# Is the climb rate different for short-haul flight and long-haul flight?

A short-haul flight does not spend much time in its cruise level (let's say less than two hours). Thus, it is important to rapidly reach the optimal flight level and I think this kind of aircraft should be optimised to climb. On the opposite, on long-haul flights there the climb and descent reprsent a tiny portion of the whole flight. The aircraft should then be optimised to consume as little fuel as possible during cruise, even if climb rate is less important. That's why I wonder if my thinking is right and if there are significant differences in climb rate between short and long-haul aircraft.

Related thinking: On average, does a short-haul flight descent more rapidly than a long-haul? I think not as this diving has no reason to be related to climb/cruise performance and all commercial aircraft are made to use the same airports with the same approach pattern; but that's only an assumption.

EDIT: OK, the quantity of fuel is quite important. I suppose an aircraft designed to be heavier (long-haul, carrying lots of fuel and payload) is equipped with more powerful engines and thus if it is lighter than designed for (lets say a B777 or a A330 used on short-haul flights), it climbs faster than the same aircraft in a long-haul flight. But the long-haul aircraft is designed to make long-haul flights. Maybe I should have asked if there is a significant difference in climb rate between short and long-haul aircraft at their maximum operating take-off weight.

• The bigger difference is less fuel and consequently weight on the short haul flight that allows the plane to get higher quicker. – ratchet freak Sep 15 '14 at 14:20
• @ratchetfreak Yes, and I suppose the maximum takeoff wheight (including the fuel capacity) is a key figure to choose the total trust. A by-design lighter aircraft will have less powerful engines, conterbalancing the weight advantage for climbing. – Manu H Sep 15 '14 at 14:33
• @ManuH I think the interesting case is comparing the same aircraft on short and long hauls rather than comparing different aircraft where there are many other factors getting in the way of a clear answer. So maybe answerers could pick some specific aircraft and compare the different situations for them. – BSteinhurst Sep 15 '14 at 14:54

## 3 Answers

Different climb performance is indeed indirectly linked to the length of the trip, but this has to do with the number of engines. All airliner's engines are sized to support flying with an engine failure right after take-off. Twin-engined aircraft enjoy slightly less stringent rules, but will basically carry twice the thrust that they need to stay aloft, so more excess power is available than in four-engined aircraft, which have only 33% excess thrust.

Generally, the best performance is achieved when running the engines at their maximum continuous thrust setting and when climbing as fast as possible. That is the reason why an A-320 or a Boeing 737 will climb faster than an Airbus A-340 or a Boeing 747. On descent, the number of engines is less relevant, so the descent speeds of all types are similar.

The link between engine numbers and range was strongest in the early jet age; now it is less clear-cut with long-range airplanes like the Boeing 777-200 LR or short-range airplanes like the BAe 146.

No, not for the reasons you ask about.

Absent restrictions due to other traffic, terrain or weather, pilots will always choose to maintain the best rate of climb speed ($v_y$, a.k.a. "green dot speed") and run the engines at the recommended climb power, simply because that's when the plane flies most efficiently. The actual performance differs due to weight and weather, but that is not directly related to length of the flight leg.

Similarly the descent is again flown in a way that makes it most efficient (I believe that means close to maximum rate without speed brakes), which is again not directly related to length of the flight.

What short flights do is stop the climb at lower altitude (than permitted by load), because the time spent on higher level would be too short for the lower fuel consumption to offset the additional fuel needed to get there.

Short answer: yes.

Long answer: on a long haul aircraft, it carries a lot of fuel for the next 12 hours. That extra weight has quite an impact on climb performance. E.g. it takes more time for a fully loaded B777 to climb to 10000 feet, compared to a B777 configured for short haul. (Yes, many Asian airlines use B777 for short haul trips. The shortest one I can think of is CX flying Hong Kong to Taipei, a trip less than 2 hours)

Long haul flights also just cannot climb that high. The pilots can crank the engines max and it'll just go perhaps FL270 - FL300. Once after few hours, they burn up some fuel than climb, up to FL390 or higher. These are called step climbs : burn some gas, climb a bit, burn some more gas, climb again, and so on.

• You mention different reasons than in the question, so I believe your short answer should really be "no". – Jan Hudec Sep 15 '14 at 16:28
• Long haul flights also carry less passengers and cargo. I don't think weight is a big issue here as T/O weight for both flights will more or less be the same (One carries more pax and the other more fuel). Modern jet engines are extremely efficient at higher altitudes (FL300 and above) so you want to be there as fast as you can, irrespective of the sector. – stali Sep 15 '14 at 17:03
• @stali: The TO weight of long haul flight is way heavier than short hauls. Take again the B777 for example - TOW for VHHH-RCTP, full load is 495. Max TOW is 768. Unit is 1000 pounds. – kevin Sep 15 '14 at 19:49
• @kevin Sorry to ask but how do you obtain TOW of 495k lbs.? Is it publicly available? – vasin1987 Feb 13 '17 at 17:56