In the flight manual (DA-20) in the wing section it is written: “Aileron including inspection panel - visual inspection”. What does the “including inspection panel” part mean?

Also, during In-Cabin check when it’s written e.g. “Free” in relation to different knobs. What is expected exactly? E.g. I see “Carburetor Heat” - “free, OFF” as I have to check if the relevant knob is just pulling in/out freely and leave it in OFF position. But if it’s written just “Free”?

  • 3
    $\begingroup$ Seems to me to be 2 different questions here. Just because they're both part of the pre-flight inspection doesn't mean they're related. If you'll take the tour, you'll see that the Q&A model here requires one question per post, or two very closely related ones. Please edit this down to one question, then ask the other in a separate post. Nobody will look down on you for doing so. $\endgroup$
    – FreeMan
    Commented Jan 12, 2022 at 17:14

2 Answers 2


"including inspection panel" means that when inspecting the wings you should also access any inspection panels - looking up an online manual for the DA20 describes thusly:

The bottom shell of both wings has holes for access panels below the flap and aileron bellcranks. The bottom shell has a hole for an access panel below the B-bolt. This gives access to the B-bolt for removing the wings.

Which means you should probably open any inspection panels which are accessible without tools (ie, a screwdriver) and check the general condition of any parts inside, such as structural spars, linkages, bolts etc.


The term "Free" in a checklist against anything such as a knob or lever means that that lever is not impeded from movement in any way and can travel the full range of expected movement. For example, that there is not a control lock in place, or something in the way of its movement or that any bearing have not seized it in place.

The ones which say "Free, OFF" probably have a reason for doing so, the ones that say just "Free" probably sets them in a latter step to something sensible. eg, "Trimmer: Free" - later on pre-takeoff it will say "Trimmer: Set take-off". Contrast to "Mixture: Free, ICO" - its important that mixture is reset to Idle Cut Off after the check for "free"

  • $\begingroup$ Thank you, Jamiec. So if it’s “Free” I can check the knob and put it in OFF position? Because I found interesting that for some knobs it’s said exactly “free, OFF” and for some just “free”. I thought that probably I’m free to select required position but for this stuff there is written specifically “as required”. Also thank you for online manual link. $\endgroup$
    – Sergey
    Commented Jan 12, 2022 at 14:07
  • $\begingroup$ Updated answer with more detail @Sergey $\endgroup$
    – Jamiec
    Commented Jan 12, 2022 at 14:43
  • $\begingroup$ Just to reiterate, @Sergey, "Free" here means "free to move," that is "unrestricted in any way." Very bad things can happen when controls are restricted. $\endgroup$
    – randomhead
    Commented Jan 12, 2022 at 15:38

Inspection panels on the wings are usually fastened with screws, ie. they're not meant to be accessed without tools. That is the case on the aircraft I fly, and inspecting them means checking that all panels are in place and secure, ie. you won't end up flying with a big hole on the bottom of your wing.

The ones meant to be accessed without tools and opened during preflight should be specifically called out and described as such in the POH. Indeed, whilst the maintenance manual on page 47 states:

The DA20-C1 aircraft has a small number of access panels. The panels give access for maintenance. Most panels are GFRP moldings. Self-tapping screws or camlock (quick-release) fasteners hold the panels.

the POH does not mention them other than by "visual inspection". This means you're not supposed to access the panels during the preflight, merely look at them and confirm they're there, intact and secured properly.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .