Comair Plane Carshes At Lexington

In article .com,
"Cassie" wrote:

I read that it took off at 6:07 a.m.

Pay no attention to Charles. He literally lives in a flight simulator
world, and doesn't care to understand how things work in the *real*
world.

Robert Cohen wrote:
So, the momentum took the plane to the point where it went completely
down.

I presume it got-off-into-the air for a few seconds.

There are many possibilities.

Consider the pilots would have made all their calculations on the
various speeds based on the long runway. By the time they realised that
the runway was too short, they would already be going too fast to abort
takeoff and stop before end of runway.

http://www.crj.bombardier.com/CRJ/en...d=en&crjId=200
Lists the flying skidoo as requiring 5800 feet to take off. But at
maximum *landing* weight only, it needs 4800 feet to take off.


What is not known is what the real runway distance is *really* needed
to get to V2. (and one would have to calculate this precisely for that
particular aircraft's weight for that specific flight).

They say there were 47 passengers. (plus 3 crew members). So not quite
full, but close. (and I don't know how much fuel they would have
loaded). And one would have to consider also air density/temperature
to know the exact airspeed it would have had to have to remain in the
air. (on cold days, you require less airspeed to remain in the air).

I have not seen aerial views if the site yet, so it is clear how much of
the distance between end of runway and final resting place was travelled
on the ground.


Have the media indicated any damage to end-of-runway equipment ? Or is
there reasonable certainty that the aircraft actually lifted off and
then fell back down ?

Note that in the case of the AC flying skidoos at Fredericton, there
were some issues with the flight director telling the pilot he could
climb faster than he should have for that particular situation. But in
that case, the (inexperienced) pilot wasn't aware that he didn't have
enough energy to climb and blindly followed what some screen told him he
could do which lead to a stall that brouight the aircraft down to travel
on the snow in the forest.

In this Comair accident, the pilots would have realised they were in a
very dangerous situation when they saw the premature end of the runway
approach quickly, and would have known their energy situation wasn't
sufficient for a normal takeoff. On the other hand, they probably had no
choice but to raise the nose enough to force a take off, at least to
skip over the fences at end of runway.

If, as soon as in the air, they lowered the nose to prevent stall and
allow aircraft to pickup sufficient speed again, they may have hit
trees. If they didn't lower the nose and tried to fly with insufficient
speed, they may have stalled and fallen down.


What has not been discussed yet are survivability issues.

It appears that the wings were clipped off before the aircraft came to a
stop in its final resting place. One would think that this would have
slowed down the aircraft significantly. How come none of the passengers
survived ? The CRJ is a pretty confined aircraft and it isn't clear
that it would be an easy egress before fire/smoke would knock people unconscious.

(VS) wrote in
:

In article .com,
Robert Cohen wrote:

The airport's 7,000 feet runway should have been utilized for the
takeoff. But the 3,500 feet runway was apparently mistakenly utilized.

It was apparently dark, perhaps the number "22" runway was mistakened
for the number "26" runway, and thus apparently the cause was the
take-off from the shorter runway.

If you look at the airport diagram:

http://204.108.4.16/d-tpp/0608/00697AD.PDF

both runways start from the same taxiway and are quite close to each
other. It be would easy to confuse them at 6am, although they should
have recognized that something is wrong - 26 is much narrower, doesn't
have the usual markings and its runway lights were out of service.

On the other hand, even much more experienced pilots sometimes mistake
taxiways for runways and whatnot. Didn't a KAL 747 take off from
a taxiway in ANC a few years ago, plowing through a snow berm along
the way? Of course, this is KAL, where pilots don't necessarily speak
English and tend to ignore whatever the tower is prattling about.



A quick glance at his compass would have told him he was on the wrong
runway. The runway numbers normally correspond to the runway heading
rounded to the nearest 10 degrees and the trailing "0" deleted. For RWY
26, the compass should have been close to 260, not 220 as it would read for
RWY 22.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

In article ,
Marty Shapiro wrote:

A quick glance at his compass would have told him he was on the wrong
runway. The runway numbers normally correspond to the runway heading
rounded to the nearest 10 degrees and the trailing "0" deleted. For RWY
26, the compass should have been close to 260, not 220 as it would read for
RWY 22.

There are many different clues that should've told them they are on
the wrong runway. A compass is no good if the person looking at it
is not paying attention.

In my own flying, it certainly happened once or twice that I taxied to
the wrong runway, in the dark, at an unfamiliar airport. Of course,
I didn't have 47 paying passengers behind me.

(VS) wrote:

both runways start from the same taxiway and are quite close to each
other. It be would easy to confuse them at 6am, although they should
have recognized that something is wrong - 26 is much narrower, doesn't
have the usual markings and its runway lights were out of service.

There is some question about the lights. NBC news suggested that the
center lights might actually have been on.

Au le contraire, monsieur: This flight wasi scheduled to leave
Lexington Blue Grass circa 6 something and arrive at
Hartsfield-Jackson circa 7:18 AM.

I think Lexington is on Eastern Daylight Time and I know Atlanta is.

I've heard a couple of other allegations/factors/insights on tv by a
commentator-pilot the local tv station has apparently employed to
consult:

The runway lights were not working.for at least one of the two runways.

There has been an asphalt re-surfacing project, either recently
completed or on-going of the runway(s).

