During the pre flight inspection, usually the copilot checks many parts of the aircraft. Which are the parts and Why do they check them?

  • 3
    $\begingroup$ Chapter 3.3 of this document is a detailed explanation of what is done during the pre-flight inspection. $\endgroup$
    – mins
    Commented Dec 29, 2015 at 18:01
  • $\begingroup$ I have also seen the captain do his own walk-around after the FO has finished. I don't know if that's usual protocol or if those particular captains were just going the extra mile for safety. $\endgroup$
    – TomMcW
    Commented Dec 29, 2015 at 20:12
  • $\begingroup$ Vote to leave the question open. Although the question seems to be "too broad" it has very concise answers. (We used to have a clear checklist for the walkaround) $\endgroup$
    – user23573
    Commented Jan 4, 2016 at 7:31

3 Answers 3


Many things are checked on a walkaround. The pilot-in-command should do the walkaround, not the co-pilot. The main classes of items are as follows:

structural integrity; the aircraft must be sound and undamaged and ready to fly

sensors; sensors such as antennas and gauges should be undamaged and not have anything blocking them or adhering to them

clean flight surfaces; the control surfaces and flight surfaces must be smooth and clean; for example, the wings must not have ice on them

no leaks; hydraulic fluid, oil, fuel, and other critical liquids should not be leaking out of the aircraft

chocks, control locks and covers removed; all chocks, protective coverings and locks should be removed before flight and stowed

correct tire inflation; wear on the tires should not be excessive and the tires should be inflated properly

fasteners present and correct; all bolts, shims, nuts and other fasteners should be present, undamaged, and correctly installed

hatches and fairings secure; removable inspection plates and any other small doors, fairings and cowlings should be in place and secure.

lights ok; the lights on the aircraft should operate correctly and their lenses should have no cracks or other defects

blades ok; the propeller or turbine blades (as the case may be) should be perfect with no cracks or chips

Overlooking any of these sorts of items can cause (and has caused) serious accidents or incidents in flight or during takeoff and landing.


The following is an (incomplete) list of checks carried out:

  • Engine - for any damage to blade (due to birdstrike etc.)

  • Tires - For any damage

  • Oil level indicator

  • Wings- Leading and trailing edges and tips for any damage

  • Any oil leaks

  • APU

  • Rear fuselage- tail skid area

  • Engine and fuselage- Any open cowling, exterior damage etc.

  • Probes- Any damage, ice etc.

  • Any other suspected damage.

  • In case of helicopters, condition of rotors for any damage.

A more detailed list can be seen elsewhere for B737 and A320.

  • $\begingroup$ One major item this list does not mention is fuel. Sumps, type, quantity. $\endgroup$
    – J W
    Commented Dec 30, 2015 at 2:29

The other answer gives what is checked, but doesn't really touch on the "why".

Here are a few examples:

Birgenair 301 - Crashed shortly after take-off because it is believed a pitot tube was blocked by a wasps nest.

Aeroperu 603 - Crashed shortly after take-off because some tape was covering the static ports left there because of maintenance work.

Gulfstream IV - Crashed during take-off because the gust locks were not deactivated (Gulfstream had some role to play in this because the gust lock system is supposed to limit throttle movement but was not operating properly).

Twin Otter crashed just after take-off because the control lock was still in place.

Medical Flight crashed after take-off when it was refueled with JET-A instead of 100LL.

As a pilot, there is little you can do in the air when something goes really wrong, but there is a lot you can do on the ground to make sure that the aircraft is worthy to fly. Preflight inspection is one step to a successful flight and preflight doesn't just happen on the tarmac walking around the plane, there are also safety checks that happen inside the cockpit (like verifying the controls are free) and even more before you even see the plane (checking weather, routes, destination airports, NOTAMs, etc).

  • 2
    $\begingroup$ +1 for refocusing on the question and the why. Related: Inadequate Preflight $\endgroup$
    – mins
    Commented Dec 30, 2015 at 12:48
  • $\begingroup$ A good article, thanks. $\endgroup$
    – Ron Beyer
    Commented Dec 30, 2015 at 14:04

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