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I originally asked the same question on Space Exploration but will repeat it also here:

Before every takeoff and every landing, there are several routine checks which need to be done in order to provide the highest maximum safety to passengers.

But after certain number of repetitions, these tasks can feel as tedious especially if you are flying a plane which goes in "turns"

(Real example of what I mean is commercial line between Prague (PRG) and Frankfurt (FRA) where plane lands, people go out, new people go in and plane goes back. And so on)

How do pilots and other personnel make sure that they actually do go through the check every single time without "It was OK last time, so it will be ok this time. Skip it and say it is ok" ?

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    $\begingroup$ Because if they skip it and it was not ok they can be fired and lose their license $\endgroup$
    – ratchet freak
    Jan 30, 2015 at 10:07
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    $\begingroup$ Because if they skip it and it was not ok they could DIE. $\endgroup$
    – GdD
    Jan 30, 2015 at 10:19
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    $\begingroup$ Yup, as both before me pointed out, it's not even like the can opt out of the checklists. The cockpit consists of two people, one reading/actioning the checklist, the other one monitoring and checking/cross-checking. If you say: "Nah, no checklist today", your copilot is bound to say: "Sorry, but we have to!" Your own life depends on it as well... $\endgroup$
    – SentryRaven
    Jan 30, 2015 at 11:23
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    $\begingroup$ Do they really really not skip checklists, though? Because apparently commercial airline pilots also sleep in flight even when they're not supposed to (e.g. captain at the same time as the first officer), so I'm wondering if the facts are actually lining up with reality. $\endgroup$
    – user541686
    Jan 31, 2015 at 8:57
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    $\begingroup$ @Mehrdad In four years in an airline cockpit I only encountered 1 person who didn't respect checklists. Perhaps not coincidentally he did not make it through his probationary year and was fired. $\endgroup$
    – casey
    Jan 31, 2015 at 22:06

7 Answers 7

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You stay vigilant by having seen things go wrong.

Like Jamiec mentioned the importance of a proper preflight is drilled into you by your primary instructor from day one in light aircraft, and that mentality carries through all the way up to heavy transport-category aircraft: You want to find any problems you can while you're on the ground, because if you take a problem into the air with you it's a decision you can quickly come to regret.

Personally I've found all sorts of "interesting" things on preflight inspections of light aircraft, including (but not limited to):

  • Mud wasps building a nest in the pitot tube
  • Mud wasps building a nest in the fuel drain
    (still don't know what was up with that)
  • Missing screws from a fairing
  • Flat-spot on a tire
  • A tennis ball stuffed in between two cylinders
    (a common flight instructor trick to see if students are doing a thorough preflight)
  • Position light lenses installed backwards
    (another common CFI trick, but this one was actually a maintenance shop screw-up)
  • Various light bulbs burned out
  • Water in the fuel after a heavy storm.

I've also heard some scary stories:

  • Migrating colony of bees hanging out on the tail of the aircraft
    (described as "The tail was literally dripping bees")
  • Flight controls rigged backwards
  • Big gouge in the wingtip
    (acquired by the previous pilot scraping the tip against another plane's tail taxiing in on the ramp)
  • The ever-classic "ran out of fuel because you didn't visually check the tanks"
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    $\begingroup$ I had a bird living in my horizontal stabilizer. We spotted straw during the preflight poking out of a lightening hole that gets exposed while the flight controls are locked (elevator deflects upward). Taped that over and we've been good ever since, but a hell of a shock. $\endgroup$
    – egid
    Jan 30, 2015 at 18:25
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    $\begingroup$ @egid Ooh I forgot about birds nests! Our local birds prefer to nest in the engine cowling (because I bought a tailcone cover to keep them out of THERE) -- only sign of the nest on preflight was one stray piece of straw sticking out of one of the cowl vents, but it was right up between the front cylinders and the exhaust stack/mufflers when I pulled the cowling apart - prime fire-starting position. ("Split the cowl and look for nests" is now standard on my spring preflights. Stupid pyromaniac birds!) $\endgroup$
    – voretaq7
    Jan 30, 2015 at 18:39
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    $\begingroup$ Don't forget ran out of fuel because you were distracted by visually checking the tanks, and you don't know how the metric system works $\endgroup$
    – Phil Frost
    Feb 1, 2015 at 12:53
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    $\begingroup$ My most memorable personal experience was the pair of pliers inside the engine fairing on a single engine piston light aircraft, right by the spark plugs. Now, that's a good reason to remember to do all the preflight checks... $\endgroup$
    – Landak
    Mar 9, 2015 at 20:21
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    $\begingroup$ At least you FOUND the wasps nesting in the pitot tube. $\endgroup$
    – Vikki
    Dec 5, 2018 at 23:02
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In commercial operations the vigilance to avoid complacency is derived from multiple reinforcing actions.

