EasyJet, LTN and Fog.

[DeepC]

As a regular SLF on EasyJet on the LTN-AMS-LTN route I am quite interested in the technology that gets me up and down safely everytime. On Monday night I landed in very thick fog and the pilot came over the PA saying that we had landed on full Autoland. The visibility was absolutely horrendous so I was not suprised. When we pulled up on the stand there were no other Easyjet 737s to be seen. I remember a disclaimer that once appeared on the LTN website saying that the runway was equipped with full cat3? landing system but that the Easy 737s were not. Therefore Easyjet diverted flights during fog. Why was my monday night plane able to land then? (I was on G-EZYI). Can anyone post some insight into the capabilities of LTN and EZY, Ryanair, Monarch etc to continue operating in the fog which seems to plague LTN more than most.

[In trim]

I am not sure of the exact circumstances of your flight on Monday. However, the fog over the past few days has been, for much of the time, hovering right around our 'minimums'.

At a particular point on the descent (1000ft?), the tower will give the current RVR (Runway Visual Range) readings. If these are below the minimum, then the approach must be discontinued (go-around) at this point. You are not allowed to continue.

This is particularly frustrating in drifting fog because, sod's law, 60 seconds later (when you would have been at decision height), visibility may have increased to above our minima.

It is often a combination of good luck and good judgement which, in these marginal cases, allows a descent to continue when the aircraft immediately in front or behind you has had to go-around.

A challenging few days and a number of diversions.

In trim.

[ 12 December 2001: Message edited by: In trim ]

[ 12 December 2001: Message edited by: In trim ]

[Barnstomer]

D.C.
All easy 737 are able to undertake cat3a landings( 200m vis and 50' decision height) so landing in fog is ok as long as these minimum requirements are met.
On several occasions recently, the vis has dropped below this( have heard it down to under 75m) and as already stated, an approach cannot be legally made! Aircraft can be launched with the aim of landing at ltn if the forecast shows that the wx will improve, however this does not always happen.
Hence a diversion may occur if the extra fuel carried for low vis ops is used up. An event that is unpleasent and tedious for both pax and crews.

[EGGW]

Easy can only land to Cat3a minima 50'/200m rvr, whereas Monarch, Brits can land in 75m rvr, and the DH depends on type.
Should have boght Airbus Stellios
http://www.stopstart.fsnet.co.uk/smilie/biggrin3.gif

[DeepC]

Thanks for the replies. When we touched down visibility looked like it was a lot less than 200m. Does the 200m apply to the runway lighting or the actual runway surface? When we got onto the apron it was not possible to see the top of the tower only the red light on top of it. Good fun and the nervous wait to land in the fog shut up the loud, foul mouthed pax that tend to travel LTN-AMS-LTN.

Now for another question....

EZY 737s, have they all had the rudder modifications that overcome the problems with the damper malfunction. I was chatting to a pilot on one of the swiss easyjets and he said that they had, but a thread that I read on PPRUNE suggested that a lot of 737s worldwide have not.

[FlapsOne]

EGGW

It's not a Boeing vs Airbus thing, it's customer order plain and simple.

Maybe when/if Monarch and Brit start flying LTN-AMS-LTN then your comment might be relevant for the PAX on that route. :rolleyes:

[southern softy]

all rudder mods fitted, cat 3a, and the rule is if the minima is legal for the approach, once through the final approach fix the approach may be continued, even if the minima becomes worse, in drifting fog for example it can vary, the RVR dictates, not the vis, this is related to the approach lighting, and is better at night.

Childish post above mine unnecessary. ;)

[In trim]

D.C.
The minimums relate to Runway Visual Range and not standard visibility. RVR is the distance at which the approach lights can be seen.

Your comment re not being able to see the tower, but only the light on top, illustrates the difference perfectly.

In trim.

[JetMouse]

Interesting post this...

Can someone tell me how exactly is RVR measured?

[Brenoch]

In the old days they drove out to the end of the runway and counted the number of runway centre(or edge)lights visible.. Knowing the spacing between them they calculated the RVR.. Nowadays it´s mostly done by a transmissiometer.. As the name suggests this is a handy little photocell operated gadget that measures a section of air to se exactly how transparent the air itself is and is then converted into a relevant RVR figure..

[ 13 December 2001: Message edited by: Brenoch ]

[ 13 December 2001: Message edited by: Brenoch ]

[dot.con]

With regard to the 737 vs Airbus comments:

The 737 is not currently availabe with a Cat 3B option and I heard this was because no one had requested it as an option. Easyjet has now and there is a possibility that it may be available in the future.

RVR is measured electronically by a device that I cant even pretend to spell :D

Ok I'lll try - transmissometer

There are three of them next to the runway giving touchdown, midpoint and stop end RVR's. They are often not indicative of the visibility needed to land as the are not placed at the pilots eye postion but instead at a few feet above the ground. They are often affected by ground fog, such as on 23 at GLA where the waterway near the threshold can affect the transmissometer despite there being clear vis. ;)

Its an odd system!

.con

[Brenoch]

I was under the impression that for beeing certified to catIIIb one would have to have three completely separated autopilots whereas as far as i know the 737 only has two.. :confused:
And wouldn´t that also dictate the installation of a third hydraulic system on the 737 which I would imagine beeing a quite costy mod.. :D

Greatful for answers and I´m sure i´ll stand corrected..

[In trim]

There's still quite a lot of airports where RVR's are measured manually.....and because there need to be constant updates it means someone positioned out near the runway.

If you look at a lot of smaller airfields (Guernsey being one I am familiar with) there is a little fibreglass 'workers hut' alongside the runway. Some poor sod of a fireman gets to sit in this for hours on end, counting lights. How's that for job satisfaction? I knew I was in the wrong job!

In trim.

[fast cruiser]

Teeside is a good example of old fashioned
RVR calculations.

Trying to get in there the other day, they had vehicles at both ends of the runway counting the runway lights as the RVR inc or dec.

Maybe its time to come in line with the year 2001!!!

[backtrack27]

hey , old works

if it ain`t broken dont fix it , pity the fireman who has to follow this instruction

of course we all know that runway edge lights are 60 m apart

" we need an RVR of 1200m , so stay there and tell me when you can see 20 lights "

been known to take days sometimes !!

[NorthernSky]

The 'bus may cost more to buy, but it won't let your passenegers down the way the 73 will. Like the wise man who builds his castle on the rock, the operator who choses to use the airport on the hill with the fog, buys the 'bus. (Unless he can't see the point of having a schedule that runs on time - Oh, hang on, it doesn't, even on good days!)