Learning Experiences: 07/04


Running Out of Gas
Unfortunately, running out of fuel is still not an uncommon cause of private aircraft mishaps. I was flying home from a relaxing two-hour flight with about 30 minutes of fuel left as my home field came into view. When I was five minutes from the grass strip, my engine suddenly quit very abruptly, as if it had run out of fuel-it had. The first thing I did (correctly) was to establish the best glide angle and head straight for the airstrip. When I was less than a mile from the runway (downwind, as it turns out) and 2000 feet high, I started my descent. This was the wrong thing to do. I made a near-perfect power-off glide right down to the ground, 10 feet short of the runway, tearing off the main gear in the landing. The aircraft came to a rest after skidding 50 feet on its belly with no serious injuries to its pilot.

From this experience, I have gleaned several lessons:

1. Understand the difference between usable fuel and total fuel. This was an amateur-built aircraft where the fuel pickup was at the rear of the fuel tank. The unusable fuel during actual flight had never been determined. On the ground, this taildragger could use all but the last few ounces of fuel from the tank. In level flight, even a gallon left may slosh forward, becoming unavailable to the engine.

2. When faced with an emergency, DO stay calm and tell yourself, Ive practiced this before and know I can do it.

3. Do not waste altitude until you are over your intended landing site if you dont have an operating engine.

The aircraft was repaired and has not run out of fuel since.


Maintenance Assumptions
Those of us who fly know that an assumption is also something that can make you dead. Assumptions also get harder with age. They fossilize into immutable fact until shattered by another immutable fact going in the opposite direction. The shattering of the following assumption didnt do any significant damage, but it shows that there is almost nothing that should not be reviewed and questioned from time to time.

Near the end of the last millennium, I joined a flying club. The engine in one of the planes was over TBO and we soon had a failure signalling it was time for a replacement. There was a lot of discussion about how we would be getting a factory remanufactured engine with 90% new parts that was the functional equivalent of a new engine and with a zero time logbook.

I volunteered to help the FBO install the new engine just for the experience. A new tachometer was being installed at the same time and I was there for the discussion about what to set it to. Since it was a new, (essentially) zero-time engine, it was decided to set the tach to zero so all times going forward would correspond to the engines life cycle.

A couple of years later, I took over management of the plane as maintenance officer and finally got to see the logbooks. I noticed that the engine total time was shown as several thousand hours, approximately that of the airframe. I thought they must have just mixed up the figures.

Then, the engine experienced an unexplained lifter failure that damaged the camshaft at about 1000 hours since it was installed. Our decision to have it rebuilt was largely based on its being a relatively new engine and our plan to do a full overhaul at TBO.

After the engine was back in the aircraft, I filled out an oil sample slip at the first oil change. The IA at the FBO brought it back out to me and said, This is wrong. Its 1050 hours SMOH but you have almost 10,000 hours on the engine.

No, way, I said, That was a factory reman in 1999. He went back and got the first engine logbook and opened it up to the first page, the one that came with the engine from the manufacturer. It said very clearly, Factory overhaul at 8500 hours.

I was stunned. It was like finding out that my wife was five years older, had an assumed name and had spent some time in the pen. All the discussion and years of assumption left me so sure this was a zero-time factory reman that I never thought to go back and look at the first page of the logbook.

Every member who was there at the time with whom I have spoken has confirmed that they believed it was a zero-time factory reman. The treasurer looked back through the newsletters and bills. The newsletter refers to the engine as a reman but the price quoted and paid is the price for an overhauled engine, not a reman.

The manufacturer will not overhaul an engine of the age this one will be when the TBO clock runs out, so well be looking at spending more money in 1000 hours than we planned. Were flying behind some older components than we thought; the premature lifter or cam failure may well have been due to a cam that only met service and not new-dimension limits being installed in the engine. That would have been acceptable for an individual owner flying 50 hours a year but not a club flying five times that much.

The people who handled this are long gone so we cant ask why they told us quite clearly one thing and did another. It just goes to show, there is very little that is not worth verifying.


Shooting the Gap
Recently I flew to a business appointment in Stockbridge, Mass., the most convenient airport for which was Pittsfield (PSF). This was my first flight to this area, so I was particular about my planning.

The chart implied that a first-timer to this field might have to do some guessing as to where the airport is due to the hills surrounding.

I enjoyed a smooth fingertip-flying cruise northbound from my home field at Islip (ISP), on Long Island. I began my descent about 20 miles out of PSF. Then, with a GPS distance of eight miles remaining, I surmised that the airport had to be just over a 2000-foot-high hill ahead and to my left. There were also hills to my right, so I continued down between them.

Sure enough, as I was about to fly directly through the center of the gap, I saw the Pittsfield airport tucked in behind the hill to my left.

Just as that thought was delivering its feeling of accomplishment, I was slammed with a tremendous downdraft that seemed to come from no specific direction. I immediately realized that I had made a truly dumb mistake in my approach plan.

After about five minutes of turbulent positioning in order to complete the pattern and get to the runway, I finally landed and was thrilled to get out of the airplane.

The guy at the FBO desk said with a smile, Were a little tricky the first time, arent we?

My next arrival at this airport will surely take me over the hills and then down around into the pattern. The lesson here is to be extra cautious near mountains of any size, especially when in unfamiliar territory.


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