9th Feb 2007, 10:43
Yesterday I was a passenger on an early morning flight from Gatwick to a European City and have a couple of questions and would appreciate the perspective from the professionals.
We boarded c7am, once all seated and doors closed the Capt informed us that due to the snow we had had a 60 minute delay for the de-icer to come and give us the once over.
My questions are:
1) As the south of England had 4 days notice of this weather coming couldn't the de-icing be done prior to loading the passangers?
2) The de-icer is basically a truck with a man spraying the aircraft from a gantry. I could see this truck doing one aircraft to another and finally coming to us. Could this activity be streamlined by moving the aircraft to the de-icers as part of the taxi run to the runway (sort of like a car wash)? i.e push back, taxi for de-ice then taxi to runway.
I'm sure that if you are in the profession there are blatantly obvious answers to these, but as a humble SLF, I'd appreciate my ignorance being alleivated.
9th Feb 2007, 11:17
Here's some info that hopefully answers your questions,
1) Although snow was predicted, the deicing fluid that's used most widely (Type II) has a holdover time of less than 45 minutes. If you deiced the aircraft, loaded the passengers you would need to deice the aircraft again.
2) The system you describe (Car Wash Style) is in use in airports in the US but not widely used. The method that was used on the aircraft that you were on is most popular as it can be done on stand, any stand. It is far more economical with fluid, and is more reliable, in that the person who is deicing can concentrate on areas that has more snow / ice than less covered areas.
Hope these answers help. If you would like me to elaborate more, please feel free to ask!!
9th Feb 2007, 11:34
Thanks for that. On point one, if I was to put on a commercial head for a moment......
Wouldn't it be in the airlines interest to pay for a "2-hour" fluid so that slots aren't missed and cancellations are avoided (and profits not dented too much).
I assume a 2-hour fluid exists, if not, it's back to chemistry lessons for me as I've found a potential gap in the market.
Again, thanks for the speedy response.
Sorry - does not exist :hmm:
If you could invent some then you would be a very wealthy SLF :D
14th Feb 2007, 10:25
The pilots may have missed their slot time and had to negotiate for another one which was an hour later. With the need to de-ice coupled with a slot time the guys have to figure out when to start push back because you don't want to bust your holdover time and have go back for a 2nd squirt thereby missing your slot time and have to renegotiate for yet another one. So now considerations are taxi time, traffic, position of the de-icing equiptment and any other time related factors you may have. From all these considerations you choose what you think is the best time to push back from the gate so that you 1. dont bust your holdover time after being de-iced and 2. maintain your slot time. Places like Moscow will de-ice you after you push back and then you have to taxi to the runway for the takeoff (possibly in a long queue) whereas in Amsterdam they de-ice you near the holding point of the runway so you can immediately take off.
14th Feb 2007, 21:04
One other consideration is that the airport may only allow de-icing to be performed in certain areas due to the drainage system. In nearly all main UK airports the drainage system on the stands takes away all the waste fluid to be filtered and processed so harmful waste is not realised into the surrounding environment.
Additionally it was always argued that as severe weather was only a rare occurance it was not worth the additional cost of building/maintaining de-icig areas around the holding point, and that the very days of disruption caused was acceptable.
14th Feb 2007, 22:49
Speaking of these... how rare is rare? I mean in winter, how many days can one expect to have tp De-ice?