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Thread: Cross Checking

  1. #1
    Member Dojo's Avatar
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    Cross Checking

    A phrase I've probably used more in the last two weeks than in my entire life, "cross check". I'm curious to know amongst the aviation pros here, about methodology.

    I feel... inefficient. For example, in an ILS approach, I'm heads down, checking HSI, ADI, Airspeed, VVI. I don't do this in a particular order, but there's some logic to it. e.g. if I noticed my pitch down on the ADI, I'll glance at my airspeed. Perhaps I should be more systematic?

    What do real pilots do? Is there a taught method of cross checking? Time to examine per instrument? Order of check? etc?

    Moreover, I think it'd be great to have a cross check reference sheet, for many of the critical tasks.

    Off the top of my head, as examples:

    1. ILS - (instruments checked per point in the approach, plus method)
    2. Surface attacks: (Cockpit references, airspeed, baro alt, etc)
    3. Tactical formation (how frequently to visually sweep wing, airspeed, etc)

    I suspect that if we're each more methodical, even prescriptive, we'd be tighter.

    Thoughts? Am I off here?

  2. #2
    476 vFG Founder Snoopy's Avatar
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    First I'd say don't over complicate it. Second here is what is in our upcoming TTP

    2.13.1.2 Instrument Cross-Check.
    Instrument cross-checking is the division of attention equally between control and performance instruments. In general, the crosscheck will progress from the ADI, out to another instrument, back to the ADI and then out again. Do not fixate on a single instrument, this could lead to a potentially fatal situation. Be aware of performance instrument lag due to mechanical characteristics of some instruments and the inertial properties of flight. Be mindful of the inherent lag between control input and the appearance of the effects of that input. Make small inputs and allow the performance instruments to catch up prior to making additional inputs.

  3. #3
    Retired Pilot Tex's Avatar
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    From the 11-217 I was referencing a few days ago Dojo:

    1.2.4. Cross-Check Technique (Figure 1.2).
    1.2.4.1. Crosschecking is the efficient division of attention between control and performance instruments, the ability to interpret the information given by those instruments, and the correction of any discrepancies noted in aircraft flight parameters. The act of crosschecking is often compared to the hub and spokes of a wagon wheel where the ADI is the hub and the other instruments are the spokes. In general, the crosscheck will progress from the ADI, out to another instrument, back to the ADI and then out again.
    1.2.4.2. Performance Instrument Lag. Due to mechanical characteristics of some instruments and the inertial properties of flight, there is an inherent lag between a control input and the appearance of the effects of that input on the performance instruments. A common mistake is to watch the performance instruments while making control inputs, resulting in overshoot of desired flight parameters. Experienced pilots learn to make small calculated inputs and allow the performance instruments to catch up before making another input.
    1.2.4.3. Fixating on a single instrument is a common and dangerous error made by inexperienced pilots. If one flight parameter, (e.g. altitude) is frequently wandering, the pilot will devote too much time to the altimeter and lose track of other critical parameters (e.g. attitude). The pilot must remember that the attitude of the aircraft, not the altimeter, is what is causing the aircraft to be off altitude. Returning to the basic crosscheck flow will solve the problem and prevent the aircraft from entering a dangerous attitude.

    Cross check.JPG

    Bottom line: You want to keep scanning and not stare at one thing for more than a second or two. The number of safety reports I've seen where a pilot or crew gets focused on one minor thing is staggering but having been there, its easy to get channelized.
    Last edited by Tex; 02Jul15 at 17:28.
    “Rules are made for people who aren't willing to make up their own. " - Chuck Yeager

  4. The Following 2 Users Say Thank You to Tex For This Useful Post:

    Dojo (02Jul15), Kimi (02Jul15)

  5. #4

    TWOT


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    Oliver's Avatar
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    I recall from flight school that there are different cross-check procedures for different scenarios. For example in a straight and level flight you do not take the VVI into the cross-check at all but in a dive/climb you do, thereby sacrificing the priority of other instruments. Another one is that when youre not in a bank/turn you dont go back to the ADI immediately after taking note of another instrument.

    I will have to dig up some old readers to be more specific. In the meantime if anybody knows what Im talking about and has the proper procedures for every situation, please share them.


    A mission’s execution often reflects the quality, discipline, and tone set in the briefing. - Chris “Kimos” Haave

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