REFLECTOR:Follow up on my bad landing
Donald Royer
reflector@tvbf.org
Tue, 6 Apr 2004 12:07:01 -0600
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I promised more information on my bad landing last week as soon as I had more information. After thinking more about what happened and talking to several eye witnesses who between them saw all of the incident, I can say with some confidence exactly what happened.
First , if was not a gear collapse, it was a gear up landing. What initially confused the situation was when the plane can to a stop, the gear was out of the gear wells and resting on the ground. In addition the gear switch was in the down position. However, a pilot who was out walking his dog at the appropriate end of the runway and who saw the final approach and touchdown was quite sure that the gear was in the wells at the time of touchdown. That information along with the information that I reported before that I was distracted enough that I really could not say whether I had two greens or not, but that I would in all probability have seen the red gear unsafe light if it had been on seems to lead to one conclusion.
The only scenario that I could come up with the fits everything is the following. I put the gear switch down at the appropriate time but then nothing happened. This possibility has been discussed here on the Reflector before and in fact I have installed the little circuit to bypass the down pressure switch to get out of this condition. Then, the shock of the landing jarred the system out or the hang up and the gear tried to extend as I was sliding down the runway. This conclusion is also supported by the fact that I heard the gear horn at about ten feet. My simultaneous reaction was to think that the gear warning system was malfunctioning again as it had several times recently, and before I got around to considering that it might be telling me the truth this time, I was on the ground.
I put the cause to be a combination of a known flaw in the system and pilot error. I simply did not notice that the gear had not extended when it should have. In my defense, I was distracted at the time, it was late afternoon and the sun was in my eyes and the air was very bumpy. In addition, I was probably paying too much attention to the head temperatures. The purpose of the flight was to check some changes in the air baffling. I can assure you that never again will I land without being sure that I have two greens regardless of any other circumstances.
It could have been worse, there was remarkably little damage and the FAA didn't get involved. A number of airport people helped me get the plane off of the runway and into my locked hangar as soon as possible. The only damage was the expected scraped belly, a little nonstructural damage to one wing tip, and over course, the prop.
There has been a lot of bad mouthing of MT going on here right now, but my prop got abraded down to about half of it's original diameter without damaging either the engine or the prop hub. That is going to save me much money.
The following is more speculative. I may have uncovered at least one cause of the down pressure switch hang up. We were having one of our down slope wind situations where the air temperature can jump twenty to thirty degrees in an hour or so, and the plane in the hangar was probably at least 30-35 degrees cooler than it was in flight. With that in mind, I tried a little experiment this morning. I went out to the hangar when the temperature was about 35 degrees. With the plane up on jacks, I retracted the gear and left it up while I warmed the hangar as fast as I could with a propane heater making sure that the warm air was circulated through the nose compartment and the cabin of the plane. When the temperature in the hangar reached 80 degrees, I tried to lower the gear "BINGO" it was hung up. This is only one data point and it may not be reproducible, but it worked once for me.
Donald Royer
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<DIV>I promised more information on my bad landing last week as soon as I had more information. After thinking more about what happened and talking to several eye witnesses who between them saw all of the incident, I can say with some confidence exactly what happened.</DIV>
<DIV> </DIV>
<DIV>First , if was not a gear collapse, it was a gear up landing. What initially confused the situation was when the plane can to a stop, the gear was out of the gear wells and resting on the ground. In addition the gear switch was in the down position. However, a pilot who was out walking his dog at the appropriate end of the runway and who saw the final approach and touchdown was quite sure that the gear was in the wells at the time of touchdown. That information along with the information that I reported before that I was distracted enough that I really could not say whether I had two greens or not, but that I would in all probability have seen the red gear unsafe light if it had been on seems to lead to one conclusion.</DIV>
<DIV> </DIV>
<DIV>The only scenario that I could come up with the fits everything is the following. I put the gear switch down at the appropriate time but then nothing happened. This possibility has been discussed here on the Reflector before and in fact I have installed the little circuit to bypass the down pressure switch to get out of this condition. Then, the shock of the landing jarred the system out or the hang up and the gear tried to extend as I was sliding down the runway. This conclusion is also supported by the fact that I heard the gear horn at about ten feet. My simultaneous reaction was to think that the gear warning system was malfunctioning again as it had several times recently, and before I got around to considering that it might be telling me the truth this time, I was on the ground.</DIV>
<DIV> </DIV>
<DIV>I put the cause to be a combination of a known flaw in the system and pilot error. I simply did not notice that the gear had not extended when it should have. In my defense, I was distracted at the time, it was late afternoon and the sun was in my eyes and the air was very bumpy. In addition, I was probably paying too much attention to the head temperatures. The purpose of the flight was to check some changes in the air baffling. I can assure you that never again will I land without being sure that I have two greens regardless of any other circumstances.</DIV>
<DIV> </DIV>
<DIV>It could have been worse, there was remarkably little damage and the FAA didn't get involved. A number of airport people helped me get the plane off of the runway and into my locked hangar as soon as possible. The only damage was the expected scraped belly, a little nonstructural damage to one wing tip, and over course, the prop.</DIV>
<DIV> </DIV>
<DIV>There has been a lot of bad mouthing of MT going on here right now, but my prop got abraded down to about half of it's original diameter without damaging either the engine or the prop hub. That is going to save me much money.</DIV>
<DIV> </DIV>
<DIV>The following is more speculative. I may have uncovered at least one cause of the down pressure switch hang up. We were having one of our down slope wind situations where the air temperature can jump twenty to thirty degrees in an hour or so, and the plane in the hangar was probably at least 30-35 degrees cooler than it was in flight. With that in mind, I tried a little experiment this morning. I went out to the hangar when the temperature was about 35 degrees. With the plane up on jacks, I retracted the gear and left it up while I warmed the hangar as fast as I could with a propane heater making sure that the warm air was circulated through the nose compartment and the cabin of the plane. When the temperature in the hangar reached 80 degrees, I tried to lower the gear "BINGO" it was hung up. This is only one data point and it may not be reproducible, but it worked once for me.</DIV>
<DIV> </DIV>
<DIV>Donald Royer</DIV>
<DIV> </DIV>
<DIV> </DIV>
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