Checklists are often preceded by flows in which you take a logical route through the aircraft panels and perform your checks from memory. These flows are then backed up by the checklist. Checklists vary in usage. One one end of the spectrum you have silent checks performed by one pilot (e.g. the after takeoff checklist may be a silent checklist) and on the other end you have challenge and response checklists where one pilot reads each item and the pilot who accomplished that action reads the status of that system (e.g. you look at the button/light/etc and call its status rather than calling the response from rote memorization).

In an airline cockpit you might fly with the same pilot all month or you may change pilots every trip or sometimes multiple times during a trip. Flying with many different people helps you standardize on these actions as you cannot "get comfortable" with a specific person. Everyone expects everyone else to do the checklists properly and if you don't do it you will get called out. Particularly as a new first officer if you are not doing checklists you are going end up explaining why to the chief pilot and/or training department.

You might then ask why we care so much about policing eachother to maintain checklist usage. The FAA (in the USA) has made a big deal about checklist usage on every checkride you've taken to get into an airline cockpit (at least if you've done your training in the last decade). It has been drilled into you from the beginning of your training. In an airlne environment you will have recurrent checkrides every 6-12 months and captains will have line checks every year and proper checklist usage is among the most basic requirement to pass these checks.

Lastly, every year we sit through a day of crew resource management training and part of that day involves looking at past accidents and understanding what the first thing was that set the accident events in motion (pilot error!). These often serve as vivid examples of how bad things can get if you start ignoring the checklists (among other things).

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    $\begingroup$ Awesome, detailed answer. Also appreciate the comment on flows -- especially useful for emergency procedures, where a certain number of checklist items are expected to be memorized for immediate corrective action (and then verified by checklist, if time/conditions allow). $\endgroup$
    – dougk_ff7
    Oct 29, 2015 at 14:49
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I can't speak for commercial operations, but from a GA point of view, the pre-flight checks and their importance are drilled in to you from your very first lesson. Its is stressed that the Pilot in Command is 100% responsible for verifying that the aircraft is fit for flight before even climbing in to the cabin.

There are a few tricks that are used to stop you falling in to that "Yeah, everything will be fine" mindset and just skipping the checks

  • Not doing the checks from memory, but actually doing them in reference to a physical check list.
  • A prescribed order of checks, starting at a point on the aircraft and moving around methodically
  • The fear of missing something, such as engine oil levels, which gets very serious once airborne.
  • Once carrying passengers, especially nervous ones, they tend to feel safer when they've seen you PHYSICALLY checking the aircraft before flying it.
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  • $\begingroup$ "Not doing the checks from memory, but actually doing them in reference to a physical check list." There is a little controversy about this, because 50% of PPL/CPL holders I asked state they do it differently. They do the items from memory and thereafter verify them with the physical checklist. Must be something that depends on where you learned to fly, because I know it the way you described it, too... $\endgroup$
    – SentryRaven
    Jan 30, 2015 at 11:26
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    $\begingroup$ GA pilots may be more lax, and there are certainly historical cases of missed checks causing accidents (and presumably, therefore, missed checks that they got away with)... Commercial pilots are highly unlikely to get away with it, but it does depend to some extent on the checklist. "Kick all 3 tires" can be verified after the fact on the checklist from memory, whereas a 787 pre-flight cannot. $\endgroup$
    – Jon Story
    Jan 30, 2015 at 13:47
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    $\begingroup$ @JonStory my understanding is that airline crews are taught to use checklists as proper check lists (complete a flow, run the checklist to verify (check) that all required items were in fact completed). For something complicated like a preflight that might mean stopping to review several sections of a checklist (Wing, Tail, Nose, etc. for the external check). The other way of using checklists is to treat them as "Do-List" (point at an item, do it, point at the next item, do that one, etc.) & there's lots of Human Factors research telling us that's not an ideal way to do things. $\endgroup$
    – voretaq7
    Jan 30, 2015 at 15:44
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In short, discipline.

