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Thread: Full run-up?

  1. #21
    Mayhemxpc's Avatar
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    When I am giving a flight review or a check-ride (CAP) I always ask if the pilot calculated take-off distance for today. Sometimes they did, more often I get a response like, "We have 6000 feet of runway, surely that is enough." My response -- and my reason for asking -- is, if you know that on that particular day at that particular loading, that the airplane should reach Vr at 800 feet and you pass the aim point markers or VASI lights but you are not yet seeing Vr, it is probably time to abort the takeoff -- while you still have 4 or 5 thousand feet to stop safely. (Shorter runways have different considerations, but the basic idea remains the same -- do you have enough to take off? To stop? When do you make the decision and what will happen next?) Multi-engine thinking for single engine pilots.

    Question for flight reviews: What would cause you to abort the takeoff?
    Chris Mayer
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  2. #22

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    Quote Originally Posted by Mayhemxpc View Post
    When I am giving a flight review or a check-ride (CAP) I always ask if the pilot calculated take-off distance for today. Sometimes they did, more often I get a response like, "We have 6000 feet of runway, surely that is enough." My response -- and my reason for asking -- is, if you know that on that particular day at that particular loading, that the airplane should reach Vr at 800 feet and you pass the aim point markers or VASI lights but you are not yet seeing Vr, it is probably time to abort the takeoff -- while you still have 4 or 5 thousand feet to stop safely. (Shorter runways have different considerations, but the basic idea remains the same -- do you have enough to take off? To stop? When do you make the decision and what will happen next?) Multi-engine thinking for single engine pilots.

    Question for flight reviews: What would cause you to abort the takeoff?
    Chris,

    Good points but one familiar with their aircraft really doesn't need a take off calculation it parameters are predictable, with a good margin. Example would be a 172 with 2 people, half fuel, standard temp, no gusts, ice or issues, on a 3500 ft strip, there's just no need to do a takeoff calc. You know it will work.

    Now it it's 1200 feet, worth examining it much more critically. So, it depends.

  3. #23
    Mayhemxpc's Avatar
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    Maybe I am misreading your post, but I think that you might miss the point. Of course it should be an easy guess that 3500 feet should be enough for a C172 at MGW with reasonable density altitude. That wasn't the point. The issue is being able to stop the airplane safely before you run out of runway if something isn't right. I agree that a pilot familiar with his or her aircraft should know the point at which an abort decision would have to be made without having to figure it out each time. I know without calculating that half loaded, my plane should be at Vr NLT 1000 feet down the runway. Not that I have some inherent insight, it is that I have done the calculation enough that I know the rough parameters by heart. I am constantly surprised at how many pilots don't know the abort point. What is the abort point on your 172? If someone is really familiar with the plane, they don't have to think about in feet, but in time. If not at Vr about 20 seconds after feeding the front engine in, something is wrong. Stop and figure it out.

    So I ask pilots to figure that out for me on any review or instruction I give. If the pilot can give me a ball park answer that is fine. After all, we are not going to fly in test pilot conditions.
    Chris Mayer
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    www.o2cricket.com

  4. #24

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    Quote Originally Posted by Mayhemxpc View Post
    Maybe I am misreading your post, but I think that you might miss the point. Of course it should be an easy guess that 3500 feet should be enough for a C172 at MGW with reasonable density altitude. That wasn't the point. The issue is being able to stop the airplane safely before you run out of runway if something isn't right. I agree that a pilot familiar with his or her aircraft should know the point at which an abort decision would have to be made without having to figure it out each time. I know without calculating that half loaded, my plane should be at Vr NLT 1000 feet down the runway. Not that I have some inherent insight, it is that I have done the calculation enough that I know the rough parameters by heart. I am constantly surprised at how many pilots don't know the abort point. What is the abort point on your 172? If someone is really familiar with the plane, they don't have to think about in feet, but in time. If not at Vr about 20 seconds after feeding the front engine in, something is wrong. Stop and figure it out.

    So I ask pilots to figure that out for me on any review or instruction I give. If the pilot can give me a ball park answer that is fine. After all, we are not going to fly in test pilot conditions.

    Chris,

    Good points. One does need to have an abort point/plan in mind before taking the runway and questioning that for a review tells you if he's got that plan done.

    Also, we have to accept that we "may or may not" have enough runway to stop short of the end, or continue to fly. A good deal of the time, in twins, we have an area where you just can't do either.... and if you abort, you're going off the end. That's a risk benefit we need to examine on every flight. Fortunately, in most of todays GA twins we can have a "balanced field" with about 5000 feet. I know a lot of POHs say you can do it in less, but I'd be doubtful for most of us.

