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76

It's an emergency escape hatch. There are inertial reels in the cockpit ceiling adjacent to the hatch to allow the cockpit crew to exit the airplane. See this link for an account of their use escaping the aircraft during a hijacking. There were five reels in the 747-100/200 aircraft. The cockpit had five seats: pilot, co-pilot, flight engineer, and two ...


46

These are rain gutters. They are designed to catch rain that runs off the upper surface of the aircraft fuselage and channel it away from the open aircraft door so that the water does not enter the cabin. This is a close up of the rain gutter over the main cabin door of a Beechcraft King Air B200, showing the channel that would catch and redirect water ...


31

The crew has already secured the door just before leaving the gate, cross-checked them and the pilots saw the sensors indicate closed. So if the warning goes off during take-off roll, it is not somebody's simple mistake, but something is broken. It might be the sensor, but it might be something on the door and that might be pretty bad. So as the old saying ...


27

The crew of Rockwell B-1 Lancer (4 in total) enter or exit the cockpit from the underside, using a ladder. It can be seen in this video. This picture shows the ladder (the one on the right): Image Source On the top of the ladder, there is a door, which looks like this: Image Source


19

This picture shows a ladder behind the front landing gear. Image Source


18

Yes if prior to V1 (takeoff decision speed). On most modern airliners there are proximity sensors that monitor the latching system at various points, that will produce various warning or advisory messages (for example, a single sensor out of an array of several on a given door may provide only an advisory, whereas more than one sensor agreeing may produce a ...


14

It's for the passengers on a rainy day. If this strip would not be diverting the rainwater flowing from the upper fuselage, a curtain of water would soak the passengers upon entering or leaving the aircraft, and the cabin floor.


12

Having one door is just a design preference which makes the aircraft simpler, and lighter to build. There are many other light aircraft with only one door. Besides Piper, most Mooney, Beechcraft, and Bellanca aircraft only have one door. Even the high wing Cessna 195, 206, P210, 337, and low wing Cessna 310 and 340 have only one door.


12

There is a hatch and a ladder in the bottom of the front fuselage, through which the pilots enter the bomber, as seen here:


12

It contains the evacuation slide. From airspacemag: An escape slide sits inside a carbon fiber pressure cap covered by a casing of material similar to the aircraft interior walls—that big square box at the bottom of an airliner’s interior door. Here's an image from Boeing: Image from Boeing.com According to Boeing, the positioning of evacuation slides ...


10

A door that is, say, 36" x 80" (0.9m x 2m), with a surface area of 2880 sq/in (1.8m2), at 8 psi (55kPa) max cabin pressure differential, which most airliners run at, will have roughly 12 tons (102kN) acting on the perimeter fittings trying to blow it out. Any other forces acting on it are microscopic in comparison. For non plug type doors that depend on ...


9

Normally there is some kind of barrier, a bulkhead or curtain, separating the business class and the common folk in steerage. In such a case the sign is to indicate that there is an exit somewhere down yonder beyond the bulkhead. In this case the curtain is not there so the sign kind of hangs there with its nonsensical implication that maybe there is an ...


8

The only one I can think of is the Junkers F13. It has an open cockpit and an enclosed 6 passenger cabin. There's no access between the two areas; only a small window. Credit:THOMAS LÜTHI / RIMOWA 2016 The CEO of Remowa is having recreations made of the aircraft which first flew in 1919. It was (according to Rimowa) the world’s first all-metal commercial ...


8

Aircraft have a maximum gear extension speed (V$_{LO}$, as in maximum landing gear operating speed), which is normally 1.6 times stall speed, so when the doors move, the dynamic pressure is rather low. Therefore, the forces during gear extension are not the only ones to check. In cruise, suction on the gear doors might be the limiting factor for both ...


7

Most of the airline doors are plug type- i.e. they are wedge shaped, so that the pressure differential pushes it against the fuselage and prevents opening. For example, the following image shows the Boeing 737 door. Image from airteamimages.com Note that the door is bigger on the inside, so that when it is locked in position, the pressure will push it ...


