics that suddenly arise at 75.1 degrees of bank, there is an energy maneuver deficit that arises which then has consequences at low level if the trajectory has not already been compensated for by an initial pitch up.
The MV22B was being flown at relatively low level in surprisingly good weather, and initiated a series of level turns around terrain, a hard left turn over the NATOPS limit bank, but within the flight test envelope, and then a reversal to the right at an extreme bank angle of 89 degrees. All of these turns appear to be in essentially a level attitude, however result in a washing off of airspeed and energy rapidly, however, the 22 was still at high speed at the point of impact.... so surplus energy exited, it was just not working for the crew.
The flight was operating above the planned KCAS for low level ops by 39KCAS, 259 v 220... which alters the turn radius some... as does the assessed 29kts of tailwind that existed at the time, giving a GS of near 290kts entering the final slalom.
During the last 30 seconds of flight, the crew were proximate to steep terrain features, and the potential for being disoriented from the true attitude of the aircraft in a phase of flight necessitating high levels of external scan is extreme. I am not aware that the 22 has a HUD or any HMDS giving attitude, but this has the hall marks of being a loss of SA and of disorientation. A recovery from this could have been initiated at a number of points in the event but at the point that the crew rolled to 89 degrees, the response time to reduce the RH roll and pitch to raise the FPA was lost rapidly.
I would contend that the wind was a factor, disorientation was a factor, and those point to the opportunity for training to enhanve future safety of such operations. A HMDS and or HUD would seem to be desirable. Additionally, in LL OPS in areas of terrain, formalized crew monitoring should be reinforced.It is natural for bot pilots to get their head out of the cockpit near the ground, but that may compromise SA, as is evident arose in this event. It is not a V22 centric matter, all LL OPS in rugged terrain run the risk of of loss of SA on attitude.
This was a needless accident, and certainly doesn't need a rinse and repeat cycle to learn the lesson.
The report was detailed on matters of questionable consequence, yet leaves the fundamental issue unexplored and unresolved, the crew and future V22 crews, LL jet and helo guys and girls really deserve better learning opportunities from this event.
FDR
GUESS WHAT THE BANK ANGLE IS ON THIS LAST IMAGE RECOVERED FROM THE GOPRO......
The MV22B was being flown at relatively low level in surprisingly good weather, and initiated a series of level turns around terrain, a hard left turn over the NATOPS limit bank, but within the flight test envelope, and then a reversal to the right at an extreme bank angle of 89 degrees. All of these turns appear to be in essentially a level attitude, however result in a washing off of airspeed and energy rapidly, however, the 22 was still at high speed at the point of impact.... so surplus energy exited, it was just not working for the crew.
The flight was operating above the planned KCAS for low level ops by 39KCAS, 259 v 220... which alters the turn radius some... as does the assessed 29kts of tailwind that existed at the time, giving a GS of near 290kts entering the final slalom.
During the last 30 seconds of flight, the crew were proximate to steep terrain features, and the potential for being disoriented from the true attitude of the aircraft in a phase of flight necessitating high levels of external scan is extreme. I am not aware that the 22 has a HUD or any HMDS giving attitude, but this has the hall marks of being a loss of SA and of disorientation. A recovery from this could have been initiated at a number of points in the event but at the point that the crew rolled to 89 degrees, the response time to reduce the RH roll and pitch to raise the FPA was lost rapidly.
I would contend that the wind was a factor, disorientation was a factor, and those point to the opportunity for training to enhanve future safety of such operations. A HMDS and or HUD would seem to be desirable. Additionally, in LL OPS in areas of terrain, formalized crew monitoring should be reinforced.It is natural for bot pilots to get their head out of the cockpit near the ground, but that may compromise SA, as is evident arose in this event. It is not a V22 centric matter, all LL OPS in rugged terrain run the risk of of loss of SA on attitude.
This was a needless accident, and certainly doesn't need a rinse and repeat cycle to learn the lesson.
The report was detailed on matters of questionable consequence, yet leaves the fundamental issue unexplored and unresolved, the crew and future V22 crews, LL jet and helo guys and girls really deserve better learning opportunities from this event.
FDR
GUESS WHAT THE BANK ANGLE IS ON THIS LAST IMAGE RECOVERED FROM THE GOPRO......
Last edited by fdr; 16th Aug 2022 at 22:51.
Further points re report;
The report notes that the crew appeared to reduce the power levers (however described...) during the final maneuvering. The comment is made that this was an apparent attempt to reduce the radius of turn... (paraphrasing... ) If the AAB considers that in a high energy turn it is necessary to reduce power to the thrust/lift system, then perhaps I have entered a parallel universe.
