25 thoughts on “747 Down”

  1. My wife received a short phone call this morning from our son in Afghanistan. He said that he had a close call but he’s OK. He’s stationed at Kandahar but, as I understand it, he travels to other areas. I wonder if he was at Bagram on Monday…

  4. A load shift could do it, but so could other things. One possibility that comes to mind is a failure to deploy flaps and slats for takeoff. However, I think I see deployed flaps.

    It’d be worse if the plane was doing a high angle of attack departure (done due to missile concerns there, I think I recall). Maybe multiple engine out in that kind of departure could do this? Compressor stall? Bird ingestion?

    I also have to comment on the driver of the vehicle with the dash cam. It looks to me like he used his vehicle to block the road for a few moments, and they drove towards the crash and fire, probably looking for people in need of help. He’s got to be military IMHO; they head towards danger when there might be people to save, even if it means (as in this case) driving to the edge of a fireball. (and I doubt he knew if there might be more blasts, such as if the plane was carrying ammo). Most others would head the opposite direction after a near miss from a crash like that. I think the guy deserves a commendation.

      1. No I doubt it. A flame-out would mean you make a controlled crash landing.

        Here the angle of attack of the a/c went bonkers and all lift was killed. There was something that prevented them from getting the nose down (power on stall recovery is something you learn as a private pilot for just this situation.). Maybe a cargo shift as suggested above or the elevator commanding went bonkers.

        1. I read something about shifting high crosswinds. Just before the plane goes straight up, you can see it shimmy to one side then the other.

  5. I think most people would drive toward the crash to see if they could save anyone. The problem in many emergencies is not too few volunteers, but too many.

  6. If it was a cargo shift, no amount of down elevator is going to drop the nose.

    One option would have been for them to cut power – which is not the instinctive move. This would have dropped the nose and maybe they could have bellied in, in a more controlled fashion. They could have played the power to control pitch a little.

    1. One option would have been for them to cut power

      Having argued with “Professional Pilots trained in 747s”, the manual says in a stall to power out of it. These arguments were in relation to the Air France 447 crash. When asked why not lower the nose (as trained in basic flight school), they all said the manual and training tells them not to do this because the 747 has sufficient power to push through. And I suspect that may be true near sea level. Air France 447 was (an A340) and Bagram is not at sea level.

    2. I don’t know how much of a pitching moment you get from power changes on the 747.

      If the speculation about shifting cargo is true, cutting power would’ve caused the airspeed to decay rapidly, causing the tail to lose effectiveness even faster. If the plane had a severely aft CG (very, very bad), then the horizontal surfaces were actually creating upwards lift. Losing effectiveness would’ve caused the nose to rise faster. It sure looks like the plane stalled. They got the wings level but were still sadly doomed.

      1. “If the speculation about shifting cargo is true, cutting power wouldā€™ve caused the airspeed to decay rapidly, causing the tail to lose effectiveness even faster.”

        The point of cutting power is that almost all a/c have a downforce on the tail for static stability. This is because the center of lift on the wing is usually behind the CG on almost all airplanes. The lift creates a nose-down moment so the tail needs to balance it with a nose-up (down-force moment). Added to that are the under-slung engines whose thrust line is, I believe, under the CG. That would tend to raise the nose as well, as you add power.

        Now it’s true that fly-by-wire a/c don’t have to have that built in because the computer takes care of it. What happens if the computer dies, I do not know. I also don’t know if that vintage 747 was fly by wire or not.

        I did look up the POH and it does say to keep power high.

        But my thought on cutting power was not to regain controlled lifting flight as most stall recoveries try to do. Rather it was to get the nose down and the fuselage somewhat level and generate a controlled crash…at that speed and alt they were not going to fly their way out of it.

        1. When the nose goes higher than expected, a pilot’s natural reaction is to push forward on the yoke (or stick). If cargo broke loose and shifted aft, the plane’s nose would get high very fast. If the CG shifted aft enough, the plane becomes unstable to the point that the tail surfaces are generating upward lift. Cutting power would slow the plane, reducing the upward lift and making the nose go even higher. Cutting power under those circumstances is counter-intuitive and may even make matters worse.

          1. “a pilotā€™s natural reaction is to push forward on the yoke (or stick). ”

            Yes that’s why I said, in my initial suggestion:

            “One option would have been for them to cut power ā€“ which is not the instinctive move. ”

            No elevator command was going to do much of anything.

            “If cargo broke loose and shifted aft, the planeā€™s nose would get high very fast.”

            Yes. And one reason is because the center of lift is now AHEAD of the CG. The CG got shifted aft (assuming the cargo broke loose).

            That means that any lift you create is going to RAISE the nose. Since you cannot counter act that with elevator (zippo moment) what is a pilot to do?

