When Mode S was introduced, I wondered how long it would be before we had the first ‘
Why did you touch that button? event.
Operating in and out of LHR can be the most frustrating experience, those of us who have to do it often bear the scars. The issue of speed management on final approach is complex though, and we would be wise not to dismiss it lightly.
Finals 27R is not the M25, we don’t drop the clutch, shift up a gear and slow to 40 every time the cash-cow-cameras change their minds. Bear in mind that the aircraft in ‘
the tube’ are all different. Some are heavy, some light, some with GS mini function, some like the 757 might be doing 90kts inside 4, some have different high lift configuration, some need extra drag, some might need that last few moments of low drag to avoid a low fuel event.
Your mode S updates once a scan, and you might catch a 747 whilst he’s experiencing a 20kt gust. Because of inertia, the aircraft stays where it was whilst the ASI reads +20kts. That won’t happen on a 320, but his ASI will vary according to GS mini when managed speed is selected for landing.
If that sounds confusing, then good. It shows that this business is a panoply of operational problems and compromises. No-one operates in and out of Heathrow with intent to bust the limits. We try our very best to play the hand we’re dealt.
If the beancounters have just leant on you to pack ‘em in tighter, tell them from me to poke off.
If we wind the spring at LHR any tighter, someone’s going to get hurt.
