B52 crash off Guam
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Risbutler,
Please remember that both the USAF and USA use full time accident investigators that do not necessarily have experience on the particular type/model series vice the USMC/USN model where everyone is from the particular type/model series with the requirement of only one being a trained accident investigator. Very different results though I have seen reports from both processes that immediately raised my BS flag as being impossible.
S/F, FOG
Please remember that both the USAF and USA use full time accident investigators that do not necessarily have experience on the particular type/model series vice the USMC/USN model where everyone is from the particular type/model series with the requirement of only one being a trained accident investigator. Very different results though I have seen reports from both processes that immediately raised my BS flag as being impossible.
S/F, FOG
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{Ref: risbutler #22}
...yes, seems odd the Board President found the "cause" of the mishap to be "a mis-positioning of the stabilizer trim".
The obvious question is what caused that stab-trim mis-positioning -- which would be a closer answer to the actual root cause of the crash.
USAF used to be extremely fussy about determining & formally using the word "CAUSE" in any mishap report, so that corrective action could pinpoint the fundamental problem in a sequence of events.
The Board states they could not determine the reason for the improper trim position-- which obviously means they could NOT determine the mishap Cause. No 'cause' should therefore be stated in the formal report.
And I agree that power-settings should have been mentioned somewhere in the report discussion.
Your speculated uncomfortable bunt descent is also of concern since the whole purpose of this mishap sortie was a flyover/airshow. We know from many decades of mishaps with such formal & informal displays that some pilots have a tendency to exceed normal safety considerations.
...yes, seems odd the Board President found the "cause" of the mishap to be "a mis-positioning of the stabilizer trim".
The obvious question is what caused that stab-trim mis-positioning -- which would be a closer answer to the actual root cause of the crash.
USAF used to be extremely fussy about determining & formally using the word "CAUSE" in any mishap report, so that corrective action could pinpoint the fundamental problem in a sequence of events.
The Board states they could not determine the reason for the improper trim position-- which obviously means they could NOT determine the mishap Cause. No 'cause' should therefore be stated in the formal report.
And I agree that power-settings should have been mentioned somewhere in the report discussion.
Your speculated uncomfortable bunt descent is also of concern since the whole purpose of this mishap sortie was a flyover/airshow. We know from many decades of mishaps with such formal & informal displays that some pilots have a tendency to exceed normal safety considerations.
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Delaney,
Since the DoD are being forced together the use of cause is mandated. The USAF and USA tried to eliminate the whole concept of privilege which the Naval services fought and again the compromise doesn't satisfy anyone except those who want purple homogeneity at all costs.
At issue with the jointness is the creation of better data bases that are searchable. That means causes have to be declared and then placed into pre-determined categories so that data fields are auto populated. I recently had to write a mishap report that was inaccurate in it's conclusions due to the nature of the system now in place. My only recourse was the additional comments block where I could correct factual errors (lost time doesn't count if not consecutive, the casual factor didn't honestly fit into any pre-determined category, etc.)
Having stated the above there is a USAF Col. who still owes me a 25 y/o bottle of Talisker over a mishap report about ten years ago that people disagreed with and the USAF later had to completely re-write.
Basically two choices; either the new system forced bad data which is happening, or incompetent report which has happened. Remember that the 1st link is a public affairs take and the 2nd is not the full FOUO report.
S/F, FOG
Since the DoD are being forced together the use of cause is mandated. The USAF and USA tried to eliminate the whole concept of privilege which the Naval services fought and again the compromise doesn't satisfy anyone except those who want purple homogeneity at all costs.
At issue with the jointness is the creation of better data bases that are searchable. That means causes have to be declared and then placed into pre-determined categories so that data fields are auto populated. I recently had to write a mishap report that was inaccurate in it's conclusions due to the nature of the system now in place. My only recourse was the additional comments block where I could correct factual errors (lost time doesn't count if not consecutive, the casual factor didn't honestly fit into any pre-determined category, etc.)
Having stated the above there is a USAF Col. who still owes me a 25 y/o bottle of Talisker over a mishap report about ten years ago that people disagreed with and the USAF later had to completely re-write.
Basically two choices; either the new system forced bad data which is happening, or incompetent report which has happened. Remember that the 1st link is a public affairs take and the 2nd is not the full FOUO report.
S/F, FOG
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Au contraire, there IS extensive pilot input into the report. Apart from one of the Board members being a pilot, there was extensive simulator runs done - that was the pilot input. Even if the President had flown nothing more than a Tiger Moth, the discussions the Board would have had with the pilots flying the simulator runs would enable them to reach sensible conclusions.
