Hard Landings
 

Is it just me or are landings getting harder?

Recently a Ryanair flight to Ciampino landed with enough of a thump (or even thumps) to get the crew sitting in front of me pulling faces.

When asked why the landings were "so hard" the reply came back that it was for safety.

True?

Are the days of light landings over?

HALFPINT

I am afraid that you question is not sensible.

Let me firstly say that I am not an airline pilot, but I have made several hundred landings as PIC of a light aircraft and have done about 15 hours training in an airline simulator.

The point about landing any aircraft is that you need arrive within the landing parameters for the aircraft type (i.e. don't break it) and to stop by the end of the runway. Airline pilots generally aim to arrive in the first 1000 feet or 300 metres of a runway, which is known as the touchdown zone. All landing performance calculations are based on this happening.

So when you Ryanair pilot touches down firmly, s/he is ensuring that the aircraft arrives in the touchdown zone. If the runway is wet, then an extra firm arrival may be mandated to mitigate acquaplaning, by forcing water away from the tyres.

If landing in a strong crosswind, the pilots of some types may well choose to land wing down, with the result that you hear three bumps, as the into wind, downwind and nose gear all touch down seperately. Again I don't know if the 737 800 is landed this way, since the engine pods are slung quite low.

So what the crew are telling you is true and their grimaces are just a reaction to the bump as you touch down.

As I don't fly airliners, you 'll have to take the next line as an opinoin, maybe a 738 driver could help me out here, but I don't think (from visual perception when last there) that Ciampino has an enormously long runway by 737-800 standards, so I would hypothesise that the crew definitely do not want to float very far (or at all) as they flare for landing, thus firm touhcdowns may well be SOP.

Finally, don't forget that a landing that feels firm in one part of the cabin may feel like a greaser in another seat. Also aircraft do sometimes decide to go down with a bump despite the pilot's best efforts :-)

So is the era of light touchdowns over..... well I don't think that it ever started to be honest.

Hard Landings
 

Sensible or not - since I'm on the receiving end of over 150 landings a year it is quite interesting to feel the difference
between them - LGW & STN to CIA, LHR to FCO.

Ciampino is long enough for 747s so guess that isn't an issue.
(Air Force One and C5 Galaxy presidential support use it)

Last Friday (the biggest bump this year) was dry and no wind.

Landings in wet and windy have been less violent - whether Easyjet Airbus or Ryanair 737-800.

Just trying to get a consistent picture - hey doing it more than twice a week every week - you have to while away the time somehow.

Just curious - grew up, perhaps mistakenly, believing that pilots tried to execute as soft a landing as possible for the benefit and comfort of passengers.

1/2 PINTThe prime objective of pilots is to land safely, no more, no less.

This is achieved by arriving at the correct aiming point, pointing in the correct direction, at the correct speed.

If you do this then the aircraft will stop on the runway the manufacturers state.

There are paramaters that limit the vertical speed and determine what is a 'heavy' landing in terms of nomal 'g'. If these limits are exceeded engineering checks are required before next flight. For this reason, I suspect that you have never experienced one.

I know that I haven't in over 10,000 hours flying.

What you have experienced are 'firm' landings which can occur for a variety of reasons mentioned. Pilots enjoy 'soft landings' or 'greasers' as much as the passengers, but they can't be done to order as landing is an art, not a science.

The Boeing philosophy, I believe, is to fly the thing into the runway as much as onto it. The undercarriage is designed to take it and in wet conditions it can be critical to ensure the wheels spin up quickly enough to activate the spoilers and to prevent aquaplaning.

All that said however, *most* pilots take great delight in performing a nice, gentle touchdown. More often than not these happen when the conditions are most challenging, as the pilot is having to concentrate and work much harder than if it's a cavok day with 2 knots of wind.

As Topbunk says, we can't guarantee a 'greaser', but a firm landing isn't always a bad thing:ok:

I would not assume that, since the configurations of the aircraft and the subsequent performance may be surprising.

The 737 800 approaches relatively quickly, I believe and it may or may not approach faster than a 747 or C5 and may or may not require a similar or longer LDA. I notice, from the Boeing noise ababtement website, that Ciampino has 2196M available for landing - compare this with Stansted at 3148 and you will see that there is quite a difference.

Some flawed logic there I think F3G. There may or may not be some aircraft out there which would prove your logic, but as far as airliners as concerned :

The approach speed is not the deciding factor, and I'd be very surprised to find a 737 requiring more LDA than a 747, unless the 737's flaps and brakes had failed:E

The major factor in LDA is how much is required to dissipate all that energy, and a circa 200 ton jet has a lot more momentum than a 50 ton jet, even if it is going slower.

