Details, Details

A postflight inspection is as important as the preflight

July 1, 2004

One of the most important lessons that a young pilot learns is to properly preflight an airplane, and with good reason. Would you really want to get airborne knowing that you had not checked the oil or the security of the fuel caps?

Much attention is given to checking details before flying. It is just one of the many ways to break the accident chain and enhance safety. Accidents that have occurred because of a poor preflight include taking off (or attempting to, anyway) with the control lock installed, taking off with one or more tiedowns still attached to the plane, or simply departing, on a very short flight, without fuel or oil.

But what do you do when you are finished flying? Relatively little emphasis is put on the performance of a proper postflight inspection. Just because you did a stellar preflight does not mean that the next person to use the airplane will do one as thorough as yours. And just because you didn't see someone else on the schedule after your flight does not guarantee that the airplane is finished flying for the day.

If the airplane you fly does not come with a detailed postflight checklist, you can improvise. Use the published preflight routine as a guide and change it as necessary — obviously, where it says, "Remove tiedowns," you will want to attach the tiedowns. You can certainly add fuel, and you can wait a few minutes to let the engine cool down and the oil settle, and then check the oil level. This will give you the added benefit of tracking oil consumption.

What else are you looking for on a postflight walk that you might not catch on a preflight? A few things. Believe it or not, it is possible, even in a small airplane, to hit a bird and not know it. It's unusual, but it can happen. If the bird hits one of your antennas, it may break the antenna loose or take it off completely. If you hit a large bird or a flock of birds (the kind of bird strike you can't miss), you will want to survey the damage to the skins of the airplane. It may appear to you that the airplane is safe to fly, but it may not be. On the other hand, the opposite holds as well, and you should try to have a mechanic give you some help if possible. Bird strikes can be messy affairs, but often the mess looks worse than it really is. If you are flying a retractable-gear airplane, and the bird hits a gear door, check the door to see if it is loose; you may hear it in the slipstream after the collision if it is.

Your postflight inspection also may reveal any new leaks from the oil or the fuel system. One of the benefits of having colored fuel is that you can't miss it when it leaks onto your paint. Tires often get short shrift from pilots. As much as airplane tires look like those on other vehicles we use, they are different. For starters, tires on airplanes are used for a very small percentage of our operations, and when we land they are subjected to some pretty extreme loads, especially if the plane is a trainer being abused by students learning to land. The tread wear should be somewhat even on the tires, and surface scuffs are normal. What you need to look out for are new, deeper cuts. Anything that exposes tread is a red flag and should have you reporting the discrepancy to the mechanics. A blowout on landing can lead to an early exit of the runway. Cuts in the tire are most likely caused by a piece of metal left behind by another airplane. If construction is taking place on or near the airport, a nail may show up. Because aircraft tires rotate faster than car tires, the aircraft tires have more energy and can be subject to more damage from a smaller piece of debris. If the airplane can be moved, roll it to check the underside of the tire as part of your postflight inspection.

If you are doing your walkaround after landing, and you see some new, unexplained damage to the paint, especially around rivets, you may want to get it looked at. It's one thing to have paint chip off from normal wear and tear, but you want to make sure that what you are seeing is not a sign of hidden damage such as corrosion or fatiguing metal.

Sometimes you see something on a postflight inspection that you'd never notice in flight, but that could be dangerous. I landed a jet one time that handled perfectly normally in flight, but when we got to the chocks and I did the postflight, there was a thin but steady stream of hydraulic fluid coming from one of the landing gear wells. Looking at the ramp in the direction we had come from, I could see that the trail continued out of sight. It turned out that the leak had developed just a few minutes before landing. Had I missed it or had it gone unnoticed by the next crew, a serious in-flight emergency might have developed.

We often do not check the landing and interior lights prior to flying unless the flight is at night. But you never know when your flight may extend into nighttime hours, and if a landing light has come loose or has been broken by a bird, it's better to find out when you don't need it than when you do.

While taxiing in, flip the magneto switch from Both to Left and then Right. If a mag has failed in flight, you may not have noticed it. If you catch it now it can be fixed before your next flight.

Before leaving the airplane, you absolutely must do two things. The first is to turn off the master switch. Too often, pilots leave the master on and run down the battery. One way to help avoid this is to leave your beacon light on. That way, whenever the master is on, you will see the light. It will also advise other people on the ramp that you may soon start your engine. The second thing you must do is to tie down the airplane. The first time you forget to do it, the odds are that nothing unfortunate will happen. But if you make a habit of leaving the airplane unrestrained, eventually it comes back to bite you, either because of unexpectedly high winds or other airplanes. Several years ago, some airline mechanics taxied a turboprop to the run-up pad to do a full-power runup following some engine work. In coordination with the control tower, they faced the airplane into the wind, which happened to be with the tail toward the ramp. The lone general aviation airplane that was not tied down was a Cessna 152, and it got blown around the ramp and was extensively damaged. It doesn't just happen to small airplanes, either. In high winds, an airliner can be weathervaned. My company has had a couple of airplanes get damaged over the years because of wind. The company policy is for the ground personnel to put chocks under all the wheels when high winds are forecast, but if the winds are unexpected or the policy is not followed, then damage can result.

The flight doesn't stop just because you are done flying. Pay as much attention to the inspection at the end of the flight as you do to the one at the beginning. If you are an owner, you can save time by fixing problems immediately. If you are a renter, the flight school and the other pilots will appreciate your attention to detail. Consider it an early preflight.


Charles "Chip" Wright, AOPA 1086994, of Hebron, Kentucky, is a CRJ captain for Comair.