This accident occurred as the crew for various reasons maneuvered hard causing a descent that impacted the ground, which therefore means that the attitude in entering the turn was too low to maintain height. The aircraft had sufficient energy at the speed and full power to do a pull up and some roll to avoid the terrain; they didn't pull up they did a turn that resulted in a descent.
That raises two learning points.
1. at relatively high speed, the aircraft could have been pitched up to reduce the airspeed and ground speed, and permitting a high bank angle to have been entered to clear the terrain. That still needs as much power as possible, the crew need the vertical vector, and that comes from converting kinetic energy to the potential energy case. The gains from doing that is to reduce the terrain expanse in front of the crew to clear, to reduce the radius of turn and to avoid getting into a high sink condition. This crew needed to do an escape manoeuver, and did not, they tried a level turn that could not be maintained level, to which the outcome was further degraded by pulling off power thus increasing the resultant descent rate.
2. In ACM, it is conceivable that the energy state of an aircraft may make it advantageous to reduce thrust momentarily where the entry to the maneuver is well above corner speed, and for whatever reason, the option to trade off speed to height does not exist, in that case, a reduction in power may assist get to corner speed, and then the power is likely to be needed to return to max power again unless the aircraft is in a downward vertical path, but even then it is quite possible to be descending, pulling max rate and slow down unless power is added.
It is disconcerting that the fundamental handling matters that come out of even a cursory reading of this report seem to be missed by the command of this operation. None of this is magic, it is evident in the report as it stands, and the opportunity to increase fleet safety is additionally self evident. If it is not, then command is welcome to reach out for some suggestions as to what to do to increase the operational reliability of their program.
This accident is depressing enough without the addition of a report that seems to miss the mark in it's assessments and recommendations.
Teach the guys n girls to confidently operate their equipment, that gives better operational capability and reduce the unnecessary tragic losses of young crew and of a valuable operational asset.
FDR
The report notes that the crew appeared to reduce the power levers (however described...) during the final maneuvering. The comment is made that this was an apparent attempt to reduce the radius of turn... (paraphrasing... ) If the AAB considers that in a high energy turn it is necessary to reduce power to the thrust/lift system, then perhaps I have entered a parallel universe.
This accident occurred as the crew for various reasons maneuvered hard causing a descent that impacted the ground, which therefore means that the attitude in entering the turn was too low to maintain height. The aircraft had sufficient energy at the speed and full power to do a pull up and some roll to avoid the terrain; they didn't pull up they did a turn that resulted in a descent.
That raises two learning points.
1. at relatively high speed, the aircraft could have been pitched up to reduce the airspeed and ground speed, and permitting a high bank angle to have been entered to clear the terrain. That still needs as much power as possible, the crew need the vertical vector, and that comes from converting kinetic energy to the potential energy case. The gains from doing that is to reduce the terrain expanse in front of the crew to clear, to reduce the radius of turn and to avoid getting into a high sink condition. This crew needed to do an escape manoeuver, and did not, they tried a level turn that could not be maintained level, to which the outcome was further degraded by pulling off power thus increasing the resultant descent rate.
2. In ACM, it is conceivable that the energy state of an aircraft may make it advantageous to reduce thrust momentarily where the entry to the maneuver is well above corner speed, and for whatever reason, the option to trade off speed to height does not exist, in that case, a reduction in power may assist get to corner speed, and then the power is likely to be needed to return to max power again unless the aircraft is in a downward vertical path, but even then it is quite possible to be descending, pulling max rate and slow down unless power is added.
It is disconcerting that the fundamental handling matters that come out of even a cursory reading of this report seem to be missed by the command of this operation. None of this is magic, it is evident in the report as it stands, and the opportunity to increase fleet safety is additionally self evident. If it is not, then command is welcome to reach out for some suggestions as to what to do to increase the operational reliability of their program.
This accident is depressing enough without the addition of a report that seems to miss the mark in it's assessments and recommendations.
Teach the guys n girls to confidently operate their equipment, that gives better operational capability and reduce the unnecessary tragic losses of young crew and of a valuable operational asset.
