For every item on a preflight checklist, there is a pilot who overlooked it. Once is usually enough, especially if the oversight led to traumatic or embarrassing consequences. Some pilots skip entire checklists with malice aforethought--a different breed entirely. Postflight checklists also get disdainful treatment, as anyone who has come out to fly the next morning and found a dead battery and master switch on knows.
The last thing any pilot needs is another checklist. But for now let's add one to your pilot's operating handbook and call it, "Items You May Have Forgotten on the Previous Checklists." This checklist's items are more questioning than those on standard checklists. It is organized differently too, divided into three categories: irrevocably dangerous items; those requiring prompt action, and merely aggravating--but potentially hazardous--items.
Group One
1. Fuel quantity--how much? Are you sure?
You checked the fuel gauges. Almost full. You removed the fuel-tank cap and looked inside. If you fly high-wing aircraft, this means you had to climb up to the wing. You could see and hear fuel. Did you measure the amount? If the answer is anything but "affirmative," this item has yet to be completed. You didn't climb up and check because there is no step on your aircraft's fuselage, or because your lower back hurts from yesterday's tennis match? Call the fuel truck--there's a ladder hooked to the back that you can use. For further encouragement, search accident databases under "probable cause: fuel exhaustion, pilot's inadequate preflight preparation."
2. Fuel filler cap--secure.
As long as you're up there, please tighten the cap. It would be a shame to take the trouble to verify the fuel quantity and then have the gas siphoned from the tank in flight thanks to a loose or unreplaced cap. Don't let your haste to get airborne, or the impatient look on the line attendant's face at your having appropriated his ladder, or the magnificent sight of that jet taxiing in, trick you into forgetfulness. Remember, if you fail to do this and something goes wrong, don't even think about blaming anyone else for your lapse. It's your responsibility, Captain.
3. Fuel--check for water, sediment, and fuel grade. Do it!
Admittedly, this isn't as easy as it once was. First, it's February, and it's cold outside. Second, the barrel where you must dispose of fuel samples is located on the other side of taxiway Zulu and you're standing near taxiway Alpha. Besides, any water in the tank would be frozen, right? Wrong, if the airplane is housed in a heated hangar. Could there have been water somehow introduced to the fuel supply? Besides, you need to check the fuel grade anyway. Yours would not be the first training airplane accidentally fueled from the jet-fuel truck. Not only would you enjoy a minimum of flight time when taking off on jet fuel, but do you have any idea how complicated things get at an airport after a fuel contamination incident? It's a huge headache that involves rounding up any airplanes that may have been misfueled. On the bright side, you will be a hero if you catch a mistake and save a life.
4. Control wheel lock--remove.
Really, if you are going to fly today, we strongly urge that you check this item again. Guaranteed--doing so will enhance your piloting experience and preserve the structural integrity of objects and persons who may happen to be standing near the end of the runway when you go. Forgetting this step can have spectacularly quick and nasty results. Also, this is one of those chain-reaction type items that, if not checked, proves that there are other things you did not bother to do.With a locked control wheel it obviously isn't possible to check the freedom and security of ailerons and elevators. It means that you didn't do much of a walk-around inspection because moving the control surfaces is part of that process too. Very incriminating item. The amazing thing is that someone that lazy has enough ambition to take the key to the aircraft out of his pocket and insert it into a door lock or ignition in the first place. Or to rotate--which you will immediately discover is impossible to do. Unfortunately, you discover this when you are barreling down the runway at or above rotation speed. You add backpressure to the yoke and nothing happens. At least, nothing over which you have any control. The airplane may fly without any assistance from you, or it may opt for high-speed taxiing. Trim, center of gravity, and fate will decide.
The yoke, meanwhile, stays right where it was, because either the control wheel lock or perhaps a hard-to-see nail someone is using as a replacement--one of the worst ideas ever perpetrated as a quick fix--is still inserted in the control column. It should have been removed at the very beginning of all these checklists. In the Cessna 152 POH, for example, removing the control wheel lock is the second item on the first checklist. Enough said, the trucks are probably rolling by now, and so is the van painted with the local TV news logo.
5. Cowl plugs--remove.
Runup was fine, takeoff routine. Now you are climbing to altitude. Despite the bitter cold you were pleasantly surprised at how little time it took your engine-oil temperature gauge to come alive. Unfortunately the trend is continuing, with the temperature indication continuing into uncharted territory. At this point the oil pressure gauge may or may not corroborate the anomaly with a display of falling pressure, leaving you to wonder whether the oil is really this hot and the engine about to blow, or if you simply need a new gauge. That's when you remember the cowl plugs....
