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Density Altitude - My Stupid Complacency
No, i didnt wreck my plane, but i could have.
The comparatively wide range of the CG on my 601 XLB allows for carrying, at least, up to max. gross weight and higher.
I have been doing a lot of flying out of relatively high density altitudes - say 5k to 7k DA. I've gotten used to leaning the mixture on all of these takeoffs for max. power - well, sort of.
So, I was feeling quite comfortable departing on a long trip to another state. In all cases I would be dealing with high DA.
After weighing ALMOST everything at home, I took the scale to the airport. I pulled every single thing that wasn't bolted down out of the airplane. I then weighed ALMOST everything before it went back into the plane, including the things I had already weighed at home.
I discarded anything that wasn't necessary for the trip. According to my calcs I was right at max. gross for takeoff.
The one thing i didnt weigh was - can you guess???
My significant other...
I did not want to embarrass her by asking her to get on the scale. Instead I just took her "opinion" on her weight, which she had not confirmed in a long time.
This, stupid decision, combined with a two more errors on my part, almost got us both killed.
The second, which i have yet to resolve, is the inability to do a full power run-up on the ground due to lack of braking power.
My only solution is to do a runup at about 1800 RPM and lean the mixture there.
I should mention that I do have a parking brake system, but even with that engaged and my feet pushing the pedals thru the floor, it will not keep the aircraft from moving forward above about 1900 rpm. So, I can't lean precisely for max. takeoff power. Most of the time I get it close enough. This time I did not.
The last mistake was not considering the use of a higher rotation speed due to the high DA and max. weight.
Oh wait! There was one last mistake I made...
And, yes, the evidence suggests I am truly stupid! 30 years of flying has apparently made me complacent, or old age has just deteriorated my brain to dangerous levels.
Rolling down the runway I knew i was below max. rpm. It was just about 2200 instead of the 2350 I was looking for. I have aborted takeoffs at this rpm before. I didn't this time. I may have been thinking "we're heavy, so rpm should be a little lower (wrong)".
When i reached normal rotation speed, i gently pulled back on the yoke. I had already told wifey we would be leveling off immediately after rotation to pick up speed before continuing our climb. Well, that did happen, but not by choice
I gently pulled the nose off and the wheels broke ground - and then we dropped right back down on the runway!
For reasons I will never be able to explain, I continued the takeoff. I got her up to 60 mph and rotated and she started climbing - at about 50 fpm!
Stupid, stupid, stupid!
This was the second scariest take off of my life (the first I can put down to inexperience).
I did not think we were going to clear the trees at the end of the runway.
I scared the crap out of myself and my wife. It marred the rest of the flight to our anniversary vacation resort (Sunriver, Oregon).
So I make this confession, mostly to hammer into my feeble brain, to never put myself and the love of my life in this situation again.
A few take-aways:
- do more flight testing for high DA take-offs.
- fix the braking system to allow for full run-ups
- be more conservative on load weights
- If close to max weight - never, ever, trust someones estimate on their weight.
- abort the damn takeoff if its not right!!!!
- don't be stupid.
- no really, dont be stupid!
Replies to This Discussion
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Permalink Reply by David Krakowsky on
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Thanks for sharing your experience
I am also flying for about 30 years and have made
some blunders myself that I wouldn’t share.
as far as your brakes not holding, I don’t think
there are too many 601’s that will hold still under a
full power run up.
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Permalink Reply by John Austin on
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Gary,
Thanks for taking a bad experience, analyzing it, and teaching us. All of us need a "reality check" occasionally. Zenith's are great airplanes with benign flight characteristics, but, as Max Stanley once said about the Cub, "The Piper Cub is the safest airplane in the world; it can just barely kill you."
John
N750A
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Permalink Reply by Paul Sanders on
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Thanks for sharing, it is good to be reminded of these things, especially for low landers like me (at -115ft).
I dont know about the brakes on the 601 but for the ones that come with the 750, Matco sells an upgrade that intensifies the braking power quite significantly. If you have the same brakes, that might be something worth doing. I have the same problem as you - I can’t do a full power runup with my rotax and stay where I am. I plan to upgrade at some point but want to enjoy my new plane for a bit before I start taking her apart.
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Permalink Reply by Don Morrisey on
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Excellent flight report. What’s great about your report is there is no EGO involved, just the facts. We should all be so honest and self critical. Well done.