FDR
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No clue if this will be helpful. MV-22B Tiltrotor NATOPS Pilot's/Aircrew Pocket Checklist PDF 01 Oct 2006: (4.3Mb)
https://www.docdroid.net/4Yletzs/bel...-checklist.pdf
https://www.docdroid.net/4Yletzs/bel...-checklist.pdf
JD and fdr, may be of interest, "Evaluation of V-22 Tiltrotor Handling Qualities in the Instrument Meteorological Environment".
https://trace.tennessee.edu/cgi/view...t=utk_gradthes
https://trace.tennessee.edu/cgi/view...t=utk_gradthes
JD and fdr, may be of interest, "Evaluation of V-22 Tiltrotor Handling Qualities in the Instrument Meteorological Environment".
https://trace.tennessee.edu/cgi/view...t=utk_gradthes
https://trace.tennessee.edu/cgi/view...t=utk_gradthes
Surprised that a current inventory NATOPS is on eBay or similar in the public domain. Please note the OPNAVINST policy.
Spaz's reference gives an inferred stall speed around 100KCAS, and an explicit stall speed around 100KCAS too, @ zero bank angle for a weight of 40KLBS. The ruff ZFW is around 31.8KLBS, [unclass] add 4 people, coffee, sandwiches, 11.8- ~ 6.0 gas.... somewhere south of 40... That's about 4g pull available... The reported 70 bank limit is rational for normal maneuver then to avoid bending bits, and a reported NATOPS 60 degree bank limit in SQN ops is also good for normal ops. (at 90.... y'all are coming down at 9.81m/sec.sec... even that should not be catastrophic, it is just has a vector going in the direction of down about... -6 deg after first second... -15 at t=2, etc to around -45 at t=10 seconds... assuming no reduction in bank and no pitch to recovery... ) Those FPA decays will start to get eye watering in less than 5 seconds (ruff figgers) if not corrected at low level.
Curiously, the aircraft was well within the probable OGE hover envelope, but of course the nacelles are not at 90-97 position, they are in the 0 or near 0 position, so thrust alone could support the aircraft if they pitched up sufficiently, untll the oil system, fuel system etc call time out which would happen well before that, but, still, you can pitch up to a relatively high ANU and not expect the donks to go silent. A 4 g pull was readily available, and could have been sustained at a reduced level to somewhere north of 45 degrees, unless Bell and co forgot to put in collectors in the gas tanks. Speed bleed would be rapid, but then the props can probably support the plane to 10,000' OGE, so there would have been a viable pitch up maneuver available, and some roll once the FPA was upward, the decay in FPA is straightforward to determine, and gave some time to turn, had a pitch up been conducted first. I don't drive V-22's I am helo and low level jet experienced but overall I don't see that this was an accident that had to occur; the fault appears to be in the training or experience to permit the driver to achieve a recovery maneuver, and underlying it all, the tailwind compressed the time slightly and complicated the geometry, but there was every opportunity for a loss of orientation, which added to the bank angle that apparently occurred.
Now, over banking does help rate if you can avoid the ground, not an ideal attitude at 500'....
The crew, family, Corps and Navy deserve better learning points than a collection of files of process on a kinetic event.
Please note: No former coup leader was harmed in obtaining the analysis above, if needed, please raid the following address:
1100 S Ocean Blvd, Palm Beach, FL 33480, United States
The Masters Thesis document on the HQ of the V-22 is interesting and has some items of interest for doing approaches, but there is nothing in the handling report that suggests other than an interesting aircraft. HQR's are better than I expected them to be, having a bit 'o wing obviously is what the maker intended. The thesis does give some interesting images of the cockpit that existed for the V-22, and it is not a bad shack, however, there seems to be a glaring item missing and that is there is no obvious wind vector display or even GS, and for a machine that has had so much fun with VRS, that seems to be a missing bit of information that is of more than passing interest. For TACOPS, that info is quite critical, a RTT maneuver makes some difference if you know where the wind is at, so does rapid stops etc. I will assume that the USN would have CERTAINLY added such a feature to the PFD/ND out of an overwhelming sense of care for the people inside their toys.
Last edited by fdr; 17th Aug 2022 at 06:34.
There doesn't seem to be any movement on training V-22B drivers to be able to achieve maximum performance from their machine through using the vertical. Seems a pity, as 4 guys otherwise died without a simple learning point being taken to heart. by the USMC. They are not alone in this area however, we have seen firebomber aircraft smoke in when an escape manoeuvre was available until close to the final curtain. We used to teach this in low flying in high terrain, and we still teach the same in rotary wing low level ops/ag flying. The V-22 has a best of both worlds thing going on, that it can pull some g supported by the wings, and gain high thrust at low speeds to minimise energy loss at apogee of an out of plane turn back. not exactly a torque turn or a pedal turn, but somewhere between a high powered prop and a rotorcraft.