In my case, I learned the discipline to use a checklist for every action on every flight the one time I decided not to use a checklist while taxiing from the fuel pump back to the parking ramp. It was winter, and a snowplow pulled up behind me, so I decided not to use the checklist in the interest of expediency (ha!). I primed the engine, checked the fuel valve, engaged the electrical system, keyed the starter, and the engine responded by firing up and then immediately dieing. Repeat about a half-dozen times, at which point, I finally decided to use the checklist because something obviously wasn't right. Once again, primed the engine, checked the fuel valve, move the mixture to the rich posi--

Oh...I had left the mixture in the idle-cut-off position. Oops.

I've used a checklist religiously ever since then ;)

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    $\begingroup$ Well, I'm happy to see that I'm not the only one this happened too... Once flying the Beech Baron of my boss I also thought I know it all by heart... My boss (and also flying teacher at the time) was sitting beside me, smiling and just letting me desperatly try for like 10mins. $\endgroup$
    – Patric Hartmann
    Feb 1, 2015 at 14:07
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If you do it often enough, it becomes a habit. It then feels wrong to not run the checklist.

The only problem with all that repetition is that while you ran through all the items, you didn't actually do the thing which needed to be done on that occasion.

Case in point: Air Florida Flight 90. One of the checklist items was engine anti-ice. The crew of the accident flight was accustomed to flying in warm weather conditions. In such conditions, engine anti-ice is not necessary or appropriate, so the checklist action/response would always be "off". For the flight in question, engine anti-ice would have been at least a wise precaution if not critical to a safe takeoff, yet the habit prevailed and the takeoff was attempted without engine anti-ice. Without anti-ice, sensors were likely blocked with ice, causing incorrect readings on gauges indicating engine performance. This led the crew to apply insufficient power to accomplish the takeoff.

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  • $\begingroup$ Aggravated by the aircraft needing more power to take off than it normally would, due to the wings also being contaminated with snow and ice. $\endgroup$
    – Vikki
    Dec 5, 2018 at 23:04
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For me, it's simply common sense. It's like with driving a car: I have been driving for 13 years now and still drive as carefully as I did when I started. I have had one accident in that time; the other car and I skidded on a smooth road. But, we were both driving carefully (roughly 30kmh/20mph in a 80kmh/50mph zone) so nothing more than car body damage happened.

You cannot always prevent accidents by being careful but you can always attenuate the consequences.

I don't want to die nor do I want my guests to die from my negligence, so I am not negligent, be it with the car, the plane (for which I have not long had my licence) or even simply with the windows of my apartment on the 4th floor; negligence kills.

