Questions tagged [boeing-747]

A medium- to long-range four-engine wide-body jetliner (the original "Jumbo Jet") introduced into commercial service in 1970, easily recognizable by its distinctive hump forward of the wings. Different versions typically seat between 266 and 660 passengers.

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Why does the US President fly in an obsolete 747-200?

The Boeing VC-25A ("Air Force One") is a heavily modified 747-200. The two current airframes (SAM 28000 and 29000) were put into duty in 1990 and are slated to be replaced in 2017, although I suspect ...
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Can the A380 ferry an extra engine, like the 747?

A useful little quirk about the 747 is that it can ferry a fifth engine on the wing, for when another aircraft is stranded somewhere in the world. Does the A380 have the same capability? If not, how ...
Ben's user avatar
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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?
user13197's user avatar
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Was the Space Shuttle aerodynamically neutral while piggybacking, or did the combination act like a giant biplane?

Trying to investigate this question, I see that 'Ask the Captain' says: The weight of the shuttle is calculated like any payload. The 747 produces enough lift to fly and to carry the weight of ...
Party Ark's user avatar
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39 votes
8 answers
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Why couldn't the A380 secure any orders for two straight years?

The double-decker aircraft has failed to win a single order from any new airline customer for two years now. Comparing its orders and sales with its biggest competitor, the B747 it had received 315 ...
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39 votes
2 answers
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Why don't El Al 747's stay at the gates at JFK?

I was recently travelling through JFK in New York City and saw the El Al 747, presumably arrived as ELY1 and departing as ELY4, sitting on the apron near terminal 4. What I saw was similar to as shown ...
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37 votes
3 answers
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Why does the second floor of the Boeing 747 occupy only part of the plane?

Why does the second floor of the Boeing 747 occupy only part of the plane, while the second floor of the Airbus a380 occupies the entire space of the plane?
JeanExtreme002's user avatar
33 votes
5 answers
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What is ETOPS and how does it work?

According to this press release by Boeing earlier this year, the 747-8 has received its ETOPS 330 rating. This is required by all 4-engined planes made after February 2015 to fly beyond 180 minutes ...
collector's user avatar
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32 votes
6 answers
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Are there any Boeing 747 still flying for commercial use?

No American airline flies it anymore, but the Jumbo has been mythic for decades: ANA B747-400. Wikimedia, photo by Kentaro Iemoto Is it still possible for a passenger to board a Jumbo Jet? Which ...
mins's user avatar
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30 votes
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Why don't B747s start takeoffs with full throttle?

Why does the 747 start takeoff with partial power and increase to full throttle later down the runway, when the A380 for example starts on full? Source This is not the same question as: Is it ...
jwzumwalt's user avatar
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Why does the 747 have 4 engines instead of 2?

If the 747 can fly with two engines, why does it have four engines? What is gained by adding another 2 engines? Flights over the ocean? Fuel savings? Safety?
goln's user avatar
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29 votes
2 answers
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Where does Air Force One refuel?

Obama came to Greece and then to Germany. That's a long trip, even for the majestic Jumbo. There was a lot of discussion about where the aircraft was refuelled during that trip. Do we know, in general,...
gsamaras's user avatar
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27 votes
4 answers
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What is the maximum safe bank angle of a 747?

This question arose during the comments of another question, linked for the curious: What does it take to turn a 747 around 180 degrees? Because the discussion was interesting, (and to avoid ...
Bassinator's user avatar
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26 votes
4 answers
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What is the reasoning behind using depleted uranium as counterweights in the 747?

I recently found out that some of the earlier models of 747 had between 600 and 1100lbs of depleted uranium as counterweights. These counterweights were found in 747s manufactured between 1968 and ...
Ron Beyer's user avatar
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25 votes
7 answers
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How many kilowatts to get an electric 747-8 airborne?

Reading about the Airbus E-Fan and it's dual 30 kW thrust fans caused me to wonder: assuming the need for four electric fans, how many kilowatts would be required to power each fan with enough thrust ...
Mike C.'s user avatar
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24 votes
6 answers
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Would increasing the number of wheels of a Jumbo reduce the braking distance?

If weight was not an issue, would increasing the number of main gear wheels on a jumbo such as the Airbus A380 from 20 to 40 wheels, each equipped with braking disks and braking equipment, considering ...
securitydude5's user avatar
23 votes
2 answers
6k views

Is this aerodynamic braking procedure normal in a 747?

I found this instagram video via YouTube: The description in the YouTube video states that: This aerodynamic baking procedure is applied to reduce wheel brake and engine wear I have two questions: ...
nodapic's user avatar
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22 votes
6 answers
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What is the minimum stopping distance for a 747-400?