            One thing might be to reduce that torque created by the lift vector. And in fact that’s what you saw once the wing stalled – no lift – the nose dropped. Right? Speed went down…lift went down…nose went down….

            Another thing you might do is reduce the torque created by the engine thrust lines being underneath the CG. How does one do that?

            “Cutting power would slow the plane,”

            Obviously they did NOT cut power and the plane slowed to zero. What have you gained? The engines were still churning out max t/o power and pushing the nose up. Airspeed still dropped to zip anyways.

            “Cutting power would slow the plane, reducing the upward lift and making the nose go even higher.”

            Not after the center of lift moved ahead of the CG. Then the opposite happens….if you reduce lift you reduce the nose up moment.

            “Cutting power under those circumstances is counter-intuitive ……”

            So I’ve said.

            “…..and may even make matters worse.”

            Worse than what happened?

            I’m not guaranteeing they could have had a more controlled crash but it might have been an option.

          2. The key thing is if the CG shifted too far aft, the aircraft is now statically unstable, and if the CG went really aft, the time to double of the instability can quickly get too small for a pilot to handle, especially in a low speed, low control power situation. That’s why aircraft have aft CG limits. That’s also why, say, the B-2 has a full time fly-by-wire system; in some situations, the time to double due to pitch instability is less than a tenth of a second.

  7. Those of us in the air freight business really appreciate statements like: “Fortunately it was a cargo plane, and they only lost seven crew.”

    I’m confident the family and friends of the crew are thankful that only the seven crewmembers were killed. They weren’t truly important, say, like onlookers at a sporting event and I doubt we’ll see wall-to-wall coverage of these nonentities.

    And by the way, “angle of attack” does not mean pitch angle. If you people want to sound knowledgeable by using aviation terminology you should research the definitions before displaying your ignorance to the world.

    1. It’s certainly devastating for those who knew and loved the crew, but flying that airplane was their job, and a risk they willingly took (just like astronauts). I was simply pointing out that it wasn’t hundreds of passengers, as most 747s carry.

      And clearly both the pitch angle and angle of attack were way out of spec. He didn’t necessarily equate them.

      1. It’s an old story (e.g., Tigers 66). Cargo crew lives are inconsequential because their deaths aren’t a useful political tool. It’s only the happenstance of people with cellphone cams that make their crashes or late gear extensions or whatever even slightly newsworthy.

        1. Unfortunately, yes. Passengers on an airliner have a high expectation of safety. Crew members on a cargo aircraft are doing their job, which (if they’re smart) they know entails some level of risk. Truck drivers die on the highways, too. Why is this different? Only, as you say, because we managed to get spectacular video of it.

          1. Note that bus accidents almost always get significant news coverage, often national coverage, however briefly. A truck accident only gets national coverage if it shuts down a major highway for half a day after causing an epic pile up.

            I assume the bias is because the TV audience is made up of people who imagine themselves as potential passengers, not cargo pilots or truck drivers.

    2. Compared to a passenger version of the 747-400 that could’ve been carrying over 350 people, just losing 7 lives is a relatively good thing. Still, those 7 people were loved by many people and their deaths are terrible. As a private pilot, I can visualize what they were seeing in those last seconds. The only mercy was that it happened very quickly. May they rest in peace.

  8. “And by the way, ā€œangle of attackā€ does not mean pitch angle.”

    No it does not.

    But then of course, some of us who actually DO know what we are talking about know that it’s AOA and not pitch that determines whether or not you are stalled. Flying aerobatics, I’ve stalled (from being not stalled) the wing while the airplane was pointed straight down and also when on it’s back (snapping an AT-6 Texan out of inverted flight) and when somewhere around a pitch of 190-200 degrees (pulling just a tad too hard on a Citabria – lousy crummy wing…).

    “If you people want to sound knowledgeable by using aviation terminology you should research the definitions before displaying your ignorance to the world.”

    If you want to sound like you are worthy of being listened too, I’d dial down the snark a bit. When I saw Rand’s comment I knew someone was going to jump all over that. We all know Rand well enough to know he wasn’t minimizing the tragedy to the crew and their loved ones.

    Whoever you are, you are circling the rim of the *plonk* file.

  9. I’ll just toss out an idle thought that would apply IF the aircraft had had a whole lot of altitude when this occurred.

    If the load (probably a military vehicle based on other comments from people at the base) shifted rearward during the steep climb out, then after the inevitable deep stall, when the nose dropped, the load might shift forward again, especially if instead of maintaining thrust during the recovery, the crew deployed full flaps to aid in decelerating the aircraft (to maximize the “slide forward” forces). Then by avoiding another surge of thrust they might have been able to maintain stability while people went rearward to re-secure the load. Unfortunately a take-off just doesn’t leave room for this option, however unlikely it might be to pull off in practice.

    In any event, I’m sure this video will have to be watched by every load master from now until the end of time.

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