On Sun, 29 Feb 2004 17:17:16 -0500, JL Grasso
wrote:

On Sun, 29 Feb 2004 21:40:20 +0000, Pooh Bear
wrote:

JL Grasso wrote:

On Sun, 29 Feb 2004 18:03:00 +0000, Pooh Bear
wrote:

snip old stuff

There were also known and documented defects with various A320 systems at that time -
including throttle response and height indication. Capt Assiline asserts that the a/c
showed 100 ft altitude when it was actually flying much lower.

Anyone who would rely on a pressure altimeter to operate a low, slow
aircraft 100 feet from the ground when a radar altimiter was fucntioning
(and apparently giving accurate aural information) and available is not
making a prudent decision. The pressure altimiter (servo, ADC or
otherwise) is only required to be accurate to app +/- 30 feet at sea level
to begin with (and the DFDR was only required to show pressure altitude
resolution to +/- 100 ft, but may have been more on this unit). A radar
altimiter is accurate (depending on a given antenna/plane configuration)
to within 5 feet (and quite likely less) between wheel height and terrain.

Read the CVR transcript again and tell me how the Captain could possibly
be surprised later when told/shown he was below 100 feet during the
fly-over.

With delight. Sorry about the lost formatting when text posting

(French text is translated into English)

Time: Source: Contents:

12.44:27 TOWER QNH Habsheim 1012 Fox Echo 9.8.4
Captain OK

12.44:31 Co-pilot Roger

12.44:32 Captain 9.8.4 put in 9.8.4

12.44:34 Co-pilot 9.8.4 QFE selected!

12.44:37 Good gear is down; flaps 2!

12.44:42 Captain Flaps 3

12.44:45 Co-pilot Flaps 3!
Captain That's the airfield, you confirm?

12.44:48 Co-pilot Affirmative

12.44:51 Co-pilot You see it LL 01, when we get there you're at 1 nautical mile, that's right.

12.44:55 [GONG!] - nosewheel valve

12.45:04.7 GPWS [Too Low Terrain!]
Co-pilot OK!

12.45:19.1 Radio altimeter [Forty]

12.45:04.7 [GONG!] - GPWS cut off

12.45:05.7 Radio altimeter [Two hundred]

12.45.11 Co-pilot P.....G.....! (name of flight safety officer)

12.45:11.4 Radio altimeter [Two hundred]

12.45.12 Co-pilot G.. is going to ...eh!

12.45:14 Co-pilot OK, you're at 100ft there, watch, watch

12.45:13 Radio altimeter [One hundred]

12.45:19.1 Radio altimeter [Forty]

12.45:23.6 Radio altimeter [Fifty]

12.45:26 Captain OK ,I'm OK there, disconnect autothrottle

12.45:27.5 Radio altimeter [Forty]

12.45:32 Co-pilot Watch out for those pylons ahaead, eh. See them?

12.45:33 Co-pilot Yeah, yeah, don't worry.

12.45:34.5 [Clack! Clack! Clack!] - power lever dentents

12.45:35.3 Radio altimeter [Thirty]

12.45:36.2 Radio altimeter [Thirty]

12.45:37 Co-pilot TOGA/SRS

12.45:38.3 Radio altimeter [Thirty]

12.45:39 Captain Go around track

12.45:39.9 Captain Sh...!

12.45:41.5 END OF TAPE



NOTE

12.45:11.4 Radio altimeter [Two hundred]
12.45:13 Radio altimeter [One hundred]

that's a sudden sink rate of 4000 fpm as reported by the 'radio altimeter' whilst at around
100ft !

I assume that the second time is actually incorrect since it's out of sequence but I found the
same on another copy of the transcript.

Let's assume say it should be 12.45:15 ( more in lline with other timings ) - still indicates a
sudden sink @ around 1800 fpm !

So the radio altimeter was accurate ? I think not. And that was known to be one of the weak
spots in the A320's systems at that time IIRC.

I'm guessing that Capt Asseline realised that the radar altimeter was malfunctioning and
reverted to baro readings.


Regds, Graham

You need to know that at 12:45:11, the aircraft was still well off the
airport area by several thousand yards. They were over a hilly,
partially-forested area (Hardt Forest) to the right of the approach end of
runway 02 (which was the actual runway they were supposed to parallel
during the flyover). You should also know that radar altimeters report the
distance between the transceiver antennas and any objects below. So, if
the topography of the area below varies, or the altitude varies, the
readings change nearly immediately. Changes in the attitude of the
aircraft can sometimes have effects on the readings also. This is
something that an experienced Captain would know, and something a
planespotter would not.

If you would actually read something comprehensive concerning this
accident, you could see that the RadAlt was consistent while over the
relatively level terrain of the airfield - just as one would expect.

As in (as quoted by Pooh):

12.45:27.5 Radio altimeter [Forty]

12.45:35.3 Radio altimeter [Thirty]

12.45:36.2 Radio altimeter [Thirty]

12.45:37 Co-pilot TOGA/SRS

12.45:38.3 Radio altimeter [Thirty]


Phil
--
Pfft...english! Who needs that? I'm never going to England.
Homer J. Simpson