Since this is about flaps, perhaps someone can comment on this.
On 29th April at around 18:20, leaving Heathrow and passing the west end of 27L on M25, I saw a Cathay Pacific 744 take off with what appeared to be full flaps. I assume this from the amount of sky that could be seen between the large flap extensions and the wing. The wind was quite strong and very gusty but it still surprised me. He was following the same path as many others previously taking off. Perhaps he was going around but as others were landing on 27R and taking off on 27L, that might have been just as unusual.
Any comments? Is it ever necessary to take off with large amounts of flap?