"Airspace Compressibility"

Monday, February 7, 2005

Airspace Compressibility
Air Safety Week


Long-term predictions claim that air traffic will double over the next 20
years, in part due to the influx of light jets and the increase in air-
freighting. The creation of more flight levels by DRVSM (Domestic Reduced
Vertical Separation Minima) has not resolved an underlying problem.
According to one pilot cynic: "Explain to me how, by putting more aircraft
in the sky between, say LAX and PHX, that because of RVSM we will alleviate
the S turns, 90 degree turns off course and just plain holding that existed
before RVSM -- because of airport saturation? Bottom line is that in the
U.S., air traffic control (ATC) delays are because of airport saturation,
not airspace saturation. You can only fit so many airplanes on a runway.
Having more airplanes in the sky wanting to use that same runway is not
going to help." 

This pilot will be pleased to hear that NASA has been working on that. No,
we'll not need to leave the atmosphere or go suborbital. NASA has
successfully tested a new ATC computer program that will prevent
weather-induced traffic snarl-ups, arrival and departure bottle-necks and
put paid to holding patterns forever. It's called the Multi-center Traffic
Management Advisor (McTMA) and it can take onboard and smooth out all the
factors that would otherwise lead to a roundabout of the holding pattern
(flight plans, weather trends, real-time radar and ATC officer (ATCO) gut
instincts). Frequently, adjustments of just a few minutes at the point of
origin can alleviate airborne traffic jams at the destination. For more on
this, just "Google" McTMA. The acid test will be whether the software can
integrate with MIT's CDA (Continuous Descent Approach) software. That is
designed to allow a constant-power, non- stepped descent profile from a
closer-in descent point. It is claimed to reduce airport average noise
levels by between four and six decibels, save fuel and lower emissions. A
three-decibel difference is appreciably noticeable to the human ear while a
10-decibel reduction equates to 50 percent less noise. 

The safety concern is that experience has shown that ATC radars and comms
fail totally from time to time, as do the ATCO and pilot human error factors
in the airspacing equation. With increasing dependence upon automation and
computer-driven solutions, what brand of mayhem may be lurking in the
shadows when the over-full, aerially super-sized conveyor-belt system jams
up and comes unglued (as tends to happen from time to time)? At a time when
the FAA is beginning to panic over the departure rate of retiring seasoned
controllers, it's a question worth asking. Will there be a fall-back or just
a fall-over? However realistically, we'd need one of MIT's computer programs
for any sort of credible answer. It is doubtless one of those "suck it and
see" conundrums.


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