# Why do fighter jets land faster than Jumbo commercial aircraft?

From my own understanding, the bigger (and heavier) aircraft, the higher approach speed it needs to keep itself from stalling. According to this site, the approach speed of an A380 is 140 knots, and 160 knots for a 747. In contrast, the F-16's landing speed is 141 knots, and 135 knots for the F-35C.

Doing mass-to-speed ratio, it doesn't make any sense to me. Could you explain why do fighter jets land faster while they are lighter than large commercial aircraft?

• The landing speed is based on the "stall speed", which depends on the wing airfoil. A faster airfoil is not as efficient at low speed, and stall speed is usually higher. Concorde which had a faster airfoil also landed faster (155 kt), while this was a relatively light aircraft.
– mins
Jun 30 '15 at 8:18
• I'm not entirely sure you got the numbers right for your question, you have jumbo = 140-160 and fighter = 135-141 last I checked 135 is less than 140 Jun 30 '15 at 8:19
• @ratchetfreak , I am sorry if I get the number wrong. Could you provide the correct data, please?
– TBBT
Jul 1 '15 at 4:30
• Slow birds land slowly. Fast birds lands fast. Size has nothing to do with it. Jul 1 '15 at 11:14
• This question could be improved by incorporating some consideration of wing loading. If you really want to get fancy, talk about airfoils, and flaps. But as has been pointed out, the average of 140 and 160 is greater than the average of 141 and 135, so this question defeats its own premise. Apr 22 '20 at 0:02

It is not only the mass that affects the landing speed. Wing area plays an important role as well.

A larger wing can lift more weight at the same speed than a smaller wing. If you compare the wing loading of these aircraft the differences are smaller:

A388:

• Maximum landing weight: 391000 kg
• Wing area: 845 m2

B744:

• Maximum landing weight: 295000 kg
• Wing area: 525 m2

F-16A:

• Estimated landing weight: 13000 kg
• Wing area: 28 m2
• I guess you mistyped B747 as B744. Jun 30 '15 at 10:28
• Or, @sharptooth, he meant to use the shorthand for the 747-400 Jun 30 '15 at 10:58
• And, not just wing area, but wing size, shape, and AoA. Basically, what matters is the ratio of how much lift the wing produces at low speeds vs. the weight of the aircraft on landing. Aircraft wings that are efficient for supersonic flight are not efficient at low speeds and even subsonic wings are usually optimized for cruise flight speed. So, while a higher weight does mean a faster landing for the same airfoil, aircraft that are designed to fly faster will typically have faster landing speeds than slower aircraft regardless of how their weights compare. Jun 30 '15 at 16:47
• For example, some of the newer 737s, if landing near their max landing weight, land faster than an A380 or a 747 typically would land. Here one of the posters mentions that he had recently landed a 737-900 with a final approach speed of 169 kts and was gaining on the 777 in front of him. Jun 30 '15 at 16:49
• @TBBT It's probably best if you ask that as a new question. It will get better answers that way and will be easier for people to find in the future (and better indexed by Google, etc.) Jul 1 '15 at 9:37

Landing speed varies depending on several factors.

For airliners you have to take into account that the wing airfoil is radically different than the wing airfoil from a fighter jet: airliners have flaps that modifies the airfoil and doing so the lift and trail (not sure of this word in English) modifying the speed range of the wing (reducing the stall speed) and so allowing slower speed for landing.

In the case of a fighter jet the wing is in general a delta wing without flaps, so in order to reduce the speed for landing they have to increase the angle of attack to augment the trail without loosing too much lift. That why in this phase they cannot lower too much the engines and the speed, because their wings are not suited for low speeds. If you look at the Concorde (a good example of delta wing) they had to put down the nose during landing phase to be able to see the runway because of the high attack angle requested to be at the right speed (about 180-190 kt).

• Fighters more often than not have flaps, just not the big multi-stage ones you see on big airliners. Take-off and landing speeds of these planes would be totally unworkable otherwise. They also typically have air brakes allowing the aircraft to approach under higher power, again without making landing speeds unworkably high. Jun 30 '15 at 16:33
• The high angle of attack of Concorde is simply effect of using delta wing, which can naturally create lift at high angles of attack (vortex lift) and can't use flaps (they would act like elevators and pitch the aircraft down instead). The high landing speed reduced, not increased the angle of attack. Sep 22 '15 at 14:12

Because they are lighter, they have less kinetic energy so there is less to dissipate. This is easier on the brakes. Remember kinetic energy is $E_k=\frac{m \cdot v^2}{2}$.

Also fighter jets aren't as good gliders as jumbo jets. This sacrifices lift for maneuverability, so they have better acrobatic performance. While airliners will spend most of their airtime going straight ahead at high altitude so they benefit the most from being good gliders.

• But the lighter plane having less kinetic energy isn't a reason for landing fast: it's a reason not to worry about landing fast. After all, if a light plane landed slower, it would have even less kinetic energy (since ke is proportional to the square of velocity), and be even easier on the brakes. Jun 30 '15 at 11:31

To simplify, the differences are similar to comparing a dart to a glider -- it all gets back to the wings. The delta wing provides the best overall flight characteristics in terms of lift and control surface efficiency. A delta wing will allow you to come in low and slow and in control, but is that always what you need if you are flying a fighter jet? The aerodynamics of fighter jets are designed to provide lift, stability, and control at a much wider angle of attack. Comparing the wing characteristics between the two planes in a wind tunnel, notice how the wing thickness (airfoil) of the fighter plane is much less (relatively flat) at the leading edge.
Although the fighter plane provides less lift at the same angle of attack and requires a faster airspeed to stay aloft without stalling, the control over a wider range of airspeeds is worth the tradeoff for the fighter jet performance and maneuverability.

Shut down a fighter plane engine, and it will drop like a yard dart. The intake on a fighter plane is designed to receive as much air as possible, and will cause turbulence at the inlet if the blades are not turning fast enough. There simply is a minimum speed range to keep the plane in flight and under control as it is coming in for a landing.
The power to weight issue has a downside -- the fighter plane is less efficient in fuel consumption -- it is even less efficient if the inlet has nacelles or ducting to mask a thermal signature.
The power to weight ratio of the fighter plane is much higher than a commercial aircraft, and the answers above from the other posters regarding thrust cover the topic well. The best fighter jets provide the most maneuverability over the widest range of speeds.
Both types of aircraft would technically benefit from a lower landing (and stalling) speed, but in both cases, other flight characteristics are a higher priority.

Here's another factor in approach speeds - the military fighter/trainer aircraft I flew used 1.2 Vso (20% above landing configuration stall speed) for approach. Airliners are required to use 1.23 Vso and each model uses a different multiplier which often changes with different flap settings. The previous generation 727/757/767 mostly used 1.3 Vso while the newer airliners use 1.25-1.28 Vso. That difference reduces a fighter's approach speed by 4-8% vs what an airliner would use. Light airplanes use 1.3 Vso, or 30% above stall speed, for their approach speed.