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Darius
Topic Author
Posts: 139
Joined: Thu Jul 19, 2001 7:21 pm

Heavy Winds

Sun Oct 27, 2002 11:08 pm

Hi,

Today at AMS there is a storm:

FC271200 EHAM
TAF EHAM 271204Z 271322 24040G60KT 9999 SCT030 SCT040 TEMPO 1322 7000
-SHRA SCT020CB PROB40 TEMPO 1317 26048G72KT 4000 SHRA RA SCT012
BKN018CB BECMG 1416 26040G60KT BECMG 1618 29035G50KT BECMG 1821
29028G40KT=

Also a sigmet is out for severe low level turbulence below 3000ft.

Today flights are being cancelled, diverted and some are landing. Who decides if a flight is cancelled, the company or pilots? Are their any numbers in the book to make these decisions (e.g. a maximum accepted wind gust/direction as SOP for the company)? Obviously there is more risk involved with the wind than only the maximum crosswind allowed for the aircraft.
If in the air already, I suppose the PF makes the decision whether or not to attempt an approach or to divert directly, but based on what factors is this decision made? Is the "guts"of the pilot involved here?
In very gusty conditions my guess is that there is always a risk, even if the approach is stable and the wind blowing in the runway direction in such high winds.
What do your SOP's say about these situations?

I can imagine a pilot is facing a real difficult situation here. Any experiences to share?

For a PPL pilot it's a lot easier to make these decisions, because the stakes aren't that high. If the weather is approaching minimums, you just cancel your flight, no big deal.
However diverting and canceling do cost airlines a lot. As a pilot/company I can imagine you do not want to make this decision unless really necessary for safety reasons. Safety and efficiency is always a trade-off. Who defines the limits here?

Maybe a little vague, but I was just thinking what is on the minds of the pilots approaching AMS today.

Thanks for your insights.

 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Heavy Winds

Sun Oct 27, 2002 11:30 pm

I'm not an expert here but whenever Singapore expereinces a bad storm and if airfield is affected pilots always attempt to land once, twice or maybe thrice before giving up and divert to KL as advised by company. But even in the worst conditions most of them seem to make it down  Smile
Boeing747 万岁!
 
FLY 8
Posts: 330
Joined: Sat Dec 02, 2000 5:48 am

RE: Heavy Winds

Sun Oct 27, 2002 11:35 pm

I just came back from a flight to AMS!

I never saw something like that before. On the Walaround of the aircraft I lost my ID an some other stuff. Just flew away! There have been small stones flying across the apron like bullets.

never saw something like that!
yes i can handle that alone. - - -famous last words
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Heavy Winds

Mon Oct 28, 2002 12:21 am

Yeah those winds are pretty bad!
Boeing747 万岁!
 
AAR90
Posts: 3140
Joined: Fri Jan 21, 2000 11:51 am

RE: Heavy Winds

Mon Oct 28, 2002 2:19 am

>Who decides if a flight is cancelled, the company or pilots?

At AA, only "the company" may _cancel_ a flight. Individual pilots & dispatchers may (and regularly do) "delay" a flight indefinitely.

>Are their any numbers in the book to make these decisions (e.g. a maximum
>accepted wind gust/direction as SOP for the company)?

50 knots (either steady or gust) is the AA magic number. Above this number AA will suspend all flight operations at that airport.

>I suppose the PF makes the decision whether or not to attempt an approach or to divert directly,

The Captain is always responsible for his passengers, crew and aircraft.

>...but based on what factors is this decision made?

Knowledge and experience.

>Is the "guts"of the pilot involved here?

No. I'm paid to be a chicken and not risk passengers lives.... or my own.  Big thumbs up
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Heavy Winds

Mon Oct 28, 2002 2:42 am

>>>Who decides if a flight is cancelled, the company or pilots?

Let me preface my answer by noting that my answers are based upon US FAR Part 121 Domestic/Flag rules... Other Reg scenarios by other airlines in other countries might parallel US FARs, but may also vary greatly....

Under a US Part 121 Domestic/Flag scenario (including flights dispatched from the US to other international destinations) the PIC and dispatcher are jointly responsible for the safe conduct of the flight, including the operational control of the flight. If the weather forecasted for the destination airport required it, an alternate airport (and the fuel to reach it) would be called for, as well as fuel for holding, deviating around storms, along with other fuel for the appropriate contingencies, as well as reserve fuel.

Maximum wind limits vary among aircraft models, but generally speaking, many aircraft have a 30-knot crosswind limit on a dry runway. If the runway is wet, or the visibility is below 3/4 mile or RVR 4000, the max crosswind limit drops to 10 knots. If the runway has degraded braking action from snow, slush, water, etc., the crosswind limits could be down to 5-knots. All these limits are spelled out in the airline operator's manuals and Operations Specifications (Ops Specs), and compliance with them is required by FARs.

Should a crew be unable to land due to some parameter being out of limits (vis, wind, etc.) they will contact their dispatcher via radio (either voice, or text via ACARs) and advise them of their situation and fuel onboard. Some weather can be variable, i.e. thunderstorms move, foggy visibility may fluctuate up/down from one moment to the next, etc., so the PIC and dispatcher work out a mutually acceptable plan to hold down to X-amount of fuel and them proceed to their alternate. That alternate has to meet its own weather criteria, and may also consider where the particular airline has its own personnel and facilities (online) or somewhere else it doesn't (offline) but that may have better weather. Lots of other variables too.

If the weather situation shows no signs of improvement, flights can be, and are cancelled, and that's accomplished by the airline's dispatch office, usually management personnel. Should they say "go" when it's not safe to do so, the dispatcher and PIC have legal obligations not to operate, and they don't, since the dispatcher and PIC are the only two individuals who have signed the flight's dispatch release, and are subject to license action on FAR violations.



ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
si02y
Posts: 24
Joined: Wed Nov 14, 2001 1:05 pm

RE: Heavy Winds

Mon Oct 28, 2002 4:43 am

Hi Guys

Yes indeed, the last few days have seen extremely strong westerly winds that resulted in delays on flights heading west. Clocked 9V-SPE JFK-FRA SQ25 (24 Oct) and 9V-SMO FRA-SIN SQ325 (26 Oct) doing over 1104 km/h and 1116km/h ground speed respectively. The Airshow Flightpath display also showed that tail wind was in excess of 150km/h throughout the atlantic crossing and about 183km/h flying over Afganistan thru India at FL370.

Question: Are such strong winds normal for this time of year?
 
lmml 14/32
Posts: 2358
Joined: Tue Jan 30, 2001 2:27 am

RE: Heavy Winds

Mon Oct 28, 2002 7:53 pm

We landed in CGN last night in winds gusting up to 60KTS. We were severly thrown about. One serious gust below the 1000FT call out almost made us go around. But our pilot managed to keep the plane straight and continued the approach. Very interesting.

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