Having read through the whole document, the Board reaches a reasonable conclusion. The only thing the MP could have done was to crank on 120 degrees of bank, accept the loss if his engines, but got the aircraft into a level position to allow the crew to eject. I don't think that that would have occured to the average pilot sitting in the cockpit with seconds to react - armchair piloting is wonderful.
In a UK Board that I conducted as President [take-off crash] I enlisted the help of an AIB behavioural scientist. He explained that it takes seconds for the pilot to identify that there IS a problem, seconds to IDENTIFY the problem, seconds to work out a course of action and seconds to actually carry out those actions - can be as much as 30 seconds from start to finish. Even more if the problem is unusual and not routinely practiced in the simulator.
So a trim runaway would have doomed the crew right from the start...
It happened on the Canberra until the double pole switch was introduced for the elevator trim.
Having read through the whole document, the Board reaches a reasonable conclusion. The only thing the MP could have done was to crank on 120 degrees of bank, accept the loss if his engines, but got the aircraft into a level position to allow the crew to eject. I don't think that that would have occured to the average pilot sitting in the cockpit with seconds to react - armchair piloting is wonderful.
In a UK Board that I conducted as President [take-off crash] I enlisted the help of an AIB behavioural scientist. He explained that it takes seconds for the pilot to identify that there IS a problem, seconds to IDENTIFY the problem, seconds to work out a course of action and seconds to actually carry out those actions - can be as much as 30 seconds from start to finish. Even more if the problem is unusual and not routinely practiced in the simulator.
So a trim runaway would have doomed the crew right from the start...
It happened on the Canberra until the double pole switch was introduced for the elevator trim.
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FJJP
As you mention it, I will gladly defer to your experience of this sort of proceeding. Although as you have not done so yet, can you say what you find to be unreasonable about the reservations that I have voiced from my armchair ?
I too can see that there is a pilot on his board and that experienced pilot instructors were involved in the simulation. What I do not see is the pilot’s point of view in the discussion. Did you have two lawyers on your board ?
In place of common airmanship, the report gives great prominence to the table at Figures 3 and 5. It fails to note the anomalies contained within it.
The simulation fails to replicate the observed flight profile illustrated in Figure 2. Boeings naturally demur at simulation outside the flight envelope, especially when (as it seems to me) Figure 2 tells us the aircraft goes mach-critical before it drops out of sight of the radars. That the test crew cannot match speeds and heights in the first half of the descent suggests that the simulator might be no more suited to this exercise than (if it as old as the airframes) it should be.
Second, why the presumption that the runaway was detected only as the aircraft had accelerated to the run-in speed ? Presumably the runaway would be initiated by a trim selection, rather than arising spontaneously. The PF can be expected to take little bursts of trim as he sets the desired dive angle and as the speed increases. If he gets more than he has selected, he will know it at once.
If I were briefing this manoeuvre, I would have gone for a descent at 300 kts (the flypast run-in speed) and a descent at 5000 ft/min which would get the aircraft to run-in height half way down the 30 nm inbound track. That works out at 8 or 9 pitch ND. Whether through clumsy handling or runaway trim, at 25 secs the PF should know the aircraft has pitched too far. That is when the captain should get on the case – unless a bit of a hairy dive was what the pilots had agreed on.
What the table shows is that at this point the PF takes off a bit of bank and then rolls back in again. Why ?
At 35 secs, as the speed builds, clearly there is a deliberate recovery action being taken; the wings are rolled level at approaching twice the rate of roll used originally. Although the speed is galloping through Vne, the nose comes up a bit at this stage and stays there for a calculated 15 secs before it drops away. Is this when manual trim is being used, if it is used at all (although of course this is time enough to reverse the stabiliser into a positive setting) ? Or are we to suppose that, with two pairs of boots on the instrument panel, that is the extent of the elevator’s authority in relation to the errant stabiliser ? In the last part of its dive this aircraft has stopped pitching down. At least that is what Figure 3 says. The lost Canberras were thought to bunt all the way, if they started with enough altitude.
While the 120 deg bank is what we might have resorted to if the Canberra’s dipole switch let us down, the idea of doing so in a B-52 is just ever so slightly theatrical.
The B-52 has enough bells-and-braces in its powered trim control, plus the cut-out and a manual selector as well. The pilots’ fingers would have wandered past these emergency switches every trip. Surely, self-preservation would have kicked in at the expense of “Recognise , Confirm, Bold Face, Reassess” ? – if runaway really was the problem.
Still, with your experience no doubt you are right to find the president’s conclusions reasonable. But I would still like to have been told whether or not the aircraft was under power throughout its last dive.
As you mention it, I will gladly defer to your experience of this sort of proceeding. Although as you have not done so yet, can you say what you find to be unreasonable about the reservations that I have voiced from my armchair ?
