Phew!
Join Date: Feb 2008
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who got us down at BHM yesterday
BHM = Birmingham, ALABAMA
BHX = Birmingham, UK
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Birmingham cross wind landing
The pilots manual for my aircraft states a maximum crosswind limit. Are these aircraft shown in severe crosswind conditions not exceeding the
limit for their aircraft types ???
limit for their aircraft types ???
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The correct procedure is to divert to an airfield with a runway in a more appropriate direction.
Busting limits is stupid and dangerous. We dont know for certain that the limits were broken in this case but it looks like it from the pictures.
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X-wind limits
You might get one commercial pilot risk it, but I don't think so many commercial pilots would exceed A/C limits. If it goes wrong - they would be blamed and that would be a career limiting move.
It's not the cross wind that's the problem, it's the associated turbulence.
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Another manifestation of getthereitis.
The correct procedure is to divert to an airfield with a runway in a more appropriate direction.
Busting limits is stupid and dangerous. We dont know for certain that the limits were broken in this case but it looks like it from the pictures.
The correct procedure is to divert to an airfield with a runway in a more appropriate direction.
Busting limits is stupid and dangerous. We dont know for certain that the limits were broken in this case but it looks like it from the pictures.
I'd bet a substantial amount that they were all operating within the limits of the relevant AFM/OM. If we diverted every time there was a crosswind, Leeds, Birmingham et al. wouldn't see much traffic.
This youtube poster (flugsnug.com) has many videos of aircraft at BHX landing in tough conditions - I don't imagine anyone apart from the crews and air traffic knows what the actual weather conditions are were on any of them.
I guess that if "flugsnug" parked him/her self at the end of many runways throughout the UK, or for that matter many other countries similar videos could be made.
Sadly, now "The Torygraph" has found the youtube channel BHX will become the "wind capital" of the UK.
I guess that if "flugsnug" parked him/her self at the end of many runways throughout the UK, or for that matter many other countries similar videos could be made.
Sadly, now "The Torygraph" has found the youtube channel BHX will become the "wind capital" of the UK.
Quote:
"It's not the cross wind that's the problem, it's the associated turbulence."
Agreed, Bergerie 1, and ZeBedie is right: the surface winds cannot possibly be judged from the video. In any case, the wind reported by ATC to an a/c on very-short finals is not going to be mirrored over the runway threshold.
The other problem with these smaller, non-jet a/c is that their relatively low approach speed results in a very high drift-angle for a given crosswind component. So de-crabbing before touchdown is a big deal. It's 45 years since I flew high-winged turboprops, but the standard crosswind technique in my day - and we got plenty of practice in the Channel Islands - was the sideslip. (For the non-pilots, the upwind wing is lowered, using aileron, while opposite rudder is applied to stop the a/c from turning. The object then is to adjust the amount of bank and rudder so as to have the a/c pointing straight at the runway, without crabbing in the crosswind. This means that there is little or no drift to correct before touchdown, and the high wing allows you to land the upwind main-wheels first without risk of striking the propeller blades or wingtip on the runway.) The sideslip could be established well before the airfield boundary. Apart from anything else, it avoided the runway being partly obscured by the windshield frame - particularly useful in rain.
In the video, the crosswind is from the left of the runway. None of the a/c has lowered its left wing before touchdown, and some seem to have suffered a gust-induced roll to the right in the final stages. They all touchdown with a considerable amount of drift on a dry runway, and in one case well downwind of the centreline. Sorry to say it, but the six "P"s come to mind...
"It's not the cross wind that's the problem, it's the associated turbulence."
Agreed, Bergerie 1, and ZeBedie is right: the surface winds cannot possibly be judged from the video. In any case, the wind reported by ATC to an a/c on very-short finals is not going to be mirrored over the runway threshold.
The other problem with these smaller, non-jet a/c is that their relatively low approach speed results in a very high drift-angle for a given crosswind component. So de-crabbing before touchdown is a big deal. It's 45 years since I flew high-winged turboprops, but the standard crosswind technique in my day - and we got plenty of practice in the Channel Islands - was the sideslip. (For the non-pilots, the upwind wing is lowered, using aileron, while opposite rudder is applied to stop the a/c from turning. The object then is to adjust the amount of bank and rudder so as to have the a/c pointing straight at the runway, without crabbing in the crosswind. This means that there is little or no drift to correct before touchdown, and the high wing allows you to land the upwind main-wheels first without risk of striking the propeller blades or wingtip on the runway.) The sideslip could be established well before the airfield boundary. Apart from anything else, it avoided the runway being partly obscured by the windshield frame - particularly useful in rain.