Im looking at purchasing disused 747-400: The aircraft will be stripped of all seats and other non essential items. The aircraft will be then flown to my property in Victoria, Australia and perform ...
Cuban8's user avatar
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22 votes
3 answers
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What happens when disengaging the electricity generators on a B747?

This answer says: If let's say, you [...] disengage the electricity generator of every engine (which cannot be re-engaged without mechanical maintenance), [...]. What exactly happens in the ...
Noah Krasser's user avatar
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21 votes
3 answers
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Why do certain aircraft's landing gear tilt up?

Why do the main landing gears of aircraft like the A330, 777, 787, etc tilt up? This does not happen with the 767. Interestingly, for the 747, the inner landing gear does not tilt up while the outer ...
Madhav Sudarshan's user avatar
19 votes
3 answers
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In a 747 is it normal for the Vr (takeoff speed) to vary greatly depending on fuel load and ambient temperature?

I was reading one of the documents linked on this question, particularly I was reading case study number 8 of this particular document. In the conclusion the author notes that the aircraft flight ...
Jae Carr's user avatar
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Is there any particular reason for the cockpit of the 747 being on the upper deck?

The cockpit of the 747 is on the upper deck, but the cockpit of the A380 is situated on the lower deck. Is there any reason (be it engineering or anything else) for the location of the cockpit?
Madhav Sudarshan's user avatar
19 votes
1 answer
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What is the upper deck on converted freighter long-hump 747s used for?

All 747s1 have an upper deck directly behind the elevated cockpit, a legacy of the 747’s genesis as a design for a strategic-airlifter competition (the upper deck and elevated cockpit were partly to ...
Vikki's user avatar
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19 votes
2 answers
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Why do the 747's wing gear tilt while airborne, but not its body gear?

The 747's sixteen main-landing-gear wheels are distributed over four bogies: two four-wheel wing gear, mounted underneath the inboard wings, and two four-wheel body gear, mounted under the fuselage ...
Vikki's user avatar
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18 votes
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Does Air Force One (VC-25) have retractable staircases on all its exit doors?

While going through an article on AFO, I came across this little piece of info: So, does it have retractable steps on all its exit doors? How does it manage doors like these?
Firee's user avatar
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18 votes
1 answer
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What are these silver stripes on Cosmic Girl for?

Cosmic Girl (a 747-400 used for launching things into space)1 has a network of silver-coloured stripes on its empennage, starting at the (closed-off) last cabin window, and going aftward and upward ...
Vikki's user avatar
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18 votes
1 answer
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Why is the Boeing 747-300 not in service anymore?

Doing a little doodling on flightradar24.com and Wikipedia, I saw that all the versions on the Boeing 747 except for the -300 version are used. Why is the Boeing 747-300 not used even though it is ...
SMS von der Tann's user avatar
17 votes
4 answers
10k views

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

The Boeing 747 can carry a fifth engine on the side. As the airframe looks quite symmetric, I think that it would not be big work to hang a sixth engine on the side as well. From here, we seem to be ...
h22's user avatar
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17 votes
2 answers
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Why did early 747s have only two or three windows on the upper deck on each side?

All 747-100s and some 747-200s were built with just three windows on each side of the upper deck.[1] I'm wondering why so few? Some of the 100s were retro-fitted with ten windows on each side, so ...
Party Ark's user avatar
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16 votes
1 answer
3k views

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

Above the flight engineer's panel in a 747-100 there is an instrument that looks like a curved spirit level. What was it used for? source
Party Ark's user avatar
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16 votes
2 answers
3k views

Why were the 747SP's trailing-edge flaps so much different than those of the -100/-200?

I read several decades ago about how the 747SP's trailing edge flaps were substantially redesigned from those of the "original" 747-100/-200s. The images on the 747SP Wikipedia page clearly show what ...
pr1268's user avatar
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15 votes
6 answers
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What is the difference between a tire deflation and a tire explosion?

In this question, our intrepid former 747 pilot Terry mentioned, in the accepted answer, that: As I understand it, tires that dangerously overheat will explode before melting, and that's why ...
FreeMan's user avatar
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15 votes
3 answers
5k views

Why doesn't GE replace all 4 engines for on their flying test bed instead of just 1?