I too can see that there is a pilot on his board and that experienced pilot instructors were involved in the simulation. What I do not see is the pilot’s point of view in the discussion. Did you have two lawyers on your board ?
In place of common airmanship, the report gives great prominence to the table at Figures 3 and 5. It fails to note the anomalies contained within it.
The simulation fails to replicate the observed flight profile illustrated in Figure 2. Boeings naturally demur at simulation outside the flight envelope, especially when (as it seems to me) Figure 2 tells us the aircraft goes mach-critical before it drops out of sight of the radars. That the test crew cannot match speeds and heights in the first half of the descent suggests that the simulator might be no more suited to this exercise than (if it as old as the airframes) it should be.
Second, why the presumption that the runaway was detected only as the aircraft had accelerated to the run-in speed ? Presumably the runaway would be initiated by a trim selection, rather than arising spontaneously. The PF can be expected to take little bursts of trim as he sets the desired dive angle and as the speed increases. If he gets more than he has selected, he will know it at once.
If I were briefing this manoeuvre, I would have gone for a descent at 300 kts (the flypast run-in speed) and a descent at 5000 ft/min which would get the aircraft to run-in height half way down the 30 nm inbound track. That works out at 8 or 9 pitch ND. Whether through clumsy handling or runaway trim, at 25 secs the PF should know the aircraft has pitched too far. That is when the captain should get on the case – unless a bit of a hairy dive was what the pilots had agreed on.
What the table shows is that at this point the PF takes off a bit of bank and then rolls back in again. Why ?
At 35 secs, as the speed builds, clearly there is a deliberate recovery action being taken; the wings are rolled level at approaching twice the rate of roll used originally. Although the speed is galloping through Vne, the nose comes up a bit at this stage and stays there for a calculated 15 secs before it drops away. Is this when manual trim is being used, if it is used at all (although of course this is time enough to reverse the stabiliser into a positive setting) ? Or are we to suppose that, with two pairs of boots on the instrument panel, that is the extent of the elevator’s authority in relation to the errant stabiliser ? In the last part of its dive this aircraft has stopped pitching down. At least that is what Figure 3 says. The lost Canberras were thought to bunt all the way, if they started with enough altitude.
While the 120 deg bank is what we might have resorted to if the Canberra’s dipole switch let us down, the idea of doing so in a B-52 is just ever so slightly theatrical.
The B-52 has enough bells-and-braces in its powered trim control, plus the cut-out and a manual selector as well. The pilots’ fingers would have wandered past these emergency switches every trip. Surely, self-preservation would have kicked in at the expense of “Recognise , Confirm, Bold Face, Reassess” ? – if runaway really was the problem.
Still, with your experience no doubt you are right to find the president’s conclusions reasonable. But I would still like to have been told whether or not the aircraft was under power throughout its last dive.
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FJJP,
I have been the senior member on a couple of USMC boards and participated on a few more. I have worked with all three service mishap boards.
Notice that the senior member is a TacAir type pilot vice a heavy bomber and a BGen while the pilot is a Maj, as is the navigator. Assuming that the pilot is of the heavy bomber pilot persuasion as is the navigator, how much of their input was actually translated into TacAir then back into heavy bomber? Remember there is no USAF requirement to have anybody on the board be from the particular community in question, I can think of a HC-130 and a F-16 mishap where that was the case.
Simulators are far from perfect in depicting mishaps. Hornets were unrecoverable from falling leafs, Ospreys weren't susceptible to asymmetrical ring vortex, and Herks couldn't barrel roll in simulators until proven in real life. At best the simulator is a rough approximation based on different imprecise data points.
The medical representative (along with the safety officer) would have at least a familiarization course on the behavioral sciences and part of the check list for all services is to consult with the specialist.
S/F, FOG
I have been the senior member on a couple of USMC boards and participated on a few more. I have worked with all three service mishap boards.
Notice that the senior member is a TacAir type pilot vice a heavy bomber and a BGen while the pilot is a Maj, as is the navigator. Assuming that the pilot is of the heavy bomber pilot persuasion as is the navigator, how much of their input was actually translated into TacAir then back into heavy bomber? Remember there is no USAF requirement to have anybody on the board be from the particular community in question, I can think of a HC-130 and a F-16 mishap where that was the case.
Simulators are far from perfect in depicting mishaps. Hornets were unrecoverable from falling leafs, Ospreys weren't susceptible to asymmetrical ring vortex, and Herks couldn't barrel roll in simulators until proven in real life. At best the simulator is a rough approximation based on different imprecise data points.
The medical representative (along with the safety officer) would have at least a familiarization course on the behavioral sciences and part of the check list for all services is to consult with the specialist.
S/F, FOG
