V1 Speeds for 172’s and other small GA Aircraft and RTO’s

7 Answers

1. 
   

   
   

   Kris Kortokrax on Apr 17, 2014

   There is no V1 for a Cessna 172 because it is not a certification issue for a single engine airplane. See 14 CFR 23.51 (it can be found on http://www.faa.gov under Regulations) for a description of Takeoff Speed certification requirements.

   The Takeoff and Climb task in the Private Pilot PTS requires a familiarity with rejected takeoffs.

   You would be much more likely to notice a low tire while taxiing than to experience a blowout on a takeoff roll. The takeoff roll for a 172 is so short, you would probably be off the runway and not notice the flat tire if you didn’t notice it while taxiing.

   Probably a more likely scenario for a rejected takeoff would be if you were departing from a crossing runway and noticed someone taking off or landing on the other runway.

   Of course, we practice rejected takeoffs, as well as rejected landings (go-arounds).

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   Wes Beard on Apr 17, 2014

   All here are certified under Part 25 Transport category aircraft while all small GA airplanes are certified under Part 23. V1, VR and V2 are not required to be calculated for Part 23 aircraft.

   The best idea for you is to take the liftoff speed as your decision to abort if anything happens.

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3. 
   

   
   

   Kris Kortokrax on Apr 17, 2014

   V1 is required to be calculated for multi-engine jets per 23.51(c). The Cessna Citation Mustang (CE-510) comes to mind as a Part 23 aircraft for which V1 must be determined.

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4. 
   

   
   

   Brian on Apr 17, 2014

   If I get a flat in a 172 at any point in the THREE WHEEL t/o roll I’m stopping, not flying. I operate out of a 2000 foot strip with a lake at both ends. I’ll swim at 10 knots vs fail to lift off at 45 knots any day of the week. At any other runway (typically closer to 3k or better) you’ll stop anyway. In other words, this concern is not relevant in a small trainer. Even in a Bonanza, Mooney, Columbia or any other higher performance single. If you get a flat stop.

   I finish this with concluding that you always perform a takeoff where the aircraft lifts off when it wants to, not at some rotate speed specified in the POH. What I mean is, after application of full power and a quick check of the instruments (seconds), you pitch to a Vy climb (roughly 1-2″ wheelie) and ride that till lift off. This requires a constant relaxation of control input during the rollout process.

   Note: this technique takes a great deal of weight off the wheels very early, which means, as Chris points out, chances are good you won’t even notice a flat that you wouldn’t have noticed already during the taxi/runup process.

   Just my 02 though, take it as such.

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5. 
   

   
   

   Sam Dawson on Apr 18, 2014

   As pointed out there is no real V1 in part 23/CAR 3 airplanes. Now you can figure an accelerate/stop distance, or at least approximate one. Take your takeoff ground roll and add this number to your landing ground roll. Maybe multiply by 1.2-1.5 for the “oh crap” factor. This is the distance you need to accelerate to rotation speed and, assuming a catastrophic failure at that point, stop the airplane.

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6. 
   

   
   

   Kris Kortokrax on Apr 18, 2014

   I don’t make this stuff up. There is a real V1 in Part 23.

   § 23.51 Takeoff speeds.
   (c) For normal, utility, and acrobatic category multiengine jets of more than 6,000 pounds maximum weight and commuter category airplanes, the following apply:

   (1) V1 must be established in relation to VEF as follows:
   (i) VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant but must not be less than 1.05 VMC determined under § 23.149(b) or, at the option of the applicant, not less than VMCG determined under § 23.149(f).
   (ii) The takeoff decision speed, V1, is the calibrated airspeed on the ground at which, as a result of engine failure or other reasons, the pilot is assumed to have made a decision to continue or discontinue the takeoff. The takeoff decision speed, V1, must be selected by the applicant but must not be less than VEF plus the speed gained with the critical engine inoperative during the time interval between the instant at which the critical engine is failed and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot’s application of the first retarding means during the accelerate-stop determination of § 23.55.

   (2) The rotation speed, VR, in terms of calibrated airspeed, must be selected by the applicant and must not be less than the greatest of the following:
   (i) V1;
   (ii) 1.05 VMC determined under § 23.149(b);
   (iii) 1.10 VS1; or
   (iv) The speed that allows attaining the initial climb-out speed, V2, before reaching a height of 35 feet above the takeoff surface in accordance with § 23.57(c)(2).

   (3) For any given set of conditions, such as weight, altitude, temperature, and configuration, a single value of VR must be used to show compliance with both the one engine inoperative takeoff and all engines operating takeoff requirements.

   (4) The takeoff safety speed, V2, in terms of calibrated airspeed, must be selected by the applicant so as to allow the gradient of climb required in § 23.67 (c)(1) and (c)(2) but must not be less than 1.10 VMC or less than 1.20 VS1.

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   Sam Dawson on Apr 19, 2014

   Sorry- Kris is correct. I should have clarified my statement that I was referring to SEL airplanes which is what the OP asked about.

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