Questions tagged [cruise]

The section of flight between the after takeoff climb and landing approach.

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Why is it that when autopilot is maintaining cruise, we don’t feel the changes when lift increases?

When we’re inside an aeroplane, when we’re in cruise, why is it that we don’t feel the changes in altitude, lift and the adjustments for example from the elevator on the plane as the weight is burned ...
James's user avatar
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How is an airliner trimmed nose-down or up? [duplicate]

so when a plane is in cruise, it loses weight and then the weight begins to exceed lift.when this happens, the plane begins to climb. My question is this please: The plane would be trimmed up or down ...
James's user avatar
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How does drag change efficient cruise conditions?

If I have an aircraft, and I reduce the induced drag produced by it, does this mean I should operate it at a higher altitude and faster speed to take advantage of the drop in total drag, or slower at ...
Alastair Wyllie's user avatar
15 votes
2 answers
4k views

Does flying slower actually save fuel?

Following a discussion on travel.SE, I wonder: would flying more slowly actually save fuel? I suppose that it would save fuel on a volume of fuel per flight hour basis, but the flight would end up ...
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Does cruise speed depends on rate of climb?

If an aircraft wants to fly at a fixed cruise speed, will the rate of climb have any effect on that? For example, let's assume an aircraft has to fly at a cruise speed of 0.8 Mach. How will the rate ...
Eaza's user avatar
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Does lift requirements change as fuel is burned? If so, how?

so when an aircraft flies in cruise, it burns weight and so what impact does this have in lift requirements? Would there be a need to also deflect flaps to stay in cruise as fuel is burned? — I’m ...
Minty Pythonn 's user avatar
2 votes
1 answer
219 views

Is there any existing engine which can be converted to turbofan from turboshaft in mid flight?

I read about convertible engines. I want to know if there is any engine existing to meet up hover and cruise together.
Eaza's user avatar
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Why isnt the structure of the aircraft affected by high true air speeds or high ground speeds?

Let's suppose that in Cruise flight I exceed the VNE in TAS or in ground speed, why isn't the structure of the aircraft affected by the high speeds? I am sorry for my english, I am not a native ...
Andres's user avatar
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12 votes
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Why do missiles typically have cylindrical fuselage and not a fuselage that generates more lift?

For example, Tomahawk Cruise Missile, or Harpoon anti-ship missile. They fly straight and level for the most part of their flight regime. I think if they had a fuselage optimised for level flight then ...
Tony Stark's user avatar
2 votes
3 answers
300 views

Will a heavier aircraft be more efficient at high speeds(cruise)? [closed]

Since heavier aircraft have more mass and inertia, they will have less drag because it will be easier for them to push through the air so does that mean that we can achieve the same cruise speed with ...
Fan's user avatar
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Do airliners reduce their angle of attack to maintain lift = weight as fuel burns off during cruise?

For an aircraft to remain in level flight, it must generate lift force that is exactly equivalent to its weight. However, modern airliners lose a lot of weight when they are in cruise flight in the ...
interested22's user avatar
1 vote
1 answer
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How to compute the mass flow rate for a turboprop at cruise given the static sea level value?

I am trying to obtain the mass flow rate of the Allison T56-A-15 used on the C130H at cruising altitude (so as to solve the Joule-Brayton cycle at cruising altitude). I know from "Turboshaft, ...
fras's user avatar
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0 answers
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What is the effect of aspect ratio on cruise velocity?

Does the Aspect ratio affect the Maximum cruise velocity please? I was thinking it wouldn’t as Aspect ratio= b^2/S. If I wanted to go quicker I could just increase my span and decrease S?
Peter Warennn's user avatar
4 votes
1 answer
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Why do B787 Dreamliners more often fly at 42,975 ft rather than at 43,000, according to flightradar24?

The A350 and the B787 are the only passenger airliners that can be seen cruising as high as 43,000 ft on flightradar24 (with the exception of a B747 I once saw). However, the B787 is more often found ...
Better not tell's user avatar
18 votes
5 answers
5k views

Would an airliner climb higher late in the flight because of the consumed fuel (lighter airplane) to save more fuel?

Some people said airplanes would fly higher in the late period of each flight, because the fuel is consumed, and the airplane is lighter. Higher altitude and less dense air is enough to support the ...
Westack's user avatar
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1 answer
322 views

Does the optimum LRC speed increase or decrease as the GW of the aircraft decreases during a long range flight?

I do not know what defines the optimum LRC speed for each aircraft, aeronautically speaking. I suspect it has something to do with optimum AoA but even then I am not sure if the LRC speed should ...
Stamatis Vellis's user avatar
14 votes
2 answers
6k views

Why are planes required to cruise at round flight levels only above 18000 ft of altitude?