For reference, compare here : 737 perf to here : 747 perf

(Acrobat docs)

Cosmo

You're quite right - I was trying to use a non pilot friendly analogy. Halfpint had dismissed the length of the runway as a possible factor and I wished to gently challenge that.

My line of thinking was that Air Force one might be operating at very light weights (this may also not be true) and that this might skew apparent correlation.

Having looked at the perf charts (thanks for the link, very interesting) I note that a 737 at 66.4 metric tons, SL, zero wind, f40, autospoilers and autbrake op would require about 1700m LDA.

The 747-400 chart shows that a 220 metric ton aircraft, SL, 0 wind, f30 etc would need about 1600m. (Knowing very little about 747s, I don't even know if 220t is a realistic arrival weight.)

Both are well with the 2195m available at Ciampino. I was surprised it is so long frankly, it certainly did not feel that long when I went there, but perhaps we made a downwind departure giving an illusion of a shorter runway, by the perception of less time from rotation to clearing the upwind threshold.

F3G

220t for a 747-400 landing is on the light side, whereas I guess 66t for a 737 is towards max landing weight.

An empty 747-400 APS weight is about 175t. Add 400 pax and bags (40t) and freight (say 15t) and bare minimum fuel (10t) gives you 240t, which in my experiance is closer to the norm. Max Landing weight is 285t or thereabouts. Freighters will be heavier.

I have landed on 26R at LGW with zero wind and think I recall that we were at MLW at about 250t for that strip [several years ago].

Top Bunk Absolutely, I picked the MLW for the 737 and something near the bottom end for the 747, from the perf charts.

However, in reality I've no idea what weight the AF1 (747-200?) would arrive at, so the whole things is a bit of idle speculation :O

Thanks for your post, though, its always interesting to learn new things.

AF1 would have been very light compared to, say, a 747 with 400 pax and bags/cargo.

Leaving that aside I understand the 737-800 operated by FR uses steel brakes rather than carbon fibre which give it a longer landing run. (happy to be corrected if I'm wrong).

Regardless of carbon or steel brakes, CIA's runway is quite short - I believe it has a displaced threshold which give an LDA of just over 6000ft. In these situations the aircraft has to be landed firmly in the correct touchdown area. I recently landed at PIK in one of these 737s where the pilot strove for and achieved a very smooth landing. Problem was it took him 3000ft of float to do that - OK when you have 10000ft of estate to aim at (we cleared with about 1000ft to go) but try that at CIA and you would have a repeat of the Toronto situation which is not an ideal way to end a flight.

Don't forget also that Ryanair pilots aren't quite as good as the rest of us and are more likely to make 'hard landings' as they bought their licences on e-bay. ;)

Ha ha ha ha ha! Oooh Sean, you'll get in bother for that one! :D

(I heard they got them out of a cornflake packet myself).:}

Given that aeroplanes are heavy metal tubes which go very fast and very high, I think it's amazing that anyone can control them at all. I'm gobsmacked that I can sit in one of these things, travel thousands of miles and then crash into the ground so gently that I can get up and walk away.

I'm sure it's all done by magic.

I take my hat off to you drivers who work your magic on a day to day basis!

Your right, especially for Ryanair. I'm convinced that they have the worng flare technique...

Every now and again you "bang one in". It comes with the job. However, some aircarft flatter your landing technique (BAe 146, RJ family) and some others have a go at you like lightly loaded Fokkers (F70/100 and F27/50).

I thought a good landing was where everyone walked away from the aircraft and an excellent one was where the aircraft could be flown again without being repaired........

Funnily enough, one of the smoothest landings I've had for some time was an BA A319 into ARN a month or so ago, with gusty winds and lots of bouncing around on the approach. I expected a solid landing and it was as smooth as you could wish, despite the winds.

I guess it those sort of occasions that make you realise why pilots are worth what they're paid!

In my experience, the 738 is much more sensitive to slight deviations in crab angle than the 733 or 734. As a consequence, the first few meters in the landing roll of an NG may suddenly become a rumbling experience, even if you felt it was going to be a real greaser.

What kind assistance does the Airbus family offer to calculate the landing parameters? I remember reading that the VOBG/BLR A320 crash was caused because the pilot didn't follow the path suggested by the aircraft systems.

The reason a 747 / 777 / 737 have a similar stopping distances (despite being very different weights) is to do with the number of breaking wheels each aircraft has. (The approach speeds are similar for each type). The ability to dissapate kinetic energy is the key.

A 737 has 4 breaking wheels. A 777 has 12 breaking wheels. (No idea how many a 747 has). Thus, a 777/ 747 can dissapte its energy at a similar rate to a 737. Hence the landing distances are similar.