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Questions tagged [feature-identification]

For questions about identifying a feature or design on an aircraft.

218
votes
4answers
139k views

What is the dark spot visible below the cockpit on A-10s?

On most A-10s I have seen, the area under the cockpit is darker than the rest of the plane. Is there a reason for this?
55
votes
3answers
17k views

What are these things hanging off the trailing edge of the wing?

What are these things hanging off the trailing edge of the wing? I've seen them in almost all of the aircraft I've flown in, and can't remember if they're exclusively Boeing or Airbus.
44
votes
1answer
11k views

What is this hatch above the cockpit of a 747?

There is a little door on the upper deck above the cockpit: Source: Airliners.net, (modified to indicate location of hatch). What is that door? What is its purpose?
43
votes
4answers
10k views

What is this hole at the front of the engine pylon on a Boeing 707?

Images of the Boeing 707 show a hole at the front of the engine pylon just above the engine. Can someone please tell me what is the purpose? Also why do images show the hole absent on the left outer ...
43
votes
1answer
6k views

What does this plus (cross) sign on this electrical panel mean?

I'm looking at a picture of the electrical panel of a Phenom 100 and on it I see a + sign, does anyone have any ideas as to what it's supposed to mean?
40
votes
1answer
2k views

Can experts identify the model using this part (FOD prevention purposes)?

We found this part of an aircraft recently and, in order to improve the safety levels at our airport, we would like to know what possible aircraft model (or models) are compatible with this cover so ...
38
votes
2answers
6k views

What are these five indicators at the front of the 737 passenger cabin?

As a passenger I noticed set of five indicators on ceiling at the front of the 737 passenger cabin. They are: red, yellow (or white), blue, white, red. Red ones seem to be coupled together (what ...
29
votes
2answers
15k views

What is this on top of the Air Force One?

Clarification: It wasn't Air Force One that visited Switzerland, it was the 747-200 E4 carrying Ashton Carter. Source What is this thing on top of the plane (In red circle): On other "Air Force One" ...
29
votes
2answers
3k views

What are these boxes built into the tails of some fighters?

In looking at European-designed fighters of the 4th and 4.5th generation, I keep seeing a common design feature; a box-like structure built into the tail, often in the top half or third. Some examples:...
28
votes
2answers
4k views

What are those hatches on the engines of a B-2 that are open during takeoff?

I just watched this drool-inducing video of Northrop Grumman B-2 Spirit, And noticed that there are a couple of hatches near each engine, which were open: I initially thought they were open for some ...
28
votes
1answer
2k views

What does this black triangle placard on board an A320 denote?

Just out of interest whilst travelling aboard a British Airways A320-232 G-MIDT on the 9.45 BA shuttle service (LGW-GLA) in seat 10F I noticed a placard above the window of seat 9F. Given this seat ...
27
votes
2answers
5k views

What is that device on an Su-27 pilot's helmet?

While watching a YouTube video (2.5hrs), I noticed this device on the top of most Russian Su-27 combat pilot's helmet. A google search only shows it for a Su-27 and MiG-29, but apparently no other ...
27
votes
1answer
4k views

What is this pattern on the A350 front window?

The image is extracted from this video (at 3m40s, when taking off) I circled in purple the strange pattern formed by few black straight lines. I'm quite puzzled as I have no idea of what it is or ...
27
votes
1answer
23k views

Why is there a hole in one of the layer of an airplane's windows?

On a commercial airliner, there is a hole in one of the layer of the passenger windows. See here: and here: Or in more detail: Can you explain the physical reasons for this design choice?
25
votes
5answers
4k views

What is this F-18 Hornet “air intake” for?

I think I read once that they served to cool the on-board computer systems, but I'm not sure.
21
votes
2answers
5k views

What is this 'ball' in front of the cockpit of some fighters, e.g., an Su-57?

What is the lump/ball thing visible below and to the left of the canopy in this image of a PAK FA (which became the Sukhoi Su-57), and what is it for? It's also seen on other fighters. Image source
21
votes
1answer
1k views

What is this device they bring on board from the jet bridge when we park?

Every time I deplane a Virgin America A320, I notice that they grab something from the jet bridge, and stuff it between the jump seats. I haven't seen any other commercial airlines with things like ...
21
votes
1answer
973 views

Why did some Caravelles have a very long dorsal fin?

(Source) Why did some Sud Aviation Caravelles have a very long dorsal fin stretching half the fuselage? Initially I thought it's to keep the fin low to fit in existing hangars as a selling point, ...
20
votes
1answer
6k views

What are these “pimples” on the jet engine for?

When looking into the General Electric CJ 805-23B jet engine, I have discovered that all forward section of the compressor is covered by a number of near identically looking "pimples". What are these ...
19
votes
2answers
4k views

What are those arrow markings on the wing?

I recently flew on a Boeing 737-800 and found these arrow markings on the wing. What are they for?
18
votes
2answers
5k views

What's this hole on the ATR-72?

There is a hole on the belly fairing circled in yellow. I guess is an air intake but I tried searching some info and couldn't find anything. Source
18
votes
2answers
3k views

What is this cutout in the Spitfire cockpit glass?

This is a still from the film Dunkirk. I realise this is not a historical document, but I have also found a similar feature in photos of real Spitfires. What is the purpose of this?
18
votes
2answers
2k views

What's the function of the plate behind the wheels of the Pilatus Porter?

Anyone knows what's the plate behind the wheel of the Pilatus Porter for?
15
votes
2answers
5k views

What exactly are those openings in the bellies of many jetliners?

I have circled the areas (in yellow) under the belly of the 737. What exactly are those? (airliners.net)
15
votes
2answers
778 views

What is this nose cowl mounted display?