6. Got flaps?
One thing flight instructors remember when flying with certificated pilots is that everyone learned different preflight habits concerning flaps. Some pilots learned to fly "the old fashioned way" in a Cessna 120 or other flapless flying machine, making the situation more unpredictable. Of those who did have flaps to think about, inspection methods vary. Checklists are not always helpful; some popular trainers' operating handbooks (Cessna 150, 152) do not even mention flaps until the takeoff checklist, when they may be partially deployed for maximum-performance departures. So people invent their procedures. Maybe that's why it is not uncommon to observe an airplane taxiing out for takeoff with flaps fully deployed. Probably the pilot deployed them immediately after turning on the master switch for the first time--questionable anyway if battery power to start a cold engine is in doubt. But more important, if the flaps-down condition goes unnoticed, the takeoff could quickly go out of control or the airplane might fail to outclimb obstructions, making this a potentially fatal lapse. Especially on a high-wing airplane it is hard to imagine those big flaps going unnoticed during taxi, but it happens.
7. Doors--closed, latched.
Usually we think of cabin doors when considering this item. But baggage compartments and the small door where you add and measure engine oil also open and close. It is a pity that securing cabin doors, in particular, must be included on a list of the most dangerous preflight chores that pilots overlook. The case history is replete with instances where doors led to pilot distraction followed by stall/spin accidents when the pilot paid more attention to closing the door than flying the aircraft. Do check your cabin doors, and give those other doors a second look. Remind yourself that should a door pop open, fly the airplane first. Frequently the open door requires no further action until the aircraft is stabilized in cruise flight. On that, review your POH.
Group Two: fast action items
8. Magnetos--set on both?
Run-up was fine, with rpm decreasing the same amount when you tested the left and right mag, within specified limits. Then you moved on to check the carb heat. Reasons vary--from distraction to pretakeoff giddiness--but sometimes when moving on to the carb heat check, pilots forget to set the mags back to "both." Takeoff commences, and the reduced power of single-mag operation makes itself apparent at a critical time, confusing the pilot or constraining any required maximum-performance climb.
9. Gust lock--removed?
Unlike airplanes that were flown with control-wheel locks still in place, airplanes that depart with a rudder gust lock still installed may fly without a complete lack of controllability (especially if the pilot's use of rudder to coordinate control inputs is flawed to begin with). But try landing in a crosswind or recovering from an inadvertent stall that is progressing to a spin, and it is a different story. Nor will that big gust lock, often with a bright-colored flag attached, go unnoticed from the control tower or the ramp. The tower might feel obligated to report it to the FAA. For more examples of pilots who came to grief over unattended gust locks and fuel caps, see "Safety Pilot: Make Up Your Mind Quickly" at AOPA Online.
10. Pitot tube cover--removed?
Like the foregoing item, this could lead to a scare or an accident, but a few minutes of training in the ability to fly by feel when instruments are telling lies, and staying calm, will keep trouble away. If the pitot tube is covered, there will be no usable airspeed indication. Pilots attempting to take off have been known to panic or run aircraft off runways waiting for the obvious to be displayed on the gauge. Such a shame! If power is strong and pitch appears normal for the climb, and if control pressures feel normal, fly the airplane first (if a safe abort is not possible) and worry about the gauge later. Use your familiar power-pitch-feel combinations, and bring it around for a safe landing. Ignore, or cover, the instrument.
Group Three
Last are those forgotten preflight checks that usually only bring a sheepish smile. But they remind pilots how easy it is to let down your guard.
11. Mixture--rich?
What's wrong with that blue four-seater on the ramp? The pilot did a thorough preflight and loaded his three passengers and baggage aboard with care. But try as he might, he cannot get his airplane started. He cranks, pauses, cranks again. Nothing. Now he is on the radio, requesting help. A flight instructor or mechanic comes over to the pilot's side window and points to something on the panel (the red mixture knob). A moment later the blue aircraft and its red-faced pilot are taxiing out for takeoff.
12. Tiedown, wheel chocks--disconnected?
Separation anxiety is one thing, but if all the power in the world cannot free you from your parking space, there can only be one reason. Do the right thing! Shut down and separate the rope from that last wing or tail tiedown ring. Yes, people will notice. But resist the temptation to get out with the engine running and the brake set--or worse, with a passenger in charge. If you don't think you will face that temptation, here's a promise: You will.The same goes for wheel chocks. One difference is that an airplane being restrained under power by chocks may free itself with a sudden leap, leaving you pointed who knows where, with the engine at high power. Beware.
13. Seat belts, harnesses--adjusted, locked.
You would not be the first pilot to realize only upon doing your prelanding checks that you had never fastened your belt and harness. A more jarring and distracting way to discover the problem is for a loose belt, dangling outside the cabin door, to come alive suddenly in the slipstream, slapping loudly against the fuselage.Any pilot has seen or experienced some of the 13 lapses described above, and others. Follow your checklists--all of them. Check once, then check again, to avoid becoming the next victim of these all-too-recurring omissions.
Dan Namowitz is an aviation writer and flight instructor. A pilot since 1985 and an instructor since 1990, he resides in Maine.
Want to know more?
Links to additional resources about the topics discussed in this article are available at AOPA Flight Training Online.
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