Partial Panel for Real

Today I had my first real instrument failure. I started out on a cross country flight to try out my new Lowrance AirMap GPS. The GPS was still looking for satellites while I was taxiing, so I thought I’d just go ahead and fly and figure out where to put the portable antenna.

As I started down the runway, I noticed the airspeed indicator wasn’t moving. The lowest speed it shows is about 30 mph, so with a headwind I have to get close to takeoff speed before the needle moves. I lifted off, and it stayed on zero. I had heard about people flying with the airspeed indicator covered as a training exercise and wondered what it would be like to land that way. I was about to find out, since I wasn’t going to leave the airport area with a primary instrument not working.

Luckily there was no other traffic in the pattern, so I made my normal radio announcements without mentioning my problem. Without knowing my airspeed, I had to guess when to put flaps down and whether my approach speed was right.

I came in high and fast on purpose, figuring it was better to use more runway than go too slow and become a stall/spin statistic while turning final. Of course, the stiff headwind I took off into shifted and now I had a direct crosswind of 12 knots, with the windsock almost fully extended. Crosswind landings aren’t my strong point, but it’s interesting how much my flying can improve in a serious situation. It was one of the better ones I’ve ever done. I wish I could do as well when my CFII is with me.

This wasn’t an emergency, but there was a chance of misjudging the speed and undershooting or overshooting the runway, or making a hard landing. The irony here is that if I’d gotten the GPS working first, it would have at least shown my groundspeed, which I could have used as an estimate of my airspeed.

But I’m glad it happened this way, because otherwise I’d be thinking “the GPS saved me”, instead of “I handled an instrument failure properly”. As I was going around the pattern, I realized how important that indicator is. It would have been much easier if any other instrument had failed; pattern flight without having a display of heading, attitude, vertical speed, even altitude would have been easier.

The other instruments worked fine, so I knew my problem was a blockage in the pitot system or the indicator itself. Unlike many Cessnas, my plane’s pitot tube has a cover attached, a little flap that hangs over the end of the tube and moves out of the way when the air flows fast enough. I thought the cover would keep out insects. I couldn’t see anything blocking the tube.

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