(YouTube) A crop duster's nose mounted display. It looks like a poor man's HUD to keep the display and the outside view at roughly the same focus distance, but what is its function?
15
votes
1answer
2k views

What is this pipe on the tail of this helicopter?

In this picture of a CH-53 you can see a pipe or rail on the tail section of the aircraft. What is that?
15
votes
1answer
2k views

What is this device protruding from the rear of this 787?

While looking at the photos from this question I noticed a small protrusion from the side of the plane. You can see it in the photo: and in the diagram from l@aeroalias answer: In the diagram it ...
14
votes
1answer
992 views

What are those things on the B747 engine pylons?

I noticed some dots and lines on the Boeing 747 engine pylons. What are they? The above image is as seen in this video at 2:18.
13
votes
2answers
1k views

What engine are these fan blades from?

I bought these from a metal scrapper and paid about $30.00 total figuring they're worth more than that in cool factor. Problem is they aren't nearly as cool if I can't figure out what engine (and ...
13
votes
1answer
912 views

What are the circles/holes ahead of the wing of an MD-82?

In the picture below I noticed there are three circles or holes of some kind ahead of the wing, what are those? (airliners.net)
13
votes
2answers
2k views

What is this thing between the engines on the F-14 Tomcat?

On the F-14 as you can see from a picture there is some exhaust like thing in between engines. What is this?
12
votes
4answers
3k views

What is this ring-shaped device behind this DC-8's jet engine?

What is this ring-shaped device behind this Douglas DC-8's jet engine? (YouTube)
12
votes
1answer
2k views

What is this red dashed line between door and cockpit window?

I noticed this dashed line located between the door and cockpit window on this 737-300 while boarding this exact aircraft at Ibiza airport. It seems to have text beside it but I did not have time to ...
12
votes
1answer
573 views

What is this “Micro T-tail” on the F-102?

I just noticed this unusual thing on the F-102 Delta Dagger. It looks like a micro T-tail. What is it actually, and what is its purpose?
11
votes
2answers
3k views

What is this on the starboard engine of the Dash 8?

On the inside of the starboard engine of the Bombardier Dash 8 Q400 there is a small aerofoil shaped object* protruding from the casing. There also appears to be pipes protruding from the end of it. ...
11
votes
1answer
737 views

What is this object on an MD-11?

There is something above the engine on the tail of this MD-11: What is that? Source
10
votes
1answer
798 views

What is the metal plating on the back of the A-6 for?

What is the perforated metal plating on the back of the A-6/EA-6 for? Source: Wikipedia
10
votes
1answer
687 views

What are those things under the Concorde’s cockpit windows?

I’ve noticed there are little bits sticking out under Concorde’s cockpit windows and they’re too small to be canards. Are they some kind of vortex generator or something? (Source)
9
votes
1answer
1k views

Why do the A220 cockpit seats have a cutout?

Why do cockpit seats on the A220 have a cutout on the bottom cushion? The answers to Aircraft pilot's seats: what is the notch for? explain that these cutouts allow for easier maneuverability of the ...
9
votes
2answers
2k views

What are these grilles in the passenger cabin of this 787?

Below the windows, ahead of the seat, there are small grilles. Look: Source: Airliners.net What are those for?
9
votes
1answer
395 views

What is this fuselage-side aerial used for?

(instagram.com) I have seen this picture, and this feature on the port fuselage called my attention. Does anybody know the purpose of this?
9
votes
1answer
990 views

What are these parts on STOL/bush planes?

I've seen these (note the parts pointed to by the red arrows in the image) on the landing gear struts of Super Cubs and plenty of other STOL bush planes with large tundra tires. It looks like maybe ...
8
votes
2answers
1k views

What is this feature on a Sukhoi Su-27? [duplicate]

Most but not all Russian Su-27's (and variants like the Su-30, -32, -33) have a device that looks like a headlight in front of the cockpit. What is it?
8
votes
1answer
2k views

What is the function of this fixed protrusion on the tail?

(wikimedia.org) Above you can see a small fixed (?) part on the Embraer 190, just above the KLM logo. It is on both sides of the tail. What is the function of this part?
8
votes
1answer
2k views

What is the function of the protruding outlet on the Trent XWB?

Original by Bernd Sieker from Germany (Trent XWB) [CC BY-SA 2.0], via Wikimedia Commons Above is a photo of the Rolls-Royce Trent XWB highlighting the aft facing outlet in question. In a video for ...
8
votes
1answer
1k views

What is this display on the 737 Classic?

Source: YouTube I noticed that display (yellow circle) between the two CDUs. What is it for? It is not a default installation on the 737-3/4/500. It looks like a Navigation Display/MFD, but why have ...
8
votes
1answer
308 views

What additional functionality is provided by the F-14 nose pitot, absent in early models?

Early model F-14A had no nose pitot: ... but they seem to have quickly acquired them sometime in the late 1970s. The Iranian F-14s have them, and it's quite hard to find a picture of an F-14 without ...
8
votes
1answer
1k views

What is the purpose of this helicopter fin antenna?

I'm an airplane guy, but I've got a quick helicopter question. I've seen a few helicopters with what seems to be a fin shaped antenna on the middle of the fuselage just above the windshield. I've also ...
7
votes
2answers
998 views

What is that missing instrument on a Beechcraft 1900C?

(Full image) Beechcraft 1900C. I cannot find the name of the missing instrument even in the manuals.
7
votes
1answer
246 views

What are those sensors on the forward (Airbus) A321neo fuselage?

What are those sensors on the forward (Airbus) A321Neo fuselage? If it helps, this is wow air’s TF-DTR.