Jan
Two different beasts. A pop up flight plan will contain the same mandatory information as a pre-flight paper plan. For example, you will sometimes hear people returning from Europe and London info informing they cant find a FP. The pilot may then be asked to file an airborne plan. I agree this is time consuming and should be avoided if possible.
An airborne FP for class D transit is entirely different. The exchnage might go something like this:
G-XXXX requesting tansit,
G-XXXX pass your details,
G-XXXX requesting transit from X to Y at FL35
G-XXXX is cleared to enter controlled airspace at X, routing direct Y at FL35, squawk 5656.
You may of course be asked for your life history and many seem to offer this up anyway.
Anyway that is the airborne element of the FP, takes seconds, and even if you had pre-filed you end up giving much the same information.
Some would say if pre-filed FPs ever became mandatory for class D transits it would be a disaster and the recent actions of one or two Scottish airports has been described as a slippery slope (by me maybe
)
Why? Well some of us value the freedom to go where and when we like. If VFR I will often change my plans en route. The other day it seemed a pleasant idea as Gatwick wasnt busy to request a transit and a route over their threshold - which was happily granted.
Everything in life doesnt need to be controlled and IMHO shouldnt be. It is our airspace after all even if we have to pay to breathe the air it contains.
and to clarrify the earlier post a FP of the type I first described still needs to be closed on arrival, whereas a FP filed in flight as a class D transit request is closed by the class D unit when you leave class D and the closure will take the following form:
G-XXXX is now leaving controlled airspace, squawk 7000, and en route frequency.
G-XXXX thanks for the transit, squawk 7000 and en route.
Simples really.
(For brevity I have not included details of the service that will be provided in CAS etc which will be stated).
Oh and there is one little twist to this tale that might be worth mentioning. Occasionally two areas of class D airspace will join. Now you would have thought one would pass the transit details of a flight to the other as the flight isnt ever leaving class D. That doesnt necessarily always seem to happen so it is worth confirming with the first unit whether a handover will be given. For example G-XXXX will shortly be leaving your airspace, can you arrange a handover to Y. G-XXXX, Y has your details, retain your squawk, and say your call sign. G-XXXX, Y on handover, squawking 4545. G-XXXX, Y has your details, you are cleared to enter controlled airspace on your current heading at FL 35. You should not enter the new area of class D without a clearance, so somewhere in the exchange you should have been cleared to enter, or request the clearance, just dont assume that it has been given.