Scared of mid-airs

Jeff Crowell wrote:
You have been claiming that the speed of the USAF flight
was "480 knots (550 mph) at impact" (your post, 7/14),
when actual recorded speed at impact was 356 KCAS
per the accident report.

Larry Dighera wrote:
[That would be Message-ID:
]

AIB Report mentions the 480 knot closure speed twice:
AIB Report:
"The closure rate of Cessna 829 and Ninja 1 based on
radar-measured conflict alert data just prior to the collision was
approximately 480 KTAS."

"Based on their closure rate of approximately 480 knots," ...

With regard to your 356 KCAS airspeed at the time of impact, that is
not given as Ninja 2's speed in the AIB nor NTSB reports. Here's the
only reference to that number I was able to find in either document:

AIB Report:

"Ninja 1's displayed airspeed at the time of the midair was
356 KCAS" ...

You'll recall that Ninja 1 was not the aircraft that impacted the
Cessna. (I find the fact that the AIB report equates 'displayed
airspeed' with calibrated air speed a bit puzzling. Do F-16 airspeed
indicators actually display calibrated airspeed?)

I certainly grant the difference between Ninjas 1 and 2.
Don't you think that if Ninja 2 was flying form on Ninja 1,
their speeds must have been pretty close? And, I say again,
blithely using closure speed as speed of the mishap aircraft is
purposely deceptive.

As for KCAS versus KIAS in displays, I have no time in
F-16s, so I can't answer that categorically. But since
KCAS corrects for system error, it is more accurate than
KIAS, so why not? It would not surprise me if what's
displayed on the HUD, for example, and therefore
recorded by the tapes, is KCAS, since data displayed
there has been massaged by the aircraft's air data
computer (or some analogous system)...


So, lacking evidence to the contrary, I used the closing speed as the
speed at the time of impact. That may be incorrect, but lacking
better information, it seems reasonable to me, and not an exaggeration
nor hyperbole.

It doesn't strike you as even a little bit inflammatory in light
of your usage of that number? What the hey, you're only
off by 25%. Close enough, huh?


Per the F-16 Dash 1 he was allowed to be at 350 knots at
that altitude, and was traveling only slightly faster at the time
of the collision. What about that statement (from the
accident investigation) do you not understand?

Jeff, I understand that 450 knots within congested terminal airspace
is about one third faster than the 350 knot speed limit you state
above. One third is not 'slightly faster'. It is _significantly_
faster. (The 450 knot figure is quoted from the AIB report at the
beginning of this follow up article.) Perhaps you can provide the
reasoning you used in arriving at your conclusion.

Speed of the F-16 at impact was 356 KCAS.

Limiting the discussion to your 356 KCAS speed at the time of impact
figure disregards this fact:

Final NTSB Report MIA01FA028A:

http://www.ntsb.gov/NTSB/brief2.asp?...A028A &akey=1
"Speeds of up to 450 knots were noted during the descent."

Why would you overlook that 450 knot speed? Does the F-16 Dash 1 only
pertain to the speed at time of impact? :-)

Somewhere during the entire flight, Ninja 2's speed might
easily have been supersonic; would that have had any influence
on the collision? (other than the cosmic scheduling of it all--
obviously, anything which might have occurred to either F-16
or Cessna to speed or delay their movements throughout their
respective flights that day would have prevented this tragedy).
Seen that way, if Ninja had gone even a little faster then this
would have been nothing more than a close miss.

I never debated that Ninja flight recorded a speed of 450
knots during the flight. I'm simply saying that the speed
that really matters is the speed immediately prior to the
collision. I have not seen any claim other than yours that
Ninja was knocking down 450 knots within that critical
interval. And you are clearly selecting your data to put
your argument in the best possible light.

Similarly, the fact that closure rate was 480 knots of
course has meaning in terms of how much time was
available to both pilots to see and avoid. But to imply or
suggest that this is in any way the same as saying
that Ninja was making almost 500 knots at impact is a
blatant lie.


Jeff