Throughout the 1980s, I had a 1962 Comanche 250. A great airplane. This 250 came with two 30-gallon mains and two 15-gallon wing aux tanks. Eighty-six usable gallons, at about 12 gallons per hour, was a good three hours beyond the capacity of one’s bladder.
Comanches and some others of that era had a different system to check for water in the fuel tanks and lines during preflight. There are no quick drains below the wing tanks; the tanks are drained from inside. A tank selector is located between the front seats. A fuel strainer unit is located just aft of the tank selector.
The preflight procedure was to select a tank, open the strainer quick drain for a couple seconds to drain any water from the line and the tank selected. Then change to the next tank. The fuel comes out below the center of the fuselage aft of the tank selector. Most owners kept a container on the hangar floor below the tube. If you miss the container, you eventually have a hole if the floor is asphalt. In addition, it is difficult to judge water content and from where it came, unless you crawl under and check the results of each tank release.
During my years in Alaska, I heard stories where some pilots during the winter did not get all the lines flushed, water froze and the airplane went down. Therefore, to ensure I emptied all possible water, while taxiing, I had a habit of again selecting a tank and opening the quick drain for another second or so. Moving through the tanks right to left. Then back to left main for takeoff. I just felt more comfortable doing it a second time under power, particularly during the winter. Having said that, like most, my fuel management system on that airplane was always the same. Left main, right main, left aux, right aux, then right main for the approach and landing. Each hour I changed tanks.
My late wife and I made many trips between the Harrisburg, Pennsylvania, area and St. Pete or Melbourne, Florida, to visit family in that Comanche. She sat in the back with a small cooler of sandwiches, fruit and water. She normally read and listened to music through her headset. We had CD player plugged into the intercom that I could isolate. If she wanted me, she would tap me on the shoulder.
Although we could go nonstop, at first she insisted on a stop for a nature break. Southbound it was Savannah. She could stretch her legs and I could get a bag of popcorn. On return, we normally stopped at Fayetteville. It was about halfway and they always had donuts and coffee in the morning. Eventually, I convinced her on nonstop because any stop added an hour to the trip.
From our central Pennsylvania area, the IFR route for southbound through Dulles airspace was via Hagerstown, V501 Martinsburg, direct Savannah – a route west of the Dulles traffic. That worked for years, then Dulles Approach revised their procedures. Unless you filed above 10,000, the routing after Martinsburg was, “…V433 LURAY direct Savannah…” It added a few miles but worse, it kept you directly over the Appalachians and if the wind was out of the west or northwest, you could expect moderate to severe turbulence below 14,000. It is on the forecast about 300 days of the year.
Washington Center was sympathetic and as soon as you cleared Dulles airspace, they would issue direct Savannah. The Center also had the duty prior to entering Dulles airspace to revise your routing if you filed Martinsburg direct Savannah by adding the trip down to LURAY. Once, after I complained to the Center that V433 southwest of Martinsburg was the roughest road on the East Coast, the controller said, “Dulles airspace is the largest restricted area on the East Coast.”
On one southbound, trip to St. Pete we were about an hour out and it was time to change from the left to the right main. Dulles called and changed me to Washington Center. We were south of Martinsburg, approaching LURAY intersection. I checked in with Washington Center, listening for the “…proceed direct Savannah.” Suddenly silence. The engine quit without warning. I had lost an engine before in a Cherokee when a cylinder apparently began eating a valve. That made a lot of noise. This was instant silence. We were over the Appalachians. Terrible terrain. That tank cannot be empty; fuel was right up to the cap.
What seemed like eons but likely, a nanosecond, by muscle memory, I hit the electric fuel pump switch, mixture and reached between the seats for the tank selector. Non-pertinent word! It was on left aux and obviously finished the last of usable fuel. I changed it to the left main detent, and the engine came back to life. We lost about 100 feet and some speed. The controller said something about turbulence. I said, “No I just let too much air in a fuel tank. We’ll be back at 8,000 in a second or two.”
It sounded like the controller chuckled, “…proceed direct Savannah.”
Something interrupted me while quick draining during taxi. I have never figured out what. While adjusting the power settings again, my wife managed to yell, “What happened?”
Now I was Joe Cool, calmly saying, “I just waited too long to swap tanks.”
She said, “Don’t ever do that again.”
In marriage, sometimes it pays to keep quiet.
- An interrupted checklist leads to some excitement - February 7, 2019
Dick, this is why I like simple stuff. Our flight club C150 is “simple stuff”! Downside is you can’t do as much, but I still scratch my aviation itch!
Nicely written article. I can appreciate the roughest road on the east coast part, and trying to find a way around the DC SFRA. We had a “too much air in the fuel tank” challenge recently, which resulted in the vary same comment from my wife. The silence is quite deafening. Gauge and timer said we had a bit more fuel in the tank, and I was trying to use almost all of it. Well I did. Quick flip on the fuel pump, switch tanks, and in about 20 minutes (or what seemed like it) the engine came back on. About 100′ and 10 knots, so it was pretty quick. Thanks for the article. I have heard of Comanche pilots finding interesting ways of either hanging a strainer, or having someone pull the release and someone else hold the strainer. Pretty poor design either way.
I would be a little careful draining the tanks while taxiing. We have a 260B and a oil rolled inside the fuel selector coupled with the drain valve not shutting completely off caused fuel to leak from the drain tube. Had we not caught this on the ground it could very easily caused fuel to continually drain during flight. Our procedure now is the last thing we do before boarding is to check and make sure the fuel drain tube is not leaking. Just something to consider. Safe flying!
Oil should be o ring