7

The McDonnell Douglas DC-10 and Lockheed L-1011 are wide body "heavy" aircraft with all door exits, no overwing window exits. Mid fuselage doors were built into these aircraft to provide multiple points of entry and exit to speed up normal passenger boarding and deplaning, not specifically for emergency exit efficiency. Positioning them near mid-fuselage ...


7

(Image source) The reason is the fillets (wing root fairings). They're curved as shown above. You could have a plane without those fillets, but then there are two downsides: Considerable increase in fuel consumption, and thus reduced range Potential extra strengthening required for the fuselage/wing connections, as a direct floor-to-wing-top exit might ...


7

The major difference is size. FAR part 25.801 defines them as: (1) Type I. This type is a floor-level exit with a rectangular opening of not less than 24 inches wide by 48 inches high, with corner radii not greater than eight inches. (2) Type II. This type is a rectangular opening of not less than 20 inches wide by 44 inches high, with corner ...


7

Testing the doors (and windows) by pressurizing the cabin eats into the aircraft's pressurization cycles. Instead vacuum is used to simulate the in-flight conditions. A special fabric and a sheet with attachments to hoses are attached to the outside where the door/windows are to be tested. Vacuum is created between the fabric and fuselage, thereby locally ...


6

The flight deck door lock system is normally turned on while on the ground and remains on for the entire flight. Once the system is turned on, the door DOES lock automatically when closed and can only be opened by the pilots in the flight deck. If both pilots left the flight deck, the door would lock automatically behind them unless the door lock system ...


6

The Cessna 150 Aerobat and 152 Aerobat both have jettisonable doors. I don’t believe any version of the Cessna 172 does as there in no aerobatic C172 versions. This Photo shows two “D” rings which are pulled to jettison the doors.


5

The larger port side doors are for extra convienience during boarding. Passenger boarding is always done on the port side (left) while the starboard side doors are only used for servicing the galleys or as an emergency exit.


5

From the EMB120 Ops Manual: FORWARD ENTRY DOOR The forward entry door incorporates a folding air stairs and is fixed at the fuselage's lower edge. The door can be raised manually or hydraulically. For normal operation, two hydraulic actuators powered by the green hydraulic system or by an accumulator, raise the door. This actuator ...


4

Some DH.83 Fox Moth had an enclosed cockpit (not all, some had open cockpits). Several examples are still flying, including one in Ottawa. It has a cabin for three passengers with an entry door, and behind and above that a cockpit with (in some aircraft) a sliding glass canopy Flying example from Vintage Wings of Canada Wikipedia page


4

If you are talking about passenger doors, their surface will be mostly parallel to the direction of motion, so the wind will not act directly on them (otherwise the aircraft would be in a sideslip, with the drag and fuel consumption greatly increased). So yes, you can assume only the external pressure is acting on them (plus gravity). The pressure will ...


4

It reduces weight and increases the structural strength of the fuselage, particularly with the typical design of a low wing aircraft. Later low wing aircraft like the Cirrus make use of an internal crash rollcage in the dorsal spins of the fuselage which adds extra strength to accommodate the second door. Diamond uses a semi monocoque tub-like design with ...


4

Outward swinging doors require a great deal of effort to open and close, and can require the operator to potentially lean outside of the aircraft and risk a fall to close. The 757 door originally had an issue where shorter operators could not get enough leverage to open (see: Making It Fly in the Seattle Times. Upward doors were used for a while but they ...


3

Piper's early low wing plane history, the best info I have found has been this: http://www.pilotfriend.com/aircraft%20performance/Piper/11.htm In 1954, Bill Piper was looking for a design to compete with the Bonanza. The engineers at Piper were busy with other projects at the time, so Bill Piper asked his friend Al Mooney if Piper could buy the new ...


3

Pressurized aircraft often leak like sieves once they get older. It's difficult to set limits unless an OEM provides a specific procedure, and an OEM procedure may be designed for new a/c as a quality control measure without any latitude for service deterioration. There isn't really any guidance on leak rates in the FARs for cert purposes. There is only ...


3

Okay, I may have found one; the Bristol Wayfarer (a passenger version of the Bristol Freighter) had a passenger cabin in the main fuselage, with an enclosed cockpit perched on top. The aircraft's arrangement makes me suspect that the cockpit was isolated from the main passenger cabin, but I can't confirm yet whether or not that was actually the case. As @...


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