GE (General Electric) flies Boeing 747s equipped with new engines that are being tested. Why can't they equip the test airplane with all 4 of the new engines? Wouldn't the thrust be imbalanced by ...
Ethan's user avatar
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15 votes
2 answers
4k views

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

Two years ago I've uploaded a video of the Lufthansas Boeing 747 "D-ABYA" to Youtube. I am currently receiving some angry comments on that video because the title reads "747-830 with ...
Marv's user avatar
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15 votes
4 answers
20k views

Is it possible to use reverse thrust while airborne? [duplicate]

I play a flight-sim called X Plane. The other day while I was approaching an airport a little too fast and knew I couldn't slow down in time. I decided to use the reverse thrust while I was still in ...
jay_t55's user avatar
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15 votes
6 answers
22k views

Why is C-5 Galaxy not used for commercial airlines while Boeng 747 is?

For a layman like I am, both the planes look massive and similar in size and shape, as if a near copy of each other. Do the similarity only end in the size and shape? Do they not perform equally well ...
the_naive's user avatar
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2 answers
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Is the entire length of a B747 or A380 wing used as a fuel tank?

It is generally understood that the fuel tanks of aircraft are in the wings, but specifically, is the entire length of the the wing of: an Airbus A380 Jumbo used as fuel tank? a Boeing 747-800 Jumbo ...
securitydude5's user avatar
15 votes
2 answers
4k views

Why keep the doors open for aircraft in boneyards?

Photo by Bastian Ding from airliners.net The image above shows Boeing 747s stored in a boneyard. Why are the aircraft left with the doors open? Won't this increase the probability of further ...
vasin1987's user avatar
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14 votes
5 answers
11k views

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

I've read on this site & on Wikipedia that there have only been a couple of commercial jet planes in history that have broken the sound barrier--either in testing (without passengers) or during an ...
Carrie Morse's user avatar
14 votes
4 answers
11k views

Was the Boeing 747 designed to be supersonic?

I heard a rumour that the Boeing 747 was originally designed for supersonic cruising. Is this correct? Are the airframe and wings able to cross the sound barrier without damage?
Dániel Kis's user avatar
14 votes
3 answers
13k views

Is there an aircrew bunk in the 747 cockpit?

Reading this article, I came across the quote : Pilots also enjoy its creature comforts: at BA the 747s are known as the ensuite fleet. “Our little bedroom is within the cockpit: you can stick ...
glaucon's user avatar
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14 votes
1 answer
2k 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.
XF-91's user avatar
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13 votes
2 answers
11k views

Can the 747 be re-engined as a twin? [closed]

Since more and more airlines are dropping the 747 for the 777 or equivalent due to fuel efficiency, a theoretical question came to mind. What do you think is preventing Boeing from creating a 747 ...
chickenricekid's user avatar
13 votes
2 answers
3k views

What are these lines on the fuselage of a 747?

Have a look at this picture: It's from Airliners.net (though I've modified it a lot) and shows some lines on the fuselage. What are they? Are they ...
user13197's user avatar
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13 votes
3 answers
2k views

Why are the outboard Krueger Flaps retracted before the others on the B747?

In this video, I noticed that the outboard Krueger Flaps on this Boeing 747 were retracted while the middle and inner sets remained extended (refer to 3:22 - 3:30 in the video). My questions are: ...
pr1268's user avatar
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12 votes
3 answers
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Does Nitrogen inside commercial airliner wheels prevent blowouts on touchdown?

I just watched the first episode of Inside Mighty Machine where civil engineer-turned-host, Chad Zdenek, discussed innovations of the 747. One innovation he discussed was the increased number of ...
cfx's user avatar
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12 votes
3 answers
3k views

Can a Boeing 747 take off fully loaded on 3 engines?

Recently a Boeing 747 aborted a take off while still on the ground due to the failure of one engine. Can a Boeing 747 take off fully loaded on 3 engines?
philip's user avatar
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12 votes
2 answers
6k views

What's the maximum seat configuration for a 747 that is actually used?

I'm curious what model and configuration of the 747 has the most seating capacity actually used somewhere in the world. The Wikipedia page lists "typical" seating, maxing out at 467 (the 747-8). But ...
T.J. Crowder's user avatar
11 votes
2 answers
6k views

How much extra drag does landing gear incur?

How much extra drag does landing gear incur? I'm interested in large commercial airplanes. For a concrete example, let's say a 747 flying at 1,000 m above sea level at 800 km/h. Edit: Looks like 800 ...
DrZ214's user avatar
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11 votes
2 answers
23k views

How can a Boeing 747 take off from Princess Juliana 7,546 ft runway?

I recently read this article that talks about 747s taking off from Princess Juliana International Airport in Sint Maarten. The Princess Juliana runway is only 7,546 ft, but according to Wikipedia, ...
cph2117's user avatar
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