  5. #25

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    Quote Originally Posted by Bob Dingley View Post
    Lets parse the question. "Run up" is kind of vague. Lets ask "Do you run the full checklist or the alternate checklist?" Example: the kid brother of a friend made an intermediate stop 30 miles short of destination in a Barron to drop off one passenger. He was in a big hurry and no checklist. He made a fast turn onto the active while pushing the throttles open. Intersection T.O. Rotated early due to less than full runway. It was then that he realized he was still on AUX tanks (they were pretty low). Number one quit while rotating. And everyone here knows why. Whats amazing is everyone lived. Barron destroyed.
    Bob,

    I hate to hear this. Thanks God everyone lived (except for the Baron). the kid brother made TWO crucial mistakes. He failed to properly do the landing checklist on the previous flight.... and failed to do the before takeoff checklist on the crash flight. For a professional pilot, it's inexcusable.

  6. #26

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    Quote Originally Posted by Jim Hann View Post
    Thanks, I only had two single engine landings in those years and no single engine takeoffs. Both shutdowns were control cable failures (one each throttle and mixture) not engine problems. I loved both airplanes but I don't miss making a living in recips!

    Jim
    Jim,

    Perhaps I'm missing something, but why would you shut down with a control cable failure? I've had a few of them, but never had to shut down.

  7. #27
    Mayhemxpc's Avatar
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    It occurred to me that I never answered the original question.

    If if I shut down the engine for however long I do a run up. Lots of funny things can happen during start up. It only takes a few seconds and it makes me feel better. That is not to say I have never stopped an engine, restarted an took off without a new run up. There are certain circumstances where I will skip it.

    If I don't shut down the engine -- like land, taxi back and take off again? No, I don't do a new run up. I am sure that someone will be able to explain to me why I should. If so, I will listen attentively.
    Chris Mayer
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    www.o2cricket.com

  8. #28
    Jim Hann's Avatar
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    Quote Originally Posted by Lrrryo View Post
    Jim,

    Perhaps I'm missing something, but why would you shut down with a control cable failure? I've had a few of them, but never had to shut down.
    I had two failures, both on a Beech Baron 58 (light twin).

    The first one was a mixture control, apparently it goes to idle cut-off when the cable breaks on the Baron. All I know is the fuel flow gradually decreased until the engine was just windmilling. No power left from it, we feathered it so that we would keep on flying. We (I had another pilot with) were mid-weight but the Baron is a good single engine airplane and we were able to continue on to our destination.

    The second was a throttle cable. This time I was very light (me, full tanks minus the 1:20 flight, and 5lbs of paper). I found out the cable was broken when it came time to descend. Once I realized what happened I had to reduce power somehow... Since I knew I could maintain altitude and shoot an ILS (it was IFR of course) on one engine at my weight I just pulled the mixture on the uncontrollable engine.

    The other thing, it was the right engine both times, not the left.
    Jim Hann
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    1957 Piper PA-22/20 "Super Pacer"
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  9. #29

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    Quote Originally Posted by Jim Hann View Post
    The first one was a mixture control, apparently it goes to idle cut-off when the cable breaks on the Baron. All I know is the fuel flow gradually decreased until the engine was just windmilling.
    I had a mixture cable break on a Baron. It remained at the last set position, cruise at 10k feet. When I descended, the mixture was too lean and I had to keep reducing power because the engine was threatening to quit. So I got this idea to put the boost pump on high. It kept the engine running all the way to touchdown.

  10. #30
    Jim Hann's Avatar
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    Quote Originally Posted by martymayes View Post
    I had a mixture cable break on a Baron. It remained at the last set position, cruise at 10k feet. When I descended, the mixture was too lean and I had to keep reducing power because the engine was threatening to quit. So I got this idea to put the boost pump on high. It kept the engine running all the way to touchdown.
    We were 75% power, leaned, at 4,500' MSL VFR. The indicated fuel flow gradually went to the bottom of the scale, I can't remember exactly what that was, its been 21 years. The airplane started to yaw as the power fell off. We hit low then high fuel pump and got one or two surges and she was done. It was a BE58, N95BB, s/n TH-333 back in 1995, looks like it is still flying with a different company.

    All I know is what happened that time, never had another failure like that. Heck, maybe it was a fuel servo failure, maintenance and the FAA never said boo about it but I'm guessing that the company didn't report anything other than what it had to (or the FAA found out about through other channels). I do know we didn't run out of fuel! (Yep, we checked after we landed!)

    Being a recip I don't think they had to report the inflight stoppage under NTSB 830, even though it was a 135 operation.
    Jim Hann
    EAA 276294 Lifetime
    Vintage 722607
    1957 Piper PA-22/20 "Super Pacer"
    Chapter 32 member www.eaa32.org
    www.mykitlog.com/LinerDrivr
    Fly Baby/Hevle Classic Tandem


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