Saturday, July 30, 2005

And the forecast is........

.... fog. Until the thunderstorms start. That's about normal for the last two weeks. So this makes it 6 consecutive scheduled flights I've had to cancel.

After speaking to the FAA's investigator, it seems the retelling of their conclusion was slightly off. I was puzzling at how they could expect the plane to put that large and long a scar in the runway, go through 150 feet of grass, then crumple the nose gear, then still have enough remaining kinetic energy to flip over quickly. The scar on the pavement was deep enough to indicated to me that had we done that, the plane would only be going about 30 by the end of the pavement. The ground past it would have surely taken a good scar if the pavement was grooved from whatever caused that. My best guess is, their scenario with the airspeed I know we had at the time, would have left us hitting the hill at no more than 10 miles per hour. If we had gotten to the hill at all.

These things were a puzzle to me, and I had to wait a while before he returned my phone call. He decided that the plane must have been traveling significantly faster than I claim. This is simply not possible. The top permissible speed for that flap setting was 60 knots. Had we been there at any point, I would have forced DC to abort the approach and go around.

That has been one of my issues with the plane since the beginning. In a power-off glide, the plane needs at least 50 knots of indicated airspeed to have enough kinetic energy to flare without hitting hard. But exceeding 60 is too much. So only a ten knot airspeed range is acceptable, without using power to control the descent rate at the last minute. In my old Cessna 172, also with 40 degrees of flap, there was a 30 knot range, and more inertia to hold speed constant.

When the investigator returned my call, I asked a few questions, and gave him more details he was wanting. Since our versions didn't match, I wanted to know if he would like any sort of addendum filed. I also wanted to head off any concern about the aircraft documents. He was a little miffed, I was told, that the airworthiness and registration documents were not still aboard. DC had taken them out, not knowing he shouldn't, and I never saw him do that. Otherwise, I was trying to get some insight into his mindset, and make him aware that I wanted to cooperate in any way I could. Even when fault is assigned, they often only want the pilot to admit to making a mistake. Arguing with them is generally disadvantageous.

The four days since the crash have been helpful to me though. I've come up with many very specific questions in my own mind about what I would have to see on the scene to indicate one type of scenario or another. I know what could be found to prove me right. I also know what would be found if they were right.

1 Comments:

At 6:41 PM, Anonymous Ruth Holman said...

Hello

I hope that the FAA examiner looks again at what happened- does it seem to you he is jumping to conclusions?

Anyway- the lesson.. remember I had had no prior of flying or flight and did not know better about implications of things that might have happened. I think it was my 3rd or 4th lesson. We were doing the engine run-ups when the C152 (ZK-ELV, known as ELVis) ran very roughly on the left mag. We increased the rpms to see if that would clear it but it still ran rough. Idled for a few more seconds, increased the rpms and it seemed to clear. Continued thru the DVA's then taxiid for takeoff. It seemed to take a looong time for the plane to lift off and actually settled back down very briefly, so we would have used more runway than normal. Finally lifted off, then at about 200 ft the engine sounded real funny and the instructor said "I'll just take control for a bit" a couple of seconds later everything sounded fine and we continued on- doing stalls and he even did a spin to lose height on the way back down. When we landed and taxiid in, the other instructors at the aero club had heard the rough running of the engine (we were maybe at the far threshold of the runway at 200 ft by then)and ran out to have a look. I also found out we had taken off with a quartering tailwind, that was why it took so long to lift off. A couple of people I talked to after (remember I was totally ignorant of what quartering tailwinds would mean to performance etc)said that with the engine running rough at engine run-ups, it was foolish to take off with the tailwind, as had the engine continued to run roughly, we would not have been able to make a safe landing (houses etc in the way). Also, to continue on to do stalls etc was foolish too. Now, possibly if it was 1 mag sticking, we could have switched to the other mag and made it back OK to land - but I also know there are other reasons for engines to run rough. What are your thoughts on this? Is it a big deal or as my instructor said, it wasn't a problem? I think it was just the reactions of those other people (1 a high hour glider pilot and senior instructor and the other a high hour private pilot)who unsettled me on this.
Ruth

 

Post a Comment

<< Home