Concorde-landing procedures

From:         fxm4993@hertz.njit.edu (Farhan Muhammad)
Organization: New Jersey Institute of Technology, Newark, N.J.
Date:         02 Dec 92 03:49:46 PST
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	Landing approach of Concord.
	---------------------------

 Excerpt from the book "Flying Concorde".

'200 feet.'

  The flight engineer, who cannot see the runway since he is behind and
a little below the pilots, is reading the radio altimeters which are
bouncing signals off the groiund to determine height to within a foot.
 
  '100 feet ...
  '50, 40, 30, 20, 15.'

  At 40 feet the autothrottles are disconnected by pressing a small button
on either side of the levers.  A slight backward movement of the stick
slows the rate of descent a little, pitching up perhaps a degree, from
10.5 to 11.5 degrees.  The pilot's eye is still 75 feet above the runway
(about the same height as a 747 pilot's) and he aims at a point about
2000 feet down the runway, knowing that the main wheels, trailing below
and behind, will arrive well before that point.

  From about 100-feet altitude we have been about to hear the 'ground effect'
starting.  A large wing, approaching the ground, begins at some point to 
squeeze the air between it and the surface, settling into a cushion of its own
making.  The large wing area and the high angle of attack make this effect
more pronounced on Concorde than on conventional swept-wing aircraft, and
seems to throw back some of the noise of air rushing into the engines.
That is what it sounds like, at any rate.

  At fifteen feet, the throttles are closed.  The immediate effect is 
a tendency for the nose to drop.  Landing is largely a matter of countering
this tendency as the aeroplane settles into its ground effect.  A slow
backward movement of the stick keeps the nose where it is.  The rate of 
movement depends on the strength of the pitch-down tendency.  Good landings
are simply a question of getting the balance right, so that the nose stays
rock-steady against the far end of the runway.

  Once on the ground there is a second landing to perform- the nosewheel
is still a long way in the air.  A nudge forward with the stick to get it
on its way, followed by a backward movement to cushion its descent, and
all the wheels have arrived.

  As soon as the main wheels are on the ground, reverse thrust is engaged.
Once the nosewheel is on, power is increased in reverse to kill the speed.
At this point the stick is pushed fully forward to keep the nosewheel on
the ground, as the low-slung engines, producing their reverse thrust below
the body line, would tend to raise it again if allowed.

  The elevons are still effective, though, and the nosewheel is kept firmly
on the runway as braking starts.  The powerful carbon discs get to work, the
speed reduces, and the runway, which on touchdown didn't seem as long as it
shuold be, with the eye still 35 feet in the air, lengthens again to its
proper shape.

  '100 knots.'
  The two outboard throttles are pushed into reverse idle.
  '75 knots.'
  The inner follow.
  '40 knots.'

  All the engines are returned to forward idle power and the aeroplane
is nearly ready to be turned off.  It is easy, in any aeroplane, to think
that the speed just after landing is lower than it really is, so a glance at
the INS groundspeed is useful here.

  Once we have turned off the runway, he nose is raised to the 5-degree
position again, and the two inboard engines are shut down (at this weight,
at the end of a flight, two engines provide quite enough power for taxiing).

  From runway 31 Left it is a longish taxi round to the British Airways
terminal on the other side of the circle of airport buildings.  As we
approach it the time is a few minutes after 3.00 pm in London.  Here, in
New York, we are nearing out scheduled arrival time of 10.15 - apparently
an hour before we left our gate at Heathrow.  Just under four hours, gate 
to gate: an hour less than it takes the earth to rotate through the
angular distance separating London and New York.  Three and a half hours'
flight-time to cover three and half thousand miles - an average speed
of a thousand miles an hour.

  Some of the disembarking passengers show signs of excitement - it has
been their first supersonic flight, and it will be a while before they have
sorted out the mixture of unreality and normality they have experienced. 
Others, the majority now, take it all for granted - they have probably
used Concorde several times.  And it has been normal.  So it should be
by now; but this normality had to be present from the first flight, in
January 1976, and that took a little doing.