Factoids

Sunday, October 24, 2010

Numbers Don’t Lie

The latest ‘nugget’ of information from the ‘Eco-Merge’ Central Texas Airport site is this bit of numerical numbskullery:

“As many as 250 aircraft are projected to be housed at CTA, but only a small percentage of those will be involved in daily takeoffs and landings. Eighty percent of daily air traffic will arrive from the more rural north, descending against the southern wind with the practical effect of minimizing noise. Takeoffs will quickly rise 1,000 feet or more before leaving GCC grounds and climb steadily from there.”

Let’s see now, the north end of the runway is less than one-half mile from FM 969, with existing homes and new home building going on about 100’ north of the Right-Of-Way of FM 969.

The south end of the runway is less than one-half mile from the Colorado River on whose banks are located the McKinney Roughs Nature Preserve and the Hyatt Regency recreational complex.

So, Mr. Carpenter is trying to tell us that a loaded 737 is going to take off and climb to 1000’ in 2500’?

That’s about a 22 degree rate of climb, and with the diverse performance envelopes of many types of aircraft, a COMPLETELY unsupportable claim.

Ever see any of those climb like that after a departure from ABIA going over Hwy 71?

I haven’t.

Remember, a 737 with Stage III engines will develop 115 dB of noise at 500’.

Now if you’ll notice ANOTHER antic with semantics which says that:

“As many as 250 aircraft are projected to be housed at CTA, but only a small percentage of those will be involved in daily takeoffs and landings.”

Did he say anything about large cargo-aircraft NOT housed at the CTA making up to 250 flights daily?

Nope.

Now that we’ve settled those bits of verbal sleights-of-hand, it’s time to address the FAA-mandated 3 degree approach slope for aircraft arrivals.

The MAXIMUM ALTITUDE for aircraft entering the five-mile approach-zone of either end of the runway is 1350’ above-ground-level (AGL).

Notice that I said MAXIMUM ALTITUDE.

They can be lower.

Much lower.

FAA rules mandate that aircraft only have to clear ground obstacles by 35’.

At the MAXIMUM approach altitudes, they’ll only be approximately 100’ AGL over many homes.

See a pattern here?

Numbers don’t lie.

I’ll leave it to the people of Bastrop County to figure out who is . . .

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