Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Jet - crash - who is guilty

  1. the technician

    1 vote(s)
    14.3%
  2. the crew chief

    3 vote(s)
    42.9%
  3. the pilot

    1 vote(s)
    14.3%
  4. the management

    2 vote(s)
    28.6%
  5. the manufacturer

    0 vote(s)
    0.0%
  1. Feb 23, 2010 #1
    Let's do an exercise in safetly management and sound judgement.

    In some countries somebody is considered guilty if there is an accident with casualties. Maybe we could do a little court marshalling to find out who is guilty in the following mishap, It pertains a take off crash of some Air Force jet of the type ‘Voodoo’ (F-101) way back in the 1950's.

    I read about it years ago and tried to find it back on internet, but googling failed. So no links, just from how I recall it.

    The jet started the take off roll and accelerated as per normal but it never got airborne. Eventually the pilot was trying to bring the aircraft to a stop at the last moment, by deploying the drag chute. I can’t recall if it had a tail hook and if the runway had an arrester cable installed, but anyhow, all failed and the aircraft departed the end of the runway at high speed and dipped into a stream where it came to a full stop. The pilot attempted to exit the cockpit but the canopy was jammed due to the deformation in the crash and most unfortunately he drowned before the rescue party could free him.

    The safety board was riddled initially, every piece of the aircraft was fully functional until impact, there was only one fishy thing, which made it possible to find the most probable cause. I summarize the elements that played a role in the development of the mishap in chronological order:

    1. There was a major exercise ongoing on the air base, that got all priorities

    2. The mishap aircraft was to be flown to a commercial airfield where it would go to a civil contractor for a modification.

    3. The aircraft contained a secret aiming device that had to be removed prior to it going to the industry.

    4. A specialist went to the aircraft to remove that gadget but when he actually had the apparatus in his hands pulling it out the avionics bay, he was called away for a high priority repair on another aircraft to be ready for the exercise. It was the shouting now-drop everything-immediate type of call.

    5. Eventually he returned to the aircraft to finish up, close up the access doors and collect the tools.

    6. The crew chief responsible for the aircraft, prepared it for the flight next. He was highly regarded, a real can-do person, he realized the stress the technician was in, when he did that job and decided to check if everything was done correctly. However, in doing so, he discovered that there was still an open tube in that avionics bay. It was an air tube of the pitot static system, which is the main input for the pneumatic airspeed indicator. This is where the gadget had been connected to, since it also needed the dynamic/ram air pressure input. The technician should have plugged that during that job he did.

    7. As there was quite a bit of time pressure, and he could not find a dedicated plug for that hole nor could he recall the technician, the crew chief decided to repair it himself provisionally. This was not unusual; actually it was is known as ‘battle damage repair’ and he took some duct tape and closed off the hole.

    8. A young inexperienced pilot had to do the transition flight to the civil airfield. This was not standard procedure, but all the experienced pilots were occupied in the exercise.

    Those are the bare facts leading to the accident which was deducted to be as follows:
    As the jet was accelerating on the runway, the dynamic air pressure building up in the tube, for the airspeed indicater, started to leak away along the duct tape, as it was not sealed air tight. The reduced pressure caused the airspeed indicator to indicate a lower value than the real speed.

    Most likely, the pilot had no idea what was going on and waited with the rotation for flight for the airspeed to hit the rotation-take off speed mark. But this never came, so he finally aborted the take off attempt, but obviously too late.

    So, who was ultimately responsible for the death of the pilot?

    A: The technician, who did not do a proper job and who left that hole open?

    B: The crewchief for a non standard repair job?

    C: The pilot for the inability to judge that the airspeed outside and inside were mismatching?

    D: The management of the air base for, mixing routine maintenance jobs with the high priority exercise?

    E: The aircraft manufacturer for not providing an emergency exit possibility in case of a jammed canopy.

    Obviously, there is no canned preset good answer. It’s just about your judgement, why somebody is to blame. It would also be interesting to learn about your recommendation to prevent this kind of mishaps in the future.
     
  2. jcsd
  3. Feb 23, 2010 #2

    FredGarvin

    User Avatar
    Science Advisor

    Re: Jet - crash - who is guilthy

    Voodo's. Man what a cool aircraft.

    The list of people accountable is long on this one so I didn't vote in the poll. I can't say there wasn't a person who did not contribute to the accident.

    So let's start at the top:
    - Squadron Commander: Not staying on top of flyability status and maintaining even work flow for his subordinates and for lack of supervision. Also, approving non-standard procedures without adequite supervision.

    - Newb Pilot: By the sounds of it initiated abort takeoff procedures too late in the take off roll.

