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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How was the 747 and DC-10's trimmable stabilizer actuated?

I was recently reading about Alaska Airlines Flight 261, a crash where understanding it in detail requires a bit of a deep dive into the trimmable stabilizer. On that particular aircraft (MD-80), it ...
3 votes
1 answer
171 views

Why does the maximum allowable load factor vary with airspeed in some aircraft?

In this ASE answer What is the maximum safe bank angle of a 747?, the author writes: If we stay with stationary turns (without the "falling out of the sky" part), the maximum bank angle is ...
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 ...
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1 answer
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Why some airliners have autostart and others don't?

So some of the more modern FADEC equiped planes (specifically airliners like the 787) have autostart and will self monitor the engines during startup. The one thing that confused me was how a 747 ...
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1 answer
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On the B737 When A and B systems are pretty much each other's back up for most things Why not for flaps? [closed]

Why have a seperate system for flaps? Which is alternate flaps
14 votes
1 answer
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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.
7 votes
3 answers
753 views

What would be the minimum number of engines required to climb in a 747?

There was a really good Air Crash Investigation by Nat Geo which showed the British Airways Speedbird 9 issue where volcanic ash swept over all four engines and through the air vents inside the cabin. ...
16 votes
1 answer
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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
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What flaps are used for, if the aircraft has already landed? [duplicate]

When watching the below clip in the final approach sequence we can clearly hear setting flabs to 1, 2 and then to maximum. At 12:05 into the clip, when fully landed ...
3 votes
1 answer
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Precautions for LauncherOne off centerline drop

Virgin Orbit's LauncherOne is carried in the spare engine position of its 747 carrier aircraft inboard from the inner engine on the portside wing. At launch, the orbital launch vehicle is dropped from ...
1 vote
1 answer
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Can a 747 airfoil be scaled down for smaller jet planes?

At the loss of its acrobatic ability, could an airfoil similar to the 747 be downsized to allow a small jet to climb higher and extend its range? This plane with its wing profile is highly acrobatic, ...
9 votes
1 answer
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Could the filming of the 747 in "Awakenings" have taken place during the 747 flight testing?

In the 1990 film "Awakenings", the main character Leonard awakens after suffering from a catatonic illness for 30 years. There's a scene where Leonard watches a 747 landing in New York at JFK. This ...
4 votes
1 answer
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What is the structural significance of 'dimples' on the fuselage of a Boeing 747?

I recently watched the following video: In the video there is a mention that there are 'dimples' visible on the fuselage of a Boeing 747, when it is on the ground. It ...
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What is the thrust specific fuel consumption of a JT9D engine used for the Boeing 747SP?

I searched every inch of the internet still couldn't find the value of JT9D thrust specific fuel consumption (TSFC) , I just found the SFC which is around 0.37. Can anyone help please?
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What are the procedure for a B747-400 wheel change?

And what are the required tools? I am fascinated by how you do a B747-400 wheel change.
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1 answer
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What is considered a positive rate?

I'm a beginner pilot, and i am trying to perfect my takeoff. What vertical speed is considered a positive rate in a Boeing 747? Thanks in Advance
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1 answer
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747 Fuel Drain Ports

I read about the fuel systems on aircraft for a project I'm working on, and I was wondering about the "fuel drain ports" mentioned, which the document stated were used for complete drainage ...
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How did the 747SR fly from Qatar to London?

The following photo on the Boeing 747 Wikipedia article reads: Qatar Airways 747SR-81 landing at London Gatwick Airport in 1996. How did the 747SR manage this flight [on a regular basis]? The only ...
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1 answer
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Can a normal jet bridge reach an upper deck?

We have planes with an upper deck since the time the B747 was born. Now we have the A380. I wonder if a normal jet bridge can reach the upper deck of both planes? The scenario in my mind is if an A380 ...
11 votes
1 answer
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How heavy are the Boeing 747 landing gear?

Does anyone know how heavy are the combined landing gear on a Boeing 747? It would be interesting if someone has also weight statistics per gear (nose gear and the four other main gear).
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4 answers
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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 ...
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2 answers
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How tall is the 747-300 without the tail height?

