Lumpy conditions at LHR 29/7/08

[IainB]

This might seem a bit of a dumb query, but bear with me as a humble (though scientific) pax.

We had a smooth flight down to LHR from NCL on Tuesday morning until final approach when it all got very lumpy until our quite positive landing.

The return leg was even more fun with the plane appearing to deviate from the straight and narrow whilst hoofing up the runway to take-off speed. Once in the air, all was well and the flight proceeded without bothers.

Thanks to the crew for looking after us on both legs with their customary calm efficiency despite some pax sounding a bit arsey on the ground at Heathrow on the return. :D

My query is (after the rambling):

Was the weather - hot and humid - responsble for the fairly strange localised conditions at Heathrow or was it the usual alien activity at work in the nations capital?

:ok:

[WHBM]

Could be wake turbulence from a widebody preceding aircraft. Sometimes noticeable on a smooth day as you swing around onto long finals for Heathrow overhead Central London.

But hot and humid will do it as well when near to the ground. Do you ever fly in the tropics ?

[TopBunk]

Landed LHR Teusday late afternoon - there was quite a lot of thermal activity and a quite strong SSW airflow, with quite a few cumuliform clouds around.

Above the mixing zone it was calm, but at lower levels it was a little bumpy.

I can imagine that as the weather system had moved further east by the time I arrived, that earlier on in the day it may have been a little bumpier.

Nothing unusual though for a summers afternoon!

[IainB]

No, unless you count Miami as tropical, certainly couldn't taint NCL with that description..

Could understand why we were up and down a bit in the morning, but wasn't expecting it on the ground during take-off at about 1845hrs. We had a definite wandring tendency on the runway and was curious to know if anyone else had experienced similar on Tues.

Thanks for the words so far.

[Richard Le page]

The wandring on the runway is probably due to the wind not being directly down the runway. Pilots use opposite direction rudder to compensate the wind pulling the the aircraft across the runways and this gives the wandirng effect. Its particularly noticable when theres a strong crosswind and in tubroprops.
Pilots also make slight adjustments on the takeoff roll to avoid the runway centeline lights with the nosewheel to avoid a bumpy takeoff roll.
You also get this affect when landing in a strong crosswind .
Rudder is used again to keep the aircraft fron drifting off the runway and the effects can be quite severe.

I live in Guernsey and we get some severe crosswind conditions ,especially in winter and the aircraft that operate here ,mosty ATR and Dash8-Q400
coupled with our short runway make for some hairy takeoffs and landings.