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5 Answers

SID minimum climbing rates

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FAA Regulations

Do the minimum climbing gradients specified in the SIDs assume  that in an twin engine airplane both engines are  working?  It would appear that many light twins cannot even meet the minimum climbing rate of 200 ft/NM with one engine inoperative.  Where is this covered in the FAA rules? With respect to this specific issue are the rules different for turboprops and jets?

Thanks

 

 

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5 Answers



  1. John D Collins on Apr 30, 2017

    The standard climb gradient is 200 feet/NM. It does not change for multi-engine. If the pilot can’t maintain the 200 feet/NM gradient or any other specific climb requirement, they should consider developing a plan to deal with the situation. I believe that air carriers are required to do so. There often may not be a viable solution, just like a single engine airplane that loses its engine.

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  2. Wes Beard on Apr 30, 2017

    AIM 5-2-8

    2. ODPs and SIDs assume normal aircraft performance, and that all engines are operating. Development of contingency procedures, required to cover the case of an engine failure or other emergency in flight that may occur after liftoff, is the responsibility of the operator. (More detailed information on this subject is available in Advisory Circular AC 120−91, Airport Obstacle Analysis, and in the “Departure Procedures” section of chapter 2 in the Instrument Procedures Handbook, FAA−H−8261−1.)

    The rules are the same for all aircraft. You must develop contigency procedures. In small light twins that would effectively, for me, mean I take off in VMC conditions in case I lost an engine. Most airlines use runway analysis for their contigency procedure. Lacking a good contigency plan you will need to make the SID or ODP single engine. Something that many aircraft cannot accomplish either due to poor climb performance or lack of performance data in the AFM / POH to justify the takeoff.

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  3. jeff on May 01, 2017

    You have to be able to make the climb gradient with one engine on a ME aircraft if you want to be safe. You also need to make the climb gradient both off the runway and top of ascent. For instance, leaving KASE, there are departures like the LINDZ8 which requires a climb gradient of 435’/nm from take off all the way to 10,000′ ( doing it from memory). Most jets/part 25 aircraft publish what are called net second segment climb gradients expressed as a percent. (435′ per nautical mile is aporox 7.8%) These tables generally assume a faled engine. These table generally assume you are in take off config, one engine (on a two engine plane) and that you maintain V. 2Second segment is used becaused that is the segment you are in until either 400′ agl OR obstacle clearance (10,000′ in this example). If you take off in IFR conditions and loose an engine after V1, you would still have to make that gradient in order to not slam into a culmulo granite.

    Frankly, most Corporate jets and all prop planes that I am aware of would not make the gradient on one engine. So you are taking a big risk if you depart under those conditions. You either have to lighten the plane significantly/take off during a cooler time of day, which increases the gradient the aircraft can make, or wait till VFR conditions so you can steer around obstacles if you lost an engine.

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  4. Charles22 on May 02, 2017

    Thanks to All for your replies

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  5. MarkO on May 06, 2017

    Keep in mind that you also may not be able to “see and avoid” obstacles in visual conditions if you don’t have the performance to do so. Just saying you plan to does not mean you can actually do it. What’s your deck angle at Vyse?

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