AFAIK, planes flying at up to FL180 (18,000 ft pressure altitude) are allowed to fly at both round and semi-round altitudes (e.g. 15,000 ft or 15,500 ft). Planes flying above FL180 must fly at a round ...
Giovanni's user avatar
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6 votes
1 answer
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How to most likely get a flight that will go above 40,000 ft?

I wonder if there are passenger flights that would reach cruise altitudes higher than 40,000 ft (i.e. reach 41,000 ft for instance) more likely than others. It also depends on the plane of course, but ...
Giovanni's user avatar
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2 answers
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Do most commercial jets cruise at constant altitude/speed?

The weight changes throughout, so this means aerodynamics efficiency changes to maintain constant speed and altitude. Is this how most commercial jets cruise?
stevederekson555's user avatar
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Aircraft thrust calculation

I had a question regarding thrust calculation for an aircraft during cruise. For an aircraft flying at a constant cruise altitude and a constant Mach number (level unaccelerated flight), what exactly ...
Harjot Singh's user avatar
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1 answer
147 views

Descent of Light attack aircraft to loiter altitude

How do Light Attack Aircraft (LAA) such as the Embraer Super Tucano descend from their cruise altitude to their loiter altitude to be on-station above ground troops? I want to know the way these ...
Pavan's user avatar
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3 votes
2 answers
503 views

Optimizing the airplane for best cruising altitude and velocity

In the conceptual phase of the design, I am optimizing various entities of an airplane for the best cruising altitude and speed to reduce the cost, which also includes MTOW and fuel weight. Consider a ...
Pavan's user avatar
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1 answer
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Relation between weight of the aircraft and mach number [closed]

Is there any formula that relates weight of the aircraft with mach number?
Nawaz Sharif's user avatar
6 votes
1 answer
5k views

How is the Dash 8 Q400 so fast?

The Q400 has a cruise speed of 360kts, and on flightradar24 most Q400s that I looked at reached similar speeds during cruise. The ATR 72 has similar specifications yet only flies at 280kts. I'm ...
Rory McDonald's user avatar
1 vote
2 answers
4k views

How much thrust is produced on an A320 at takeoff and during cruise?

Where can you get the drag polar of the A320 at cruise and TakeOff?
Daniel's user avatar
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7 votes
1 answer
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Based on this fuel flow chart, why isn't it more optimum to remain at an intermediate altitude rather than climbing?

I am having a bit of confusing as to why people say planes gets more efficient as they fly higher. Because on a typical long haul flight the Fuel Flow of the aircraft will obviously be much more that ...
Joe Wie's user avatar
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7 votes
3 answers
4k views

Do pilots keep light in the cockpit during long night flights?

During long times of the cruise flight, is the internal light normally switched on or off inside the cockpit? Knowing it is generally dark in the night would make a smartphone-based night time logger ...
h22's user avatar
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Relationship between wing aspect ratio and speed [duplicate]

For some reason, I cannot find a relatively straightforward source online which discusses the relationship of wing aspect ratio and how it affects speeds of an aircraft. Specifically, is there a ...
sethkim's user avatar
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2 votes
1 answer
1k views

Why is the thrust-specific fuel consumption much worse for high bypass turbofans at cruise?

General Electric GE90 Takeoff: 0.278 lb/lbf/h (28.3 kg/kN/h) Cruise: 0.545 lb/lbf/h (55.6 kg/kN/h) Source: https://en.wikipedia.org/wiki/General_Electric_GE90#Specifications I assume this is typical ...
Abdullah is not an Amalekite's user avatar
24 votes
4 answers
6k views

Why are heavy flaps better than just a bigger wing?

Flaps increase lift during landing and T/O. But when retracted, they do nothing. The space needed to stow the common fowler flaps can't be used for anything else - fuel or structure. Extended flaps ...
Abdullah is not an Amalekite's user avatar
4 votes
1 answer
3k views

Cruise Mach Number less or more than Critical Mach Number

Do commercial airplanes cruise at Mach number higher than the critical Mach number? And what is the critical Mach number of airplanes like B777 or A330?
Pavan's user avatar
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2 votes
2 answers
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What is the main reason why cruise flight in the transition layer is prohibited?

What is the main reason why cruise flight in the transition layer is prohibited? For example if we have a separation of 1000 ft between transition altitude and transition level, why should we not ...
Hamid's user avatar
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1 vote
3 answers
820 views

How long is a climb leg in a step-climb cruise flight segment allowed to take, according to regulations (FAA/EASA)?

I am working on a trajectory optimisation program for commercial, large aircraft, in which I want to incorporate realistic air traffic control regulations. One of the constraints I want to incorporate ...
Sam's user avatar
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17 votes
5 answers
7k views

How do planes maintain constant speeds at cruise altitudes?

I'm a noob so pardon my ignorance. So my understanding is that as the plane gets lighter during the flight, its mass reduces therefore reducing the lift needed to maintain the altitude. At those ...
Sriram Subramanian's user avatar
0 votes
1 answer
597 views

Tiny margin between VFR cruise and over Class C?