    - Specialist: Failed to complete job as outlined in manuals and negligence in conduction of duties.

    - Crew Chief: Negligence in performance of required duties.

    Now, the one question I have: In my experience, this maintenance action would have, most likely, degraded the status of the aircraft to non-flyable since it involved the direct disconnection of an instrument required for safe flight. This would have required a technical inspector's sign off prior to allowing the aircraft into flight status. Did this happen? If it did not, then I again, pin that on the crew chief. He is responsible for categorizing maintenance activities and ensuring the aircraft is flyable.

    I would have to see the manual for the instrument involved to lay anything at the feet of the manufacturer. The issue of the jammed canopy may have a leg to stand on, but was probably the norm in the day.
     
  4. Feb 23, 2010 #3
    Re: Jet - crash - who is guilthy

    I recall nothing about that in the original story. Nowadays any action on pitot static systems requires a calibration check. Maybe that was a result of this mishap. Anyway, the secret gadget (not required for safe flight) was disconnected from the pitot tube but the hole was left open as the technician did not install the dedicated plug. And no doubt that the paperwork was done.
     
  5. Feb 23, 2010 #4
    Re: Jet - crash - who is guilthy

    I am going to go with the crew chief. It appears that he was not directly involved with the high priority exercise, and could have found ample time to fix the problem without resorting to duct tape.
     
  6. Feb 23, 2010 #5
    Re: Jet - crash - who is guilthy

    Duct tape was a clearly inadequate method of repair of such a crucial instrument as the outside airspeed indicator, and this method would've led to more crashes if applied often. We would have to examine maintenance procedures in place at the base. Was that standard practice? Whose call was it to authorize this kind of repair and deem the plane fixed with duct tape flyable?
     
  7. Feb 23, 2010 #6
    Re: Jet - crash - who is guilthy

    No, crewchiefs are responsible for their aircraft. Aircraft and pilots fly in the exercise. Everybody on the base is working for the exercise. Depending on man/woman power, a crewchief can be responsible for more than one aircraft in sequence on a given day. You can safely assume that he had only two choices, either fix it now or cancel the flight.
     
  8. Feb 23, 2010 #7

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    Re: Jet - crash - who is guilthy

    Crew chief. That was a lame fix.

    Management (i.e. - commander, et al) contributed, but not in the way that may seem obvious. Allowing the exercise to interfere with real world operations isn't the problem, since, presumably, the exercise isn't going to stress flight operations more than an actual combat situation would. If the exercise operations are interfering with real world operations to the extent that you had an unnecessary fatality, then combat operations are going to stress flight operations badly enough to cause unnecessary fatalities.

    Things need to be changed, but better to have an unnecessary fatality during an exercise than during combat ops when both the pilot and plane are going to be a bigger loss. For one thing, there has to be big enough emphasis on safety that the crew chief would feel confident in bringing that flight to a halt, if necessary.

    Something similar happened to our satellite tracking antenna years ago. A young airman was supposed to do a PMI (preventive maintenance inspection) on the antenna and accidently broke the helix while doing the PMI. He superglued it back together and superglue is just not a great conductor. He went home for the weekend after completing the PMI and the rest of us endured the weekend from hell. The antenna kind of worked/almost worked; in fact could pass many tests, but it just didn't have the power it used to. As a result, the weekend maintenance personnel searched for and corrected numerous "problems" and still the antenna would fail every time we used it on a real satellite. Like I said, that antenna just didn't have the same power it used to - and who would ever think to inspect the antenna to see if the helix was broken and superglued back together?!

    Monday morning, the airman comes back to work, looks through the log, and starts thinking, "Uh oh". It probably took a little courage to ask his supervisor what impact supergluing the antenna helix back together would have.
     
  9. Feb 23, 2010 #8
    Re: Jet - crash - who is guilthy

    The dynamic pressure in the pitot static tubes is not very big, if the duct tape had been applied air tight, then it should have worked. It's not likely that anybody had even considered this exact type of repair, but don't forget that we're talking about a time shortly after WW-II where the mission had high priority, and you needed to get that aircraft in the air, one way or the other - improvise. If it flew, you did well and no questions were asked, if it crashed, just, tough luck.
     
  10. Feb 23, 2010 #9
    Won't be a popular opinion but the pilot is ultimately responsible for the aircraft.
     
  11. Feb 23, 2010 #10
    Re: Jet - crash - who is guilthy

    If that was the official policy, some crashes were inevitable and blame should not be placed with anyone (except maybe with some high-ranking general who instituted the policy, even though it was peacetime and sacrifices were not necessary).

