Taming the Twin: Single-Engine Operations

[@MarcPagan]

From a MEI - thank you. World class presentation.

[@HendoA35]

Absolutely amazing presentation, only thing that is a bit wrong is at 10:11 you mention the criteria for calculating VMC is lowest weight (which does increase VMC) but according to the FAA Flying Light Twins Safely documentation, it’s max gross weight or any other weight specified by the POH to calculate VMC. Part 23 doesn’t have a regulation corresponding to this anymore (CFR 23.2135 doesn’t mention specific weight) and Part 25 also specifies max gross weight. The reason for this criteria is certification of VMC is the able to have a constant number during test as the lightest weight in any light twin may differ widely even between aircraft of the same type. I bring this up because it was a question I didn’t get right during my CMEL check-ride and this was the correct answer I found after the fact. Hope this helps with your check-ride and good luck to future ME pilots!

[@AirSafetyInstitute]

You make some valid points here and there is not a one-size-fits all answer. While the "Flying Light Twins Safely" document does state that the current Part 23 determination of VMC should be done at maximum weight, that was not the case for the certification of most light twins flying today. The prior version of Part 23 stipulated, "…VMC must be determined with the most unfavorable weight and center of gravity position and with the airplane airborne and the ground effect negligible…” (§23.149(b)). Unlike the other regulations mentioned, they did not stipulate a maximum gross weight. Wind tunnel and other experimentation have shown that a lighter weight is more unfavorable, thus the indication in this video. Going back even further, the original CAR §3.111, which many old twins were certified under, only mentions a rearmost CG. It does not mention the weight at all. The Airplane Flying Handbook sums this up pretty well, "VMC increases as the center-of-gravity (CG) is moved aft. The moment arm of the rudder is reduced, and therefore its effectivity is reduced, as the CG is moved aft. For a typical light twin, the aft-most CG limit is the most unfavorable CG position. Historically, 14 CFR part 23 calls for VMC to be determined at the most unfavorable weight. For twins certificated under CAR 3 or early 14 CFR part 23, the weight at which VMC was determined was not specified. VMC increases as weight is reduced." From a practical standpoint, the most important thing for multiengine pilots to remember is that a higher weight reduces VMC. But this comes with a tradeoff, especially for twins with smaller engines, which might not be able to maintain altitude or climb with one engine inoperative.

[@HendoA35]

@@AirSafetyInstitute thank you so much for the reply and clarification! I love being able to work together as a community and learn together. I only brought it up because I was taught by the 23.149 rule and was told by the DPE that’s no longer the case and to look up to current answer and this is what I found. I wish the FAA would make it clearer rather than have one of their documents say one thing while another specifies the exact opposite, reminds me of the FAA Off Field Landing publication vs 91.119.

[@twentyrothmans7308]

This was very professional. Thank you.

[@mauricioamado5975]

That Piper Aztec is a jewell, by the way stunning presentation, very useful. Thank you👍

[@johnfitzpatrick2469]

G,day from Sydney Australia. Great learning experience. Takeaways for me: the C of G point and effect on rudder control and the plane yaw. ✝️🇦🇺

[@jonasbaine3538]

Thank you.

[@johningram9081]

Very nice video. Thx

[@DumbledoreMcCracken]

If i had money, I could spend 100s of hours playing with with one engine. So much interesting work that could be done.

[@roderickcampbell2105]

An instinctive feel of physics helps. But a better pilot is, well, better.

[@mauricioamado5975]

Hi people, how are you?. Is it a good practise if before take-off I get lined up on the RWY, tap the brakes, apply full power, verify if both engines are giving symmetric power and then start the take-off roll?k

[@danieljones8587]

gracias a mamá por cocinar y a yaw por los gritos! 😮

[@jamesmorris913]

Just buy a Skymaster.

[@singleproppilot]

Control and performance. Got it. So why are most twins so difficult to control and suffer such terrible performance in engine out scenarios? I know the physical, scientific reasons. I’m more concerned with how so many twins achieved certification when they are, in practice, barely flyable with one engine inop. I consider this a significant failure of the aircraft certification process, and I don’t think many twins would pass certification these days. I wish there had been more exploration of centerline thrust designs and other technologies to alleviate these problems.

[@mikearakelian6368]

Poor pl a Ning and exceeding a/c performance capability

[@mikearakelian6368]

You have to do your homework first! Wt/balance told card...have a plan for t/off if you loose one....