A message from our CEO about the future of Stack Overflow and Stack Exchange. Read now.
20

You have not defined your benchmark/reference value, but a three-year-old article suggests this was possible depending on definition even at a very early stage for some airlines: ANA earlier this month was the first to reveal that its aircraft were producing around 21% lower fuel burn on international flights compared to the 767-300ER that the 787 is ...


19

Boeing had already a fuselage for the 757 that fit the bill. It came originally from the 707 via the 727. To accommodate more baggage, the rear fuselage was deeper, as on the 737. During development Boeing engineers were afraid that directional stability might be insufficient with a deeper forward fuselage, so the lower half of the fuselage was kept from the ...


18

Gravity/freefall backup (or more precisely some backup) is mandatory, but in large aircraft running pulley from cockpit to the wheel wells to release the uplock (the thing that keeps the gear retracted) mechanically would be too complicated or the force required to operate it too large, so the uplock still needs to be released electrically. Unfortunately ...


16

One of the standard instruments of an aircraft is a "Pitot tube". This instrument allows measurement of the forward air pressure as the aircraft moves through the air. By this measurement the instrument can estimate the relative air speed of the aircraft. In order to make the measurement, the forward air pressure is compared to the side air pressure and the ...


15

Wikipedia's B787 article states that: According to data from launch customer All Nippon Airways, the 787 surpassed the promised 20% fuel burn reduction compared to that of the Boeing 767. This newer (8 months old) article states that: Air Canada and Japan Airlines are on the way to achieve it.


12

As the other answers say, ANA is happy with the 787 surpassing the 20% fuel savings. But that does not mean for any given trip a 787-8 burns 20% less fuel than a 767-300ER. Which makes your point about Air India valid, here's why: It's not a fair comparison. The ANA 767-300ER on transpacific routes is not in its natural habitat, i.e., it can fly the mission,...


9

Aircraft selection for a particular route is quite complex, especially for a large airline that operates many different types of aircraft. You're correct: generally speaking widebody aircraft are used for longer flights, but there are a number of other factors at play. Some of these could be that a route has a very high peak demand, where a lot of people ...


8

It's very difficult to answer this question directly, mostly because that the costs you or I would face when undertaking such an endeavour are primarily capital in nature. For a large airline (or other organisation), they'd have staff and equipment on hand already, and the price an organisation like BA or BAE pay for parts is almost certainly different to ...


7

The airplane instruments that need barometric data, airspeed, altitude, vertical rate and all that, need to have a connection to the atmosphere that reads the true ambient air pressure unaffected by the dynamic factors going on in the air stream. You can't measure the air in the pressure hull for obvious reasons, and you can't just measure the pressure in ...


6

The size of the airplane mostly determines how many people it can hold (around 275 passengers for a B767). If Edinburgh to Heathrow is common route for businessmen and woman who commute often then using a larger plane is more economical for the airline. Using something such as a Bombardier Q400 which is a common "puddle jumper" airplane might cost less per ...


6

(NASA) On average, the elliptical fuselage of the 767 is 1.34 m (~4'4") wider. The fuselage dimensions are: Height Width Area (m^2) Boeing 767 5.41 5.03 21.4 Boeing 757 4.01 3.76 11.8 The slightly wider fuselage results in double the cross-sectional area. That's enough to double the drag. The slightly narrower ...


5

This research paper may be of interest for you. According to their data the 777 burns about 250Kg of fuel on taxi on average with a few data points showing burns well over 700Kg of fuel. This paper which quotes the previously linked paper talks a bit about different fuel saving methods and their impacts, like single engine taxi and what not. In short taxi ...


4

The -400ER was a strategic response to the Airbus A330-200 ... but it didn't have the range and ultimately didn't sell well. If you can get the customers who want to replace their DC-10s and L-1011s with the more comparable A330-200 (which entered service in 1998) in talks about the 767-400ER, you have a shot at selling the bigger 777 as well. But if you ...


4

Wikipedia says, Shortly after the evacuation, a team from the Polish State Commission for Aircraft Accident Investigation arrived, and discovered that the C829 circuit breaker, which protects a number of systems including the alternate landing gear extension system was "popped". The C4248 breaker for the alternate landing gear remained closed. After ...


4

The only formal classification of door types that I could find is in 14 CFR 25.807, which specifies the emergency exit requirements for transport category aircraft. It defines Type I-IV, Type A-C, ventral and tailcone exits. The doors you usually enter and leave the aircraft through are probably type I or A: Type I. This type is a floor-level exit with a ...


4

According to Boeing (on the "interesting facts" page on the (former) tour website for their Everett facility) their 767 aircraft contain... ...3.1 million parts in a 767 provided by more than 800 international suppliers. Boeing 767 Facts - Boeing.com


3

A Real-World example: On a typical 3,551 NM airways distance flight a 365,000 lbs 767-300ER will take 08:40 and 92,300 lbs of fuel to get there with 216 pax and baggage (no cargo). The flight took longer due to 51 kts of head wind that turned the 3,551 NM into a 3,973 NM air miles (ESAD) flight. A 424,000 lbs 787-8 will do the same mission in 07:56 and use ...


3

It's pretty clear that operators of the 767-400ER knew what they were doing when they selected that aircraft. Only United and Delta bought them and they are still in service even as older 767 models are being retired. The 764s have proven to be a good value proposition even though it did not sell well and is a unique bridge between smaller and older 767 ...


2

According to this document/study guide Flap Load Relief – on the 757 and a few 767s, if the flaps are at 30 and Flaps 30 speed is exceeded, the flaps automatically retract to 25. On most 767s, if the flaps are at 25 or 30 and the placard airspeed is exceeded, the flaps automatically retract to 20. The flaps will automatically re-extend when ...


2

The nozzle, apart from its main function, that is accelerating the air in order to propel the vehicle, it determines what goes into the front of the engine, it is a downstream restrictor along with the turbine nozzle. The areas of both the propelling nozzle and turbine nozzle set the mass flow through the engine and maximum pressure. For different engine ...


1

I take value proposition to mean criteria used by a purchaser to determine which aircraft to buy. Excluding financing deals and fleet commonality, the main criteria used when purchasing an aircraft are capacity, range, and seat mile cost. 3 class capacity of the 767-400 is 243 vs 301 in a 777-200er. range is 5600kt vs 7000kt respectively. seat mile cost is ...


1

You've asked about different doors. I'll skip the standard, rectangular pull in/push out door and the L1011-style door you've mentioned. Some examples:


Only top voted, non community-wiki answers of a minimum length are eligible