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    $\begingroup$ You seem to be confusing driving slowly with driving carefully. They're completely orthogonal. It's possible to drive carefully at 70mph and to drive carelessly at 7mph ("Look, ma! No hands!"). I'm glad your crash wasn't serious but, arguably, the fact that you crashed at all (and that it wasn't entirely the other driver's fault) indicates that you weren't taking enough care. $\endgroup$
    – David Richerby
    Feb 2, 2015 at 19:19
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    $\begingroup$ The only way to make sure you don't have an accident is to never drive a car. Even the law says so: You're always responsible and to a certain extent accountable for just driving the car. No matter who did what in an accident: You always pay at least 25% of the damage simply because it's your fault to have taken the car. $\endgroup$
    – Patric Hartmann
    Feb 6, 2015 at 12:13
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    $\begingroup$ I have a checklist for stopping at stop signs. People often think they come to a full stop, but from the outside, if you watch their wheels, they never completely stop turning. So what I do is this. Don't look to see what the traffic is like on the cross street until you've come to a full stop. When you believe you've stopped, add a little more pressure to the brake. If you really stopped, nothing happens, but if your wheels are still turning, there will be a slight jerk. NOW check the highway for traffic. $\endgroup$
    – Howard Miller
    Oct 27, 2015 at 0:06
  • $\begingroup$ @PatricHartmann: So if someone pulls out in front of you too close for you to stop, it's still your fault??? $\endgroup$
    – Vikki
    Dec 5, 2018 at 23:06
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    $\begingroup$ @Sean : Here in Switzerland, where I currently live, the answer is pretty much "yes" if it's a pedestrian, a bike or a motor bike (here with exceptions). If "someone" is another car, then the situation may vary. There are "standard situations" (e.g. a rear-end with no injuries and only minor damage) where there's no actual investigation and the perpetrator's insurance just pays. But when something major happens there is almost never a 100% fault on only one side. However, it seems not to be 25% anymore (or I got that wrong) according to the insurance guide here: svv.ch/de/ratgeber $\endgroup$
    – Patric Hartmann
    Dec 9, 2018 at 20:41
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On commercial flights, key checklist items are forced by using a procedure call a "cross check". The one pilot must "challenge" another for those specific check list items. For non-cross checked items, pilots have discretion to implement checklists as they see fit.

Each pilot has their own practice. Some are sloppy and do nothing. Others fastidiously follow every item. Most commercial pilots tend to blow off most checklist items, especially anything outside the cockpit. For example, I fly American a lot and when the flight crew arrives I always watch to see if they do a walkaround and I have NEVER seen them do it. I complained about this to one of the top flight instructors at American and he said, "Well, they are supposed to do the walkaround." Yeah, they are SUPPOSED to, but do not do it.

It comes down to the personal discipline and attitudes of the pilot involved and how pressured they are to get the plane up in the air and on schedule.

On non-commercial flights and cargo flights often crews will become very lax. For example, in 2014 a Gulfstream crashed at Hanscom airfield killing everyone on board because they tried to takeoff with a gust lock engaged. This is impossible if you do even a minimal checklist because a control check is like the #1 or #2 thing on any checklist. A review of the tape showed that the crew in that case did ABSOLUTELY NOTHING verbal for cross checking. Furthermore, a review of the flight recorder for the aircraft showed that the crew had NEVER done a control check in 98% of the flights in that aircraft. Such laxity is not unusual in non-commercial flights.

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    $\begingroup$ What, specifically, do you mean when you say "blow off" a checklist. $\endgroup$
    – Terry
    Mar 10, 2015 at 7:08
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    $\begingroup$ @Terry I explained in my answer. Commercial pilots blow off checklist items, especially if they are time consuming or would involve walking around in the cold, like doing the walkaround. Multiple aircraft have crashed because the pilots did not check wing ice, and all they have to do was walk down the aisle and look out the window. Now that's lazy. $\endgroup$
    – Tyler Durden
    Mar 10, 2015 at 12:59
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    $\begingroup$ @Terry According to the AA instructor I talked to, a walkaround is a company-required checklist item. The undercarriage and other critical items on the underside of the aircraft (fuel ports, flat tires) should be checked on ANY aircraft whether it is a 747 or C172. All Boeing manuals have detailed instructions on performing a pre-flight walkaround. I know ice is "above the wing". Did you even read my comment? I said you have to WALK DOWN THE AISLE to examine the wing and leading edge. How many pilots actually do this? Not many. $\endgroup$
    – Tyler Durden
    Mar 10, 2015 at 19:11
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    $\begingroup$ Let us continue this discussion in chat. $\endgroup$
    – Terry
    Mar 10, 2015 at 20:15
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    $\begingroup$ @TylerDurden actually our argument is "we have 1000's of hours in commercial cockpits and have never witnessed gross checklist misuse" where yours is "there are a few accidents and my numerous anecdotes which mean no one uses checklists". Sure, there are a few bad apples, but they are the rare exception, not the rule. $\endgroup$
    – casey
    Mar 11, 2015 at 1:32

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