    To confirm, I would have liked to interrogate the crew chief to understand his frame of mind. Was he aware that his "fix" could've caused malfunction of the airspeed indicator? Did he have the authority to ground the plane pending the proper repair? Would he fear prosecution if he did so?
     
  12. Feb 23, 2010 #11

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Re: Jet - crash - who is guilthy

    Making an air-tight seal on an open tube with duct tape, or any kind of tape for that matter (barring Teflon tape), is very difficult to do (in my experience). There's always a fine gap running along the starting edge of the tape where the second layer climbs over the first one.
     
  13. Feb 23, 2010 #12

    russ_watters

    User Avatar

    Staff: Mentor

    Yes.
    Yes.
    No.
    Yes.
    No.
    Recognize how critical the pitostatic tube is and don't do a ghetto-fab repair. And test it.
     
  14. Feb 23, 2010 #13

    russ_watters

    User Avatar

    Staff: Mentor

    Re: Jet - crash - who is guilthy

    Also, how does duct tape perform in sub-zero temperatures of high altitude flight? This pilot never found out, but I can't imagine very well.
     
  15. Feb 23, 2010 #14

    russ_watters

    User Avatar

    Staff: Mentor

    A pilot (nor anyone else in a similar situation, such as a car driver) can/is not required by ethics or law to be able to control things that are not reasonably within his contro.
     
  16. Feb 24, 2010 #15
    Anyway, the moral of the story, I had in mind is to point out the accident chain, a sequence of events that accumulates into an accident. There isn't a sole cause. If you remove any one of the 8 points in the sequence of the OP, the accident would not have had to happen. And even if there had an adequate redundant escape system, the accident would not have been fatal.

    So my two cents, whodunnit? All. Who is responsible? all are with the exception of the manufacturer, who simply designs a (militairy) aircraft according to the specifications of the customer. But who crosses the responsibility burden the most? That's the management/squadron/wing/base commander. There is often a lot of strain between safety and production output. The commander wants results now, we have to win a (simulated) war, for G.. sake, no time for distractions. The priority should have been on flight safety as it should be all the time. That was basically what was wrong. The ferry flight to the contractor should not have been planned during the exercise and the technician should not have been called away, while on the job. The crewchief should have pulled the emergeny brakes upon discovery of the open hole.

    And the lesson for all is, try to recognise an accident chain building up and stop it and that's not only for flying. That's also far better than assigning a scapegoat and have a wrong feeling of justice.
     
  17. Feb 24, 2010 #16

    FredGarvin

    User Avatar
    Science Advisor

    There is one other aspect to this that should be mentioned. That is that when the word "blame" is used, it connotates an intent to cause harm or damage. I can't say that that appeared here anywhere. People will lose jobs over this kind of F-up in today's military. The 1950's? Who knows?
     
  18. Feb 24, 2010 #17

    lisab

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Good point. Current safety culture urges a search for "root causes," not blame.
     
  19. Feb 24, 2010 #18
    That reminds me of a civilian crash that I saw on tv the other night. The airplane never lifted off and they blamed the pilots for failure to lower the flaps. Flaps were up, warning indicator never sounded, however. Voice recorder playback had the voice of the co-pilot stating: two fiften in the green, meaning he had an indicator showing the flaps down and in the green. So, the inspectors said the co-pilot didn't bother to really look at it. The plane had been delayed for over an hour on the ground and they didn't maintain a sterile cockpit during the delay. But my question is this: There is a confirmation for the co-pilot's verbal read out - the warning sensor did not catch that the flaps were NOT down, either. So, was the sensor that gives the green light on the flaps incorrect and thus it gave an incorrect reading to the warning system, such that there was no warning sounded? That makes far more sense to me. There is nothing to back up that the co-pilot misread or failed to properly read the flap indicator. The model they were flying put the pilot's so far ahead of the wing that they could not visually confirm flap position. I would state, however, that in my opinion (but not having flown the particular model) an experienced crew should "feel" the difference in the acceleration and handling IF the flaps were not down. That said, however, I don't know that particular aircraft and it may well be that it would not be noticeable. After all 15 degrees of flap isn't a lot on some aircraft. But my point is that they never mentioned any connection between the co-pilot's readout and the lack of a warning indicator which should have sounded if the flaps weren't properly set. And that leads me to believe that there was a false positive reading given to the instruments and the crew. And I wonder why that was not explored further.
     
  20. Feb 24, 2010 #19
    As Grandpa Pettibone would say: Looks like the pilot was to worried about a gauge inside the his cockpit and plumb forgot to look out his window and fly the plane.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Jet - crash - who is guilty
  1. Guilty Pleasures (Replies: 46)

  2. Feeling a bit guilty (Replies: 8)

Loading...