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77 votes
Accepted

Why couldn't the A380 secure any orders for two straight years?

Several reasons: A380s are really expensive. Unit cost for an A380, depending on interior appointments, is about \$375 million. The 747-8 is about \$357 million. The 777-300ER is about \$320 million, ...
KeithS's user avatar
  • 22.6k
76 votes
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What is this hatch above the cockpit of a 747?

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 ...
Terry's user avatar
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58 votes
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Why does the second floor of the Boeing 747 occupy only part of the plane?

The basic design of the Boeing 747 was originally developed to for the US military's CX-HLS program for a large cargo aircraft. One of the main requirements of the program was for cargo to be loaded ...
fooot's user avatar
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55 votes
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Is this aerodynamic braking procedure normal in a 747?

This is not a recommended procedure for landing the 747 (or any other jet airliner I know of). The FCTM (Flight Crew Training Manual) says this: After main gear touchdown, initiate the landing roll ...
Bianfable's user avatar
  • 52.9k
47 votes
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Can the A380 ferry an extra engine, like the 747?

One of the main reasons the 747 was given the ability to ferry an engine was due to the lack of large cargo aircraft available at the time. Don't forget the 747 was a major game changer when it came ...
Gavin Coates's user avatar
  • 1,068
46 votes
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Was the Space Shuttle aerodynamically neutral while piggybacking, or did the combination act like a giant biplane?

This podcast with one of the pilots answers just about every question on the shuttle carrier you could have and it's worth a full listen. But to cover the flight dynamics, I would skip to 50:33 ...
Dave's user avatar
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45 votes
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Why doesn't GE replace all 4 engines for on their flying test bed instead of just 1?

They only change one, because that one is a new engine that is being tested. If you are testing a new engine you change 1 at first so if it fails you have 3 others. If you change all 4 and there is ...
casey's user avatar
  • 35.1k
39 votes

Was a six-engine 747 ever seriously considered by Boeing?

The "fifth engine mount" option on the 747 is not designed to handle a running engine. It was an option used only by Qantas as a means of ferrying spare engines to remote locations, where flying a ...
alephzero's user avatar
  • 3,010
38 votes
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Was the Boeing 747 designed to be supersonic?

No. The Boeing 747 was not designed for supersonic flight, though during testing, it was pushed quite close to the sonic speed: Tom Cole, a spokesman at Boeing Commercial Airplane Co., said original ...
aeroalias's user avatar
  • 99.6k
37 votes

What could explain the fact that during 1976-80, I used to hear commercial jets make sonic booms while flying overhead?

Note that 747's and other jumbo jets operating out of Bradley could not have produced sonic booms because they do not fly above the speed of sound (they only do 500 to 550 MPH at high altitude cruise) ...
niels nielsen's user avatar
36 votes

Why does the 747 have 4 engines instead of 2?

Simply, more engines = more power, and power is needed for several things, the first of which is, taking off. At max takeoff weight, a multi-engine aircraft has to be able to lose one engine (after ...
Ralph J's user avatar
  • 47.6k
36 votes

Are there any Boeing 747 still flying for commercial use?

Quite a few, actually. British Airways is the largest operator of B747-400 and flies a number of routes: Where does the Boeing 747-400 fly? The aircraft operates on a variety of routes, ...
aeroalias's user avatar
  • 99.6k
33 votes
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Is there any particular reason for the cockpit of the 747 being on the upper deck?

Boeing actually never expected the 747 to be so successful. They thought supersonic aircraft were the future. But Boeing knew that an aircraft the size of a 747 would be great for the cargo market. So ...
Ben's user avatar
  • 13.6k
33 votes
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What is ETOPS and how does it work?

ETOPS stands for Extended-range Twin-engine Operational Performance Standards, a rule which permits twin engine aircrafts to fly routes which, at some point, is more than 60 minutes flying time away ...
kevin's user avatar
  • 39.5k
33 votes
Accepted

Does a Boeing 747-830 exist and if it does, is there any difference to a 747-8 (748)

Until 2016 Boeing included customer codes into the aircraft model names. Your example 747-830 decodes as follows: 747: This is the general aircraft series. -8: The 747-8 variant (in this case, a 747-...
Bianfable's user avatar
  • 52.9k
30 votes
Accepted

What is the reasoning behind using depleted uranium as counterweights in the 747?

Boeing Boeing would have used DU because it had the right combination of physical characteristics and cost. Their tests showed that the radiation exposure for workers was low (2.6% of the statutory "...
RedGrittyBrick's user avatar
29 votes
Accepted

Is the entire length of a B747 or A380 wing used as a fuel tank?

Fuel tanks take most of the space in aircraft wings, but not all. There are other things on wings too. They are ailerons, flaps, slats, air brakes. On most airliners, the engines are attached to the ...
Farhan's user avatar
  • 29.3k
28 votes

Why couldn't the A380 secure any orders for two straight years?

It's not as fuel-efficient as a twin engine aircraft and doesn't offer as much scheduling flexibility. Comparing the 747 in 1969 to the A380 today isn't really a good comparison. A better comparison ...
reirab's user avatar
  • 19.2k
28 votes

Are there any Boeing 747 still flying for commercial use?

There are many airlines still operating the 747 in passenger service. Lufthansa has bought the 747-8, the last delivery was in April 2015, so I'd expect that the 747 will be in passenger service for ...
DeltaLima's user avatar
  • 78.1k
28 votes
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Are there any Boeing 747 still flying for commercial use?

There are still lots of 747's in scheduled passenger service and at least a few dozen of them will almost certainly remain so for the next 20+ years. 747-400 British Airways has 36 of them with ...
reirab's user avatar
  • 19.2k
28 votes
Accepted

What is this instrument for on the 747 flight engineer's panel?

It's for measuring the airplane's inclination on the ground for the longitudinal axis. There will be another one on a lateral bulkhead for measuring lateral inclination. When doing fuel quantity ...
John K's user avatar
  • 122k
26 votes

Would increasing the number of wheels of a Jumbo reduce the braking distance?

Typically, a little gain is obtained. Larger airplanes use anti-skid technology. Anti-skid works by modulating brake pressure to ensure the tires never skid. It's important to understand the relation ...
MrBrushy's user avatar
  • 758
26 votes
Accepted

Why do pilots cut the reverse thrust below 40 km/h?

The question speaks of a very old 747 landing tutorial. And as such I take that to mean it would be of a 747-100/200 aircraft, and that's the reference point I'm answering from. First, concerning the ...
Terry's user avatar
  • 39k
25 votes

Why does the 747 have 4 engines instead of 2?

In addition to what Ralph mentioned, up until the mid 1980s, regulations required that aircraft operating long over-water routes or other such routes with a lack of places to divert in the case of ...
reirab's user avatar
  • 19.2k
25 votes

How many kilowatts to get an electric 747-8 airborne?

First, let's figure out how much power a 747 needs to takeoff: Assume: Engine thrust = 284 kN Takeoff speed = 170 knots Takeoff power = 90% max power Using $P=Fv$, converting the variables to SI ...
kevin's user avatar
  • 39.5k

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