I know that the 747-300 tail height is 63'5", but how tall is the fuselage alone? Also, what is the height of the cargo area and main cabin?
6 votes
1 answer
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What is the purpose of an inboard aileron? [duplicate]

I've noticed that larger Boeing aircrafts (such as the 777, 767, 747, etc) are equipped with inboard ailerons. What is their purpose and why hasn't Airbus incorporated them on the A330 or the A340?
67 votes
9 answers
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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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What’s the horizontal and vertical tail airfoil and volume of 747-400? [closed]

What’s the horizontal tail volume coefficient of 747-400? What’s the vertical tail volume coefficient of 747-400? What’s the horizontal tail airfoil of 747-400? What’s the vertical tail airfoil of 747-...
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 ...
7 votes
3 answers
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How many 747-200 are still in service?

I'm wondering how many 747-200's are still in service? I know for sure Rolls Royce is using one for testing purposes. And the one from the US Forces. Are there any civilian operated ones left? Does ...
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What is the optimal wing sweep angle for a passenger airliner?

There are many different types passenger planes, but is there a optimal wing angle for these planes, that improves the plane's take off speed for example, or the fuel efficiency The Boeing 747 has a ...
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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 ...
4 votes
1 answer
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What is the tapered cone on the B747 CF6 engine inlet cowling?

B747 and B767s are supposed to be using exact same GE CF6 engine, and as such their components are interchangeable including inlet cowl as they show to be effective in the IPC. However some of the 747 ...
8 votes
2 answers
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Why does a Boeing 747-8 take more runway length to take off, compared to an Airbus A380?

The Airbus A380 is the largest passenger airliner. That also includes the Boeing 747-8. Meaning, the Boeing 747-8 is smaller than the Airbus A380. As far as I know, smaller planes use less runway ...
15 votes
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 ...
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What is the exact wing chord length and thickness for Boeing 747?

I can't find this info anywhere and all they give me is the ratio. However, I need the exact/approximate values
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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: ...
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Why doesn't the 747 that is testing the GE9X have winglets?

Why doesn't the 747 that is testing the GE9X have winglets? The news says it is a 747-400, but it doesn't have winglets.
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1 answer
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Are the emergency exits on a Boeing 747-400 plug doors?

Rossiya Airlines flight FV5625 to Antalya suffered an incident at the gate when a passenger opened an emergency exit (seems to be the L3 door, from what I can tell) "because they felt too hot&...
12 votes
2 answers
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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 ...
2 votes
1 answer
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What are these holes at the rear of 747s?

What are these two holes at the rear of most 747s? I've found plenty of answers for the holes on the front of the wing box, but no answers about these back holes.
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1 answer
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Reducing popularity of 4 engine aircraft [duplicate]

We can see that now most latest airplanes by Boeing and Airbus like 737 max or A350 have twin engine configuration instead of 4 engine. And many airlines are discarding iconic 747s and A380s. What is ...
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1 answer
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How can I know the manufacturer of the PFD (Primary Flight Display) of the current mainstream passenger aircraft?

I'm developing a computer vision software based on the photos of these PFD (Primary Flight Display). How can I know the manufacturer of these PFD of the current mainstream passenger aircraft: B737. ...
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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 ...
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1 answer
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How many LRUs are there in modern aircraft like a Boeing 747 or an Airbus A380?

I work in the Avionics industry. I always wonder, how many Line-Replaceable Units (LRUs) are present in modern aircraft like A380 and Boeing 747. I understand that number of LRUs varies from customer ...
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1 answer
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Why did TWA800 not stall?

I believe the NTSB account, but based on this graph, http://twa800.com/lahr/zoom-climb.htm, why did the flight not stall after the nose separated?
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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?
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1 answer
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Why was the Boeing 747SP unsuccessful?

Why was the 747SP not very successful with sales and longevity in service with the airlines that did purchase it?
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Why are the largest civilian aircraft not adapted for military use?

Frequently, civilian aircraft models are militarized, e.g. into the role of tankers, AWACS and others. In this militarization, we see a lot of "medium-large" aircraft, such as B707, A330. The super-...
4 votes
1 answer
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How fast can an airliner (like a Boeing 747) taxi backwards?

Forgive my lack of understanding, I thought I'd just buy a simulator and mess with it. I really don't know much of anything in terms of MSFS2020 or simming really at all. I realize that airliners can ...
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3 answers
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Is it possible to buy a retired Boeing 747 aircraft?

American airline companies landed their last passenger 747 jet into retirement last year citing higher costs of flying this aircraft in comparison to modern widebody twin-engine aircraft designed for ...
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How much thrust is required for a Boeing 747 to "keep flying" at 4 km altitude?

Not full power, just enough to keep the plane moving at 4km altitude.
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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 ...