In the video, the crosswind is from the left of the runway. None of the a/c has lowered its left wing before touchdown, and some seem to have suffered a gust-induced roll to the right in the final stages. They all touchdown with a considerable amount of drift on a dry runway, and in one case well downwind of the centreline. Sorry to say it, but the six "P"s come to mind...
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C.S: Ah, at last an old schooler. I used to do that on B757/767. Nice long undercarriage; it stopped the a/c shaking itself like a wet dog on roll out. Worked like a treat. No dramas. Nowadays, B738, not taught, even though FCTM has it as a valid technique, with limitations. Indeed there are 3 x-wind techniques, but often airlines choose to have an SOP for only one technique. How daft is that? Let's limit our crews to only one of the available techniques to handle a problem. When mother nature puts you up against it I would like to have confidence in my ability to choose & use all the options.
Quote from Cough:
"To make the point - Your beautifully described wing down technique isn't approved on many types."
True. Not on the B707 or DC-8 (particularly not on the CFM-engined variants), and presumably not on the B747, A340 or A380. In fact, in my experience the nearest you can get to the sideslip technique on any big jet is the "wing-down" technique, which is normally done just before the flare/de-crab.
If you have knowledge of the Q400 or any other a/c in the video, please share it with us.
Quote:
"Always use the AFM technique!"
Yes, although there may be more than one.
"To make the point - Your beautifully described wing down technique isn't approved on many types."
True. Not on the B707 or DC-8 (particularly not on the CFM-engined variants), and presumably not on the B747, A340 or A380. In fact, in my experience the nearest you can get to the sideslip technique on any big jet is the "wing-down" technique, which is normally done just before the flare/de-crab.
If you have knowledge of the Q400 or any other a/c in the video, please share it with us.
Quote:
"Always use the AFM technique!"
Yes, although there may be more than one.
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We dont know for certain that the limits were broken in this case but it looks like it from the pictures.
The notion that a Captain would, in order to land at a destination and not an alternate, deliberately flout X-wind limitations, thereby risking his life, crew lives and passenger lives, to say nothing of losing his job for irresponsible command decisions, and/or damaging an aircraft, is ridiculous.
If you haven't a clue it's best to remain quiet.
We dont know for certain that the limits were broken in this case but it looks like it from the pictures.
For these reasons and others a 'one limit for all' approach does not work and some discretion is generally permitted according to conditions, aircraft configuration, experience level of the handling pilot, operator procedures, etc.
A good paper issued by the Dutch NLR refers:
http://www.nlr-atsi.nl/downloads/cro...affect-you.pdf
At the end of the day, however, there is no substitute for pilot experience and skill, along with a little local knowledge.
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Indeed.
Firstly my apologies to those whose feathers I ruffled above with some rather poor wording of what I meant to say.
The mass of the aircraft and the approach speed both have a major influence.
The DHC6 Twotter taught me to limit my enthusiasm by taking a little trip into the weeds whilst landing at a typical african dirt strip. No damage to anything other than pride but I learned about gusting crosswinds and their effect on low speed directional stability. After that a quick look at the angles involved coming over the fence was a lot more likely to have me grabbing the ape hangers to go around. Discretion is the better part of valour.
Nobody is paying you to be a hero and scareing the passengers is not good for your career.
.
Firstly my apologies to those whose feathers I ruffled above with some rather poor wording of what I meant to say.
The mass of the aircraft and the approach speed both have a major influence.
The DHC6 Twotter taught me to limit my enthusiasm by taking a little trip into the weeds whilst landing at a typical african dirt strip. No damage to anything other than pride but I learned about gusting crosswinds and their effect on low speed directional stability. After that a quick look at the angles involved coming over the fence was a lot more likely to have me grabbing the ape hangers to go around. Discretion is the better part of valour.
Nobody is paying you to be a hero and scareing the passengers is not good for your career.
.
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What limits?
The aircraft I have flown, while some time ago, all had crosswinds mentioned in the manuals as "Maximum Demonstrated Crosswind". My airline read that just as it was printed. That the most crosswind they could find when flight testing the aircraft was listed as the "Maximum Demonstrated Crosswind". We did not read this to mean that we were limited to this value. We started the approach and landing and if all looked well it was completed and if not we went around.
There were airlines that had company policy that used the demonstrated max crosswind as an aircraft limit but not all did.
There were airlines that had company policy that used the demonstrated max crosswind as an aircraft limit but not all did.