Our class C airspace at KRDU has a 4400 ceiling. If I fly Westbound above the airspace at VFR cruise, I'm expected to be at 4500. Since this is a tiny margin and I don't want to bust into the airspace ...
saigafreak's user avatar
1 vote
1 answer
2k views

What is nominal n1 and fuel flow behavior during cruise climb?

For a commuter airliner (e.g. 737) performing a cruise climb (step climb) at a constant Mach, how should n1 and fuel flow behave? I know that fuel flow should decrease with altitude (air fuel ratio). ...
mdamkani's user avatar
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3 votes
1 answer
2k views

Does the Enroute Phase begin at a 30NM distance from the departure airport?

ICAO's Doc 8168 Volume II ("Aircraft Operations") states: Part III "Performance-Based Navigation Procedures" Section 1 "Underlying Principles" Chapter 1 "RNAV ...
Vector Zita's user avatar
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30 votes
6 answers
5k views

Why cruise at 7000' in an A319?

I was on a flight from Philadelphia (KPHL) to Boston (KBOS), after some delay and some change of route due to weather, the captain announced that we will be cruising at 7000' due to delays in the area....
Brice's user avatar
  • 452
14 votes
4 answers
6k views

How do planes know what altitude they're cruising at?

I know that when planes enter the aerodome containing the airfield of destination, the ATIS will tell them an altimeter setting so the system knows how to calculate their altitude above their field; ...
WildGurgs36's user avatar
2 votes
1 answer
96 views

Learn in-depth about airplane operations [closed]

Currently seeking a book or manual that teaches a civilian how a cargo aircraft operates and what it's pilots do, say a 787. Preferably a high-level overview at a per flight phase: Pre-flight: Flight ...
Alexis Moreno's user avatar
11 votes
1 answer
631 views

Is there research suggesting that VFR cruise altitude rules improve safety?

In the United States, 14 CFR 91.159 prescribes cruising altitudes for level flight under VFR: (a) When operating below 18,000 feet MSL and (1) On a magnetic course of zero degrees ...
Tanner Swett's user avatar
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0 votes
2 answers
537 views

Why is the normal operating airspeed so much lower than the cruise speed in this table?

I need to work with the following table. I'm interested in vMO which I assume I can simply obtain from converting MMO to vMO through $M = v/ \sqrt{1.4 * 287 * T}$. (Is that correct?) However, I ...
Daniel's user avatar
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1 vote
1 answer
743 views

Why would a plane drop 14.000 ft mid flight?

Just noticed American Airlines flight 221 dropped 14.000 ft mid flight today. Curious, what could have caused this? Here are the flight details.
M Daniel's user avatar
6 votes
3 answers
454 views

Can airplane performance be increased by cruising "on step"?

Old timers swear aircraft performance can be increased by getting an aircraft "on step" similar to how boats are operated. They claimed a couple extra miles per hour (airspeed was in MPH then) were ...
jwzumwalt's user avatar
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4 votes
2 answers
2k views

What is the throttle setting of a piston aircraft during cruise?

I am learning to fly nowadays, I am sorry if this sounds like a dump question. What is the throttle setting of an aircraft during cruise flight? After stabilizing the flight after climb do i need to ...
Jijo John's user avatar
  • 171
5 votes
1 answer
1k views

What happens if full thrust is applied at cruise altitude for 5-10 minutes on a 787?

What happens when you apply full throttle to the engines of a Boeing 787 at cruise altitude for 5-10 minutes? Other than wasting fuel, what maximum speeds are reached? Does that pose any danger or ...
securitydude5's user avatar
1 vote
1 answer
1k views

What VFR cruising altitude should be flown to the west below 4500 feet?

This is similar question to this question, but different scenario. Let me describe the situation: I am at KDYL in class G airspace. Accroding to ATIS the clouds are at 4700 scattered. I am going to ...
Igor Levashov's user avatar
0 votes
1 answer
335 views

How do single GA pilots prevent boredom during long flights? [duplicate]

My question somehow relates to this question asking about how pilots cope with boredom, but now the scenario is not the typical airliner configuaration with two pilots, but with only one. I'm thinking ...
Stefan's user avatar
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7 votes
2 answers
15k views

What throttle setting does an airliner use while cruising?

As a passenger, I have always felt like the engine are not kept at take-off thrust/full throttle a few (tens of) seconds after take-off, and so for obvious reasons as fuel efficiency, engine wear ...
le_daim's user avatar
  • 400
2 votes
2 answers
4k views

What is the Fuel-Oxygen ratio for a large turbofan at cruise conditions?

What is the Fuel-Oxygen ratio (by mass) for a large turbofan at cruise conditions? In order to be concrete, I'll just pick an engine at random. I pick the GE90-115B. Okay it's not really random, it'...
DrZ214's user avatar
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