Preflight Inspections – A Mea Culpa

January 2017 - At the risk of sounding “preachy,” the importance of using checklists remains a constant in aviation, and this is reflected in the countless articles on the subject. Combined with a checklist, a proper and complete preflight inspection can turn up myriad issues. Coffee shop chatter often describes times when, after an annual inspection or other maintenance work, tools or other foreign object damage can turn up in the most unlikely places. Items such as control locks, pitot covers, or even tiedowns missed in a preflight inspection can result in dire consequences at worst and embarrassment at best. I had a short trip that ended well but not because of any good planning on my part. The self-inflicted drama involved was caused by a cursory preflight done without using a checklist … in a borrowed plane.

It was another beautiful day here on the West Coast, and I convinced my wife, who was not big on the idea in the first place, that we should go flying to look at the tall ships in nearby Steveston Harbour. I had recently checked out in my friend’s Citabria and had the loan of it for the afternoon.

Confident that I knew what I was doing, I did the preflight walk-around, checking fuel and oil, moving all the bits that are supposed to move and trying to move some that aren’t. Once inside and buckled up, I started the little Lycoming and let it warm up while I checked the ATIS and got taxi clearance. All of this while not using the checklist located high up on the side of the cabin. A normal run-up followed with mag’s checked and pressures confirmed. I called the tower and received clearance to the active with a backtrack to the end of our 2,100-foot runway.

I pushed the throttle to full power and began the takeoff roll, and it all was so darned normal until I got airborne. Then the engine began to miss — cough, catch, sputter etc. — and we weren’t climbing. If this has ever happened to you, you know that this is not a good thing.

Landing straight ahead had its own problems as the runway, most of its 2,100 feet already behind me, ended at a highway with all the associated fences, berms, ditches, and traffic that involves. I continued ahead, hoping to land in a field across the road. I pushed the nose down to maintain some airspeed, and the engine surged back to life. As soon as I pulled back on the stick to try and gain some height, it quit. This cycle of start and stop continued, seemingly controlled not by the throttle, but by attitude.

As it happened, I was able to maintain about 200 feet and minimum flying speed with the engine alternately surging and quitting. I called the tower, and they cleared me to any runway. I managed to complete the never-to-be done turnback to the departure runway by using rudder only to flat turn, avoiding any stall-increasing bank. However, when the runway came back into view, there was an aircraft about midway along on its take-off roll. So much for that idea! I continued the turn past the hangars and towards a hay field that had some potential if the engine quit altogether. All through this epic, the Citabria was pitching up when it got fuel and sagging down when it didn’t. I went past the tower, around the barn, and successfully landed to the west on the grass runway. Where was the wind, you ask? No idea!

Once on the ground, the engine ran normally. We taxied back to the hanger, and I tried several full power run-ups, and everything seemed fine.

I shut everything down and tried to figure out what had happened and why.

As I looked around the cabin, it soon became clear what the problem had been. There under the left side of the panel was a fuel valve firmly in the off position. It seemed very tight when I turned it on, but it did move slowly. I restarted the engine and did another run-up, and everything seemed to work fine. After convincing my very brave wife that everything was indeed okay, we again took off and had a very enjoyable hour-long sightseeing trip.

A subsequent investigation showed that the factory swivel connection at the fuel valve had been replaced by a homemade part sometime in the aircraft’s history. The bronze valve had become stiff, as they do with age, and this bogus fitting had bent. The bending combined with the stiffness resulted in the valve not shutting completely off. This allowed enough fuel for a run-up and taxiing but not enough to sustain take-off power. Had the valve shut off properly, the engine would have started but run out of fuel before I got to the run-up bay, thus alerting even the densest pilot that something wasn’t quite right.

Two previous owners of this Citabria had never used the fuel shut-off and, of course, never had a problem, as the valve was always full on. The current owner was in the habit of shutting off the fuel. He had previously owned a Champ and shut the fuel off after each flight due to a leak through the carburettor. I have never shut off the fuel in my Stinson and never even thought about the valve. However, had I taken the time to use the printed checklist stashed in plain view up high on the side of the cabin, none of this would have happened.