KLM bad landing....LOL

[Cargo_ramp]

Would like to know the stall speed of a B767-300ER. Was flying into AMS from YVR on KLM and as A/C flared it just crashed down.(I know thats sounds really dramatic, but was a really rough landing)...certainly not a greaser..speed on approach was about 138kts. Didn't feel windy outside (went out side for smoke..after cleared customs). For all the members...i love flying, i'm not complaining..just wanna know poss reasons for flying so slow on approach? Thought about ATC slowing us down for A/C still on runway..and also at height we were at was there a head wind..strong enough to warent the approach speed..

Any suggestions?

[Bealzebub]

The stall speed is fairly irrelevant. It is a function of weight and configuration ( flap/slat setting). If you want a rough guide probably somewhere around 100 kts.

An airliner uses approaches speeds that are based on a "Reference" approach speed. This is roughly 30% higher than the stall speed for any given flap (and associated slat) setting. The approach speed is then adjusted to take into account steady headwind component and any gusts etc up to a maximum value ( usually around 20 knots). For a Boeing 757 with a landing weight of around 90 tonnes on a landing with a steady headwind value of say 10 knots a Vref 30 ( that is planning to land with a normal 30 flap setting) would be around 132 knots with an approach increment of 5 knots giving an approach airspeed of 137 knots ( once 30 flap had been lowered). It would be around 20 knots faster for each of the previous flap settings. I dont have the figures to hand for a 767 but I doubt they are wildly dissimilar.

I have to say I am impressed that you could ascertain as a passenger in the cabin the speed was " about 138 knots". I have been doing this for nearly 20 years and don't think I could make such an accurate guess. Nevertheless as you can see 138 knots would probaly be about right. The approach speed is a speed through the air ( the ground speed is incidental). If there was a 50 knot headwind component the 138 knot airspeed would have been an 88 knot groundspeed and presumably would have looked more like 88 knots to your eye. Speed on the approach can be varied and aircraft are often asked to slow down early. However this simply requires the use of more flap at an earlier stage and flying to the Vref schedule. No one would fly at less than the final approach speed.

Landing is still a bit of an art and sometimes we all do ones we are proud of, and as if to keep us in check we are also blessed with the odd thumper. On the whole most are average and of course that is how they should be. Sometimes people fail to realize that there are more important considerations than achieving the smoothest touchdown. Aiming for the correct touchdown point is a more imporatant consideration as is ensuring that a very smooth touchdown on a wet or contaminated runway doesnt result in aquaplaning or otherwise compromised braking action ( neither of which would be too clever).

hope this helps answer your question.

[Cargo_ramp]

Cheers for the reply..

The reason I knew the speed of the A/C as we came into land was that KLM has infomation flash up on monitors every 10 secs about the A/C's height, speed, distance from destination etc, so as I saw from my window the airport lights the monitor told me the speed (138kts) and the height from the ground. I wasn't trying to be smart because I know on this website theres too many people waiting in the isles to correct u...(which is fair enough) I wasn't complaining about the landing as such, just wondered about the speed..thanks for the explanation...

[TopBunk]

Cargo Ramp

Just a thought, maybe the speed they show you on the display is groundspeed? If so, the airspeed would have been increased by the headwind component/decreased by the tailwind component.

Nonetheless, 138kts sounds about right (although I've never flown the 767). I would give approach speed ranges as 120-135 for A319/737-200, 125-143 for 737-400/A320, 140-160 for 747-400. From this I infer 767 approach speeds in the 135-150 range.

HTH

[PAXboy]

(non pilot speaking) I understand that one of the causes of this kind of event is air currents swirling around airport buildings. For example, at LHR, the maintenance hangers at the eastern end, can produce a strong current across the runway at the critical moment.

Also, the head wind can vanish suddenly and other unexpected changes in wind. If the machine is only four or five feet above the ground with a steady sink rate - when this kind of wind change occurs - there is nothing that can be done and the shock absorbers will earn their keep.

[reverserunlocked]

Well I'm typing this at Schipol airport having just stepped off the aforementioned 767-300 from Bahrain.

And did we have a bit of a clanger landing...... :ouch:

I've noticed generally you get a firmer touchdown in the 767 than other types, such as the 757. Maybe it's because the trailing gear trails forwards rather than backwards???

[Final 3 Greens]

Ladies and Gentlemen (who are not pilots)

Please remember that the objective of a pilot landing an aircraft is to land consistently within the touchdown zone on the runway, within safe parameters.

This does not mean that a gentle landing will always be the result.

I'm only a PPL, but I had the very great fortune to spend some hours in a simulator with an airline instructor (IRE/TRE for the pilots reading.)

I learned under his excellent tuition the above information and also the fact that landings can 'feel' different depending on where one is sitting in the aeroplane.

So whilst some airline landings may feel firmer than others, professional pilots keep us safe and even their 'bad landings' (by their own standards) are generally impeccably safe. (and they make amateur pilots like me feel much better when we 'arrive' rather than land!!!)