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36 votes
Accepted

What are these 4 red spots on the A-10?

I am fairly sure that these are the fuel hatches. They are placed right over the wing and main fuselage fuel tanks. (The hatches are where the fuel is put into the craft, not drawn out for sampling). ...
Nicholas's user avatar
  • 668
33 votes
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What is the purpose of the black and white stickers on test aircraft?

They appear to be fiducial markers which identify known points on the aircraft, for analysing video footage and performing photogrammetry. You see similar markers on crash-test dummies used in vehicle ...
Toby Speight's user avatar
  • 1,109
18 votes
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Why does this Curtiss Kittyhawk have a Question Mark in its squadron code?

It was fairly common to use “?” if there were more than 26 aircraft in the squadron. (only 26 letters in the alphabet) Camouflage and markings of No.112 Squadron RAF, “The second thing is the use of ...
Mike Sowsun's user avatar
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16 votes
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Are the size and location of the registration number regulated?

Under FAA jurisdiction, these items are regulated under 14 CFR 45. The size of the registration markings must generally be at least 12 inches high: §45.29 (a) Except as provided in paragraph (...
J W's user avatar
  • 16.6k
12 votes

What is the meaning of the letters on the side(s) of WWII British aircraft?

Spitfires had a few different markings, but primarily there were two. One, written in smaller, often black, text was the aircraft serial number and stayed with it for its entire life. The other, ...
Jamiec's user avatar
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10 votes
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What is the yellow marking underneath Delta A220 doors?

This is almost certainly an alignment marking for the passenger boarding bridge (jetway). You can find the same markings on other Delta aircraft as well: (image sources: A320, B737, B767) The dead ...
Bianfable's user avatar
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8 votes
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Why paint a British roundel on a non-British Lynx?

Best guess; the photos are from the delivery flights in the 90s. The helicopter in the photo has the same registration as when it was first delivered (ZH583) and has not been active since. Update: ...
bjelleklang's user avatar
  • 4,165
8 votes
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What does this logo on prototype aircrafts or cars for test mean?

This is simply no logo, but a reference that is both highly visible and can be measured very precisely in photos and videos - this giving a valid reference point for all measurements and analysis.
tsg's user avatar
  • 2,770
8 votes

Checkerboard painted on fuselage of Boeing test aircraft

the checkerboard mark allows accurate indication of the position of the plane using cameras as the plane flies by. by tracking the movement of the checkerboards between frames of a series of camera ...
niels nielsen's user avatar
7 votes
Accepted

What are these markings under the passenger door?

They appear to be alignment marks for the passenger loading bridge (PLB) and air stairs. Some airlines choose mark their aircraft and bridges, in order to prevent damage to the aircraft door due to ...
newmanth's user avatar
  • 5,177
6 votes
Accepted

Why is this Cessna flap position indicator marked so irregularly?

Because it was the analog world and no other (easy) solutions exist. Providing an exhaustive answer will require too much space here, but I'll give the idea with the help of some figures. So, this is ...
ocirocir's user avatar
  • 2,683
4 votes

Why is the angle of the horizontal stabilizer marked on the fuselage?

I don't have the reference but it's showing the trim setting. The picture looks like is an Embraer 170 on which the entire horizontal stabilizer moves. The gauge gives a quick visual setting to ...
JWilde's user avatar
  • 61
3 votes

Why did the F-4 Phantom have quite so many stencilled messages?

I assume you know they’re an aid in locating access panels, exterior switches, etc. for maintainers, feelers, etc. and are instead asking why the F-4 feature them more than models of other type. So, I’...
Nick Dazzle's user avatar
3 votes

Why is the angle of the horizontal stabilizer marked on the fuselage?

The markers are for the ground crew member to report to the flight crew the actual position of the stabilizer trim, which the flight crew checks against the cockpit reading. This is just to ensure ...
Saxon Xander's user avatar
2 votes

What are the degree markers on the tail of this MD-10 for?

This tells the maintenance mechanics what trim state the elevator is in without having to run the pitch trim motor back and forth from the cockpit.
niels nielsen's user avatar
2 votes

What is the yellow marking underneath Delta A220 doors?

I'm just guessing, but it could be a guide for positioning the steps, especially as ground crews are still getting familiar with A220.
RunawayPilot's user avatar
2 votes

What are these 4 red spots on the A-10?

Nicholas got the geist of this one. The red circles are marking on the four gravity fill fuel tank ports. The A-10 also uses a pressure fueling port is located on the port landing gear fairing ...
Romeo_4808N's user avatar
  • 74.3k

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