[jhb_airlines] Re: FSX Official Add-On Acceleration

  • From: "Fred Stopforth" <fredstopforth@xxxxxxxxxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Wed, 7 Nov 2007 17:41:41 -0000

You could've drifted on.Being a newbie I feel like the little kid listening to the old mariner giving stories of experience and tales.Quite a few have come out from the group this week. Fred ----- Original Message ----- From: "bones" <bones@xxxxxxx>

To: <jhb_airlines@xxxxxxxxxxxxx>
Sent: Wednesday, November 07, 2007 3:28 PM
Subject: [jhb_airlines] Re: FSX Official Add-On Acceleration


I'm sure the British Legion could afford a couple of spike sticks.. <vbg>
Respect seems to be a dying trait in people these days.

Flying a 3.5 degree approach does indeed look wrong because you are higher
and see the runway in a slightly more plan view than a 3 degree approach.
This goes against the visual clues you have developed over the years - which
allow you to fly a correct approach even at airfields without PAPI's. This
visual image of a runway - or approach lights - can trap the unwary though.

If a runway has a marked upslope or downslope pilots tend to fly the
approach using their normal mental picture. The result (proved in tests) is
that if you are landing on a runway with a marked upslope the trend is for
pilots to get too low - and fly an approach too high for runways with a
downslope. This trend is more marked at night when local topography isn't
visible and runway lighting is the only visual clue.

VASI's and PAPI's help protect against the false clues if pilots trust them and ignore their gut feelings but it doesn't always work. Back in the 1960's
a Britannia going into an airfield in Yugoslavia (IIRC) with a marked
upslope on the main runway got too low and flew into a hill about 3nm out on the approach. In those days it was VASI systems only and the disadvantage of
these is that you get all reds if you are low but no indication as to
exactly how low you are. PAPI's are graduated over a much greater vertical
range. Anyway, it was a clear but dark night, there was no alarm raised by
the crew because they "felt" the approach was right and the next thing was
the props cutting into tree tops. Very sad.

Night flying brings other optical dangers to watch out for. Many airfields
are brightly lit but if away from urban areas the countryside around can be very dark. In some cases a departing aircraft will be climbing away and, as
the lights suddenly disappear from view, can give the pilot the impression
the aircraft has pitched up abruptly. The overwhelming instinct is to shove the nose down and can be so strong that it overrides the pilot's training to
scan the dials. This effect (known as the Black Hole Effect) was cited as
the probable cause of a 1-11 accident after investigators could find no
other rational cause for the accident. It was a UK accident but I can't
remember where or when.

A third night time optical illusion has come to light in recent years.
Aircraft making a visual approach at night to an airfield with little
lighting around it (usually airfields on the coast) have flown into the
ground (or sea) whilst on a curved base leg. In all cases the weather was
perfect with no cloud around - ideal for a visual approach but they were
also very dark nights. During the turn onto base leg the aircraft has the
runway in sight but is so far off the centreline that no PAPI indication is
possible - in other words the only clue to flying the approach is the
airfield and runway lighting. All seems to go well until the turn is made
and then the aircraft banks and also loses height until impact - the crew
not being aware that rapid height loss is happening.

The current theory is that visual clues are fine whilst straight and level -
aircraft seen to position and fly downwind without a problem. As the
aircraft enters the bank for base leg height perception seems to be lost and
it is during the turn that initial height loss occurs. This doesn't get
spotted because the crew are looking at the airport, aren't doing the usual
instrument scan (because it's a visual approach) and the descent is masked
in the turn by the increased G in a turn. In other words it is a phenomena
caused by a series of effects that fool the crews into thinking all is well.


The above isn't confined to any aircraft size. A Caravelle that flew into
the sea off Spain was likely the victim of this phenomena - the aircraft was
perfectly fine and the crew didn't react at all to the descent until a
fraction of a second before hitting the water. More recently a pair of 125's
flying into Stornoway on a very dark night had the airfield in sight from
about 50nm away. Both were visual with each other and both elected for
visual approaches. At some point, not seen by either ATC (no radar at EGPO) or the second aircraft the No1 aircraft flew into the sea. It was only when No2 aircraft called final that they realised something had gone badly wrong.

I think I'm drifting off topic a bit...

bones




-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Peter Dodds
Sent: 07 November 2007 13:57
To: jhb_airlines@xxxxxxxxxxxxx
Cc: pdodds@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: FSX Official Add-On Acceleration


but this guy split seven
neat cuts right next to each other to give the stone a faceted
appearance.
I had a wooden narrowboat for 16 years and the chap who did some work on it
was a really pleasnat guy and loved to talk and demonstrate the skills of
the old boatbuilders. The boat was caulked with oakum - the caulking irons
and mallet are beautiful objects in themselves - the mallet is such a
specialised shape, one wonders why.  He used to talk to me whilst caulking
the seams and his party trick was to feed the oakum into the seam, tapping
it gently into place them doubling back and feeding in another row until the
seam was "full", then hitting the caulking iron harder to consolidate the
oakum in the seam thus rendering the boat watertight. He could do an entire
run without ever looking at the point at which the mallet was striking, so
skilled was he at weighing the mass, inertia and trajectory unconsciously
within his mind.

Flint making must be a similar skill.

I was really chuffed recently when on approach into Southend, I remarked to my passenger, another PPL, that although the approach looked good, we had 4 reds on the PAPIs. He agreed, so I reduced the descent rate for a moment to
get 2 reds & 2 whites. I was convinced that we were too high then.  After
landing he checked in Pooleys to find that the Southend PAPIs are set at 3.5
degrees. So my brain instinctively could identify a difference of half a
degree in an approach slope. I must have learned /something/ about flying!
<g>

These examples illustrate the sort of intuition that no time and motion
system can ever capture, and why I hate so many of the modern  world's
practices. They have to do a risk assessment now for the British Legion to
march to church on the 11th November. They should just close the road. The
selfish B's who demand to drive past these old soldiers during their
memories should be sent to rot in the trenches!

Peter
I have now become a Grumpy Old Man - official.





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