Critical Understanding #1, Take off distance.


Walk up to a pilot who just flew a plane, and ask them a simple question: “What is the pilots operating handbook (POH) take off distance for your plane?”  and 75% of them will not be able to answer you with a real number. Yet this is a critical fact for the Pilot in Command (PIC) to know.


Would you like to read a story about a guy killing himself and his wife by ignoring the published take off distance for his plane? I wrote one several years ago about a 2007 accident, you can read it here: Couldn’t have happened to a nicer guy…… Notice that the PIC rolled 2,500′ into a 10 mph before his plane lifted off, that is five or eight times as long as it should have taken to get airborne. He had 60 seconds to pull the throttle back and roll to a halt, but didn’t. Even at the 2,500′ mark he could have aborted, and easily stopped on the remaining 1,500′ of runway, but he didn’t. Instead he chose to die and kill his wife also.


Current Zenith Aircraft literature clearly states a 650 with a 110 hp engine at gross weight has a take off roll of just 500′ There are published numbers for every model of their planes, but 600′ is representative of most of the 600 series Zeniths with 100 hp. As an additional free resource to our builders, I operate our private Zenith/Corvair Database and discussion group, where more than 100 builders can directly share this information. Read: “Zen-vair” and “Piet-vair” Discussion Groups, your resource. Thus any builder has acess to know just how long it should take his plane to get off the ground before he ever flies it.


Since I published the crash story years ago, We have had the discussion groups for years, and Zenith has always had performance numbers available, the easy conclusion is that no one should have been hurt in an accident like the one detailed above, right? Guess again: In the last 3 years, we have had four other pilots destroy their planes in nearly identical accidents just like the one above.  These accidents were directly the pilot in Command’s fault, period. If a plane is supposed to take off in 600′ and the pilot is still holding the throttle in when the plane passes the 1,000′ mark on the runway, than every single thing that happens after that, injuries and damage, is absolutely and solely his fault, no matter what he and his attorneys want to claim. In the case of the 2007 accident, the only redeeming thing Ray Blondin did was make sure there were two less scum lawyers in the world, and I gladly praise him for it.


Since 2009, we have had a “Flight Operations Manual”, that includes a proven format for running a Zenith specific flight test program, and a number of articles specifically about flight test protocols. Half the articles in the Manual were written by Zenith pilots. I wrote a list of ten things never to do on a first flight, and one of the pilots who ignored standard take off distance and destroyed his plane less than 60 seconds into his first flight, broke four of the rules, and he brought a passenger, fueled his plane with gas 9 points below the required octane, and wait for it: Ignored an email from me the day before the flight telling him his plane was not airworthy. If you think I am kidding about this, just read this: Understanding Flying Corvairs Pt. #6, 98% DNA not enough.


 If that story isn’t bad enough, I have another where a Zenith pilot with his prop pitch set wrong turned his engine 3,800 rpm Static. He did his first flight from a pave 5,000′ runway, and later said that his plane took 4,000′ to break ground, and had less than 50′ altitude at the end of the runway. This was his first flight, he flew “cross country” that way for a few minutes until he hit a small tree. Because God has a sense of humor I am yet to understand, he lived.


Here is the bottom line rule: No matter what kind of plane it is, no rational PIC sitting in the cockpit about to take off, pushes the throttle forward without knowing the exact distance it will take to get his plane airborne, and all rational pilots decide before they start moving, they will abort the take off the second the plane goes past the take off point and is still on the ground. There are no exceptions here, there is no excuse for rolling down the runway and hoping the plane gets off the ground.


Before getting in the plane, the pilot must know:

The POH take off roll for his plane on a standard day.

(Make this line 1.1 in your Hand book)

The adjustment made to this number for his available HP output.

(Make this line 1.2 in your Hand book)

The adjustments made for the atmospheric  conditions that differ from standard

(Make this line 1.3 in your Hand book)

And he must have a physical distance marker (like counting the number of runway lights that make up the distance, at our airport they are 200′ apart, and if a Zenith isn’t airborne by the third, the take off would be aborted.)


If your own personal POH for your plane doesn’t have the first three written down in it before the first flight, your not just taking a stupid chance without a plan, your plane is not airworthy in my book, period.


If that sounds like too much to for a guy to know, he is with the majority of pilots flying, who just guess at these things, but if you want to know what you are doing around planes, you will be able to answer anyone who asks these questions. The alternative is just being part of the herd that just pushes the throttle forward and hopes things turn out for the best. Take your pick.





5 Replies to “Critical Understanding #1, Take off distance.”

  1. Mike, I have plenty of evidence that too many people are not listening, in the form of pointless accidents and foolish operations. I have put out 25 years of effort into education, mostly said very nicely. The evidence is
    that it didn’t work well enough. Call me any name you like, tell me I’m doing it wrong, anything you like, just read and follow the information, or don’t but I don’t feel obligated to try being even nicer out of fear of loosing thin skinned people wo are not listening. -ww.

  2. All Corvair powered aircraft pilots and “wan-a-bees” should thank GOD that they have a Professor / instructror/ Trainer like you

    1. Bob, I appreciate the thought, but think that is overstating it a lot. All I want people to do is use the information I have learned at great cost. Just taking the task seriously and being willing to learn is the only thanks I need. I saw the international news this morning, God has plenty of other things to attend to. -ww.

  3. Military runways have always had markings of runway remaining in 1000′ increments to aid in takeoff and landing abort decisions. Those markings have been added to air carrier runways as well if I am correct as well as runway lights showing amber at that point. Maybe it would be best if those runway remaining signs were universally available, seeing that 1000′ marker could be just the kick in the pants some of those pilots needed to accept that their takeoff attempt was not going to work. Maybe even that would not stop them but it is worth considering.

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