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Permalink Reply by Gary Welch on
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Honestly, this experience has got me questioning everything about my suitability as a pilot. I study some part of aviation every day of my life. I read a host of aviation forums and articles every single day - and have for many years. I have learned a lot about flying.
I have also been motivated by the fact that over a period of a year and a half, while taking my private pilot training, seven people I knew died in five separate accidents. I learned early that unless I do everything right, every time, I'm likely going to kill myself. True or not, that's the mindset I got after having so many people I knew die in such a short period of time.
And 30 years later, and a bunch more learning, I go and create a near perfect accident chain. And I do it with my wife in the plane. I just cannot let this go and don't know how to resolve it in myself. I keep going over and over it in my mind and I just can't understand how I made so many mistakes and continued to blunder on.
It has really got me wondering whether I can trust myself to be a pilot? I'm leaning towards, "no".
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Gary
its normal to question our abilities after a screwup. Don’t be so hard on your self. Use it as a lesson
to learn from.
If you are seriously concerned get a couple of hours with a good cfi to sharpen your skills.
fly religiously with a checklist.
We have all been there in your shoes.
Don't give up!
Dave
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I have been considering the Matco brake upgrade for a while. My only reservation is my brakes are so hard to access, even with my removable top skin.
Trying to reach down and work on them is my worst nightmare as I have a bad back and the pain is extreme in this position. The only people I know who could help me are also older and it would be just as difficult for them. In addition, there is so much wiring and cables in the way it seems near impossible without pulling half the panel apart.
I have to pull the top skin to do some other upgrades shortly and I'll take a closer look at what's involved then. Maybe it won't be so bad...
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Permalink Reply by Charles Clayton on
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About the brake issue, my 601 XLB was built in the Czech republic. It had Marc Ingegno brakes and holding it still for runup was always an issue. Being I was using the plane for training, by the time I had 300+ takeoffs/landings I had to "cheat" a bit on my runup(supposed to be 4000 RPM) so it would stay still. I had my mechanic look at the brakes and we decided to get new ones. Zenith was selling the Matcos and because my landing gear is a bit different that what they currently make, he had to make some parts but was able to install them. Since then I have no problem holding the plane still.
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Permalink Reply by Jim and Amelia Isaacs on
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Gary,
Thanks for sharing. Yes a bit of self reflection is natural but I agree with David, don’t be too hard on yourself. Perhaps one thing you could consider is to change your type of flying. That’s what I’ve done. For me, I’ve decided to stop using a small single engine plane as a means of transportation, rather, it’s now purely for recreation and education. I don’t plan to install a transponder. For me, the days of flying myself and my family to airports requiring one are over. It’s an acknowledgement I’m growing older and at the same time, removes the pressures and stress associated with telling family or friends you will be there via your airplane. It eliminates the temptation to convince one’s self one should attempt to launch because it’s too late now to drive to your destination, the need to pack a few extra things for the trip, etc. For me, it removed the worry of the constant checking of the weather after we arrived to make sure we can get back home on time to avoid the cost of an extra night in a hotel, or missing an important meeting at work on Monday. An old FBO owner and pilot once told me you can use almost any airplane to travel but if you need to keep a schedule it better be a half-million dollar airplane. I will use my 701 just to enjoy flying on pretty days and expose as many people I can to flying, and everyone approaching a purely recreational event understands these events are completely optional. Just some food for thought. Hand in there!
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Jim;
Thank you for the well reasoned response. I think part of my problem was allowing the pressure of our reservations, and not wanting to disappoint my wife, that contributed to my poor ADM. No excuse, but I think it was a part of it.
Oh, but how many articles have I read on get-there-itis??? Dozens. Why didn't I recognize this was happening at the time??? This is what bothers me....
That and just not having the correct mind set that's required for every take-off.
All of the issues you mentioned were on my mind at various points in our trip. I also had the added anxiety of dealing with changing smoke conditions from multiple fires along our route.
I think your best advice, that I will take to heart, is to not plan this type of trip again (one where we have fixed, extended, reservations).
Thank you for your perspective on this and taking the time to help me. I really appreciate it!
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Permalink Reply by John Schaper on
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Glad you're here to talk about it. Experience is a hard teacher. The test comes first, then the lesson.
Haven't flown the Zenith yet (still building) but unless it's a short runway you always have the abort option, unless your past V1.
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I absolutely should have aborted this take-off. Why I didn't, I just don't know.
I know I need to be hard-wired to abort every take-off, and I usually am. This time I wasn't and it was a scary lesson.
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