Can some pilot please explain the answers to these conundrums, which have fascinated me over the years, more so after reading this interesting thread:
On the rare occasions when I am able to say "no ATC speed control" to someone on final approach it's more than evens that he will fly much faster than one of our "standard" speeds.
Why do so many 737s ask for 170kts to 4DME if some remarks on here are to be believed? I ALWAYS give them 170 now and adjust the spacing accordingly so am I doing something wrong? Not if one charmless pilot is to be believed - he was given 160kts recently and went bananas, even to the extent of moaning to the Tower man too.
Who was the BA pilot I met once who said he couldn't understand why we didn't always use 180 kts to 4DME to increase the landing rate? (In fact I believe that was being seriously considered as a standard procedure not too long ago).
I'm sure I've misunderstood the remark about 727s and the snitch box... I presume they actually wanted to fly much faster than our standard speeds? One crew flying a straight-in off LAM one morning doing 300kts+ asked what speed I wanted "No speed control" said I - so he said he'd keep "240 to the marker". In very, very recent times I've observed MD80s flying 280kts at 10DME and well over 200kts at 4DME.
As I think I've said elsewhere - ATCOs would love to sit back and do 5-6 mile spacing into Heathrow but it's YOUR employers who want us to thrash you guys in 2.5nm apart.
Lastly, I sympathise with you if the approach requires a lot of concentration but think about the final director - he doesn't just have to do it once; in one session he might land 50-60 of you guys and every single flight requires 110% concentration.