It seems to be a tragic combination: the darkness, lacking in runway
lighting, confusion from the resurfacing





Charles Newman wrote:
"Robert Cohen" wrote in message
oups.com...
My own observation/speculation/perception that is based on from what
I've heard on tv so far:

At six o'clock this morning it was seemingly dark outside in my area
near Atlanta.

I presume it was seemingly slightly darker at the Lexington airport,
where there are two runways.

The airport's 7,000 feet runway should have been utilized for the
takeoff.

But the 3,500 feet runway was apparently mistakenly utilized.

It was apparently dark, perhaps the number "22" runway was mistakened
for the number "26" runway, and thus apparently the cause was the
take-off from the shorter runway.

It would be mid-morning at take-off. According to the
schedules I have, that wold be Comair flight 4971 on a
Canadair CRJ, scheduled for departture at 8:45AM
and arrival in Atlanta, at 9:55 AM. It obviously
would not be dark at 8:45.

In article ,
James Robinson wrote:

both runways start from the same taxiway and are quite close to each
other. It be would easy to confuse them at 6am, although they should
have recognized that something is wrong - 26 is much narrower, doesn't
have the usual markings and its runway lights were out of service.

There is some question about the lights. NBC news suggested that the
center lights might actually have been on.

According to airnav (http://www.airnav.com/airport/KLEX), there are no
centerline lights on the 8/26 runway. Only MIRL (runway edge lights)
and REIL (runway end), and both are out of service.

Interesting, coherent thinking about what the pilot(s) were confronted
with.

B-t-w: An off-duty pilot was apparently sitting in the jump seat too..

nobody wrote:
Robert Cohen wrote:
So, the momentum took the plane to the point where it went completely
down.

I presume it got-off-into-the air for a few seconds.

There are many possibilities.

Consider the pilots would have made all their calculations on the
various speeds based on the long runway. By the time they realised that
the runway was too short, they would already be going too fast to abort
takeoff and stop before end of runway.

http://www.crj.bombardier.com/CRJ/en...d=en&crjId=200
Lists the flying skidoo as requiring 5800 feet to take off. But at
maximum *landing* weight only, it needs 4800 feet to take off.


What is not known is what the real runway distance is *really* needed
to get to V2. (and one would have to calculate this precisely for that
particular aircraft's weight for that specific flight).

They say there were 47 passengers. (plus 3 crew members). So not quite
full, but close. (and I don't know how much fuel they would have
loaded). And one would have to consider also air density/temperature
to know the exact airspeed it would have had to have to remain in the
air. (on cold days, you require less airspeed to remain in the air).

I have not seen aerial views if the site yet, so it is clear how much of
the distance between end of runway and final resting place was travelled
on the ground.


Have the media indicated any damage to end-of-runway equipment ? Or is
there reasonable certainty that the aircraft actually lifted off and
then fell back down ?

Note that in the case of the AC flying skidoos at Fredericton, there
were some issues with the flight director telling the pilot he could
climb faster than he should have for that particular situation. But in
that case, the (inexperienced) pilot wasn't aware that he didn't have
enough energy to climb and blindly followed what some screen told him he
could do which lead to a stall that brouight the aircraft down to travel
on the snow in the forest.

In this Comair accident, the pilots would have realised they were in a
very dangerous situation when they saw the premature end of the runway
approach quickly, and would have known their energy situation wasn't
sufficient for a normal takeoff. On the other hand, they probably had no
choice but to raise the nose enough to force a take off, at least to
skip over the fences at end of runway.

If, as soon as in the air, they lowered the nose to prevent stall and
allow aircraft to pickup sufficient speed again, they may have hit
trees. If they didn't lower the nose and tried to fly with insufficient
speed, they may have stalled and fallen down.


What has not been discussed yet are survivability issues.

It appears that the wings were clipped off before the aircraft came to a
stop in its final resting place. One would think that this would have
slowed down the aircraft significantly. How come none of the passengers
survived ? The CRJ is a pretty confined aircraft and it isn't clear
that it would be an easy egress before fire/smoke would knock people unconscious.

In article .com,
"Robert Cohen" wrote:

Interesting, coherent thinking about what the pilot(s) were confronted
with.

B-t-w: An off-duty pilot was apparently sitting in the jump seat too..

No, an off-duty pilot from another airline was "jumpseating," but was
not in the cockpit, thanks to TSA's new security rules. Had they not
made it so onerous for us to ride in each other's cockpits, maybe an
extra set of eyes would have caught the mistake and saved these lives.

"Beavis" wrote ...

"Robert Cohen" wrote:

Interesting, coherent thinking about what the pilot(s) were confronted
with.

B-t-w: An off-duty pilot was apparently sitting in the jump seat too..

No, an off-duty pilot from another airline was "jumpseating," but was
not in the cockpit, thanks to TSA's new security rules. Had they not
made it so onerous for us to ride in each other's cockpits, maybe an
extra set of eyes would have caught the mistake and saved these lives.

True I suppose, but then one presumes (a) there was someone in the tower,
(b) (s)he was being paid to look out the windows, and (c) (s)he might have
been there long enough to even by dawn's early light (and in Kaintuck) to
recognize that the aircraft had taxied to the apron of the wrong runway
(although the relative small 40% diffreence in the two axes might have made
a visual confusing, depending on the distance from the intersection to the
tower and the tower's location in relation to the runways).

TMO