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Old 15th Aug 2013, 18:38
  #149 (permalink)  
Join Date: Aug 2009
Location: Texas
Age: 60
Posts: 5,362
I fully understand the capabilities of radar data plots (which are even used in formal reports at times), but the sample rate is too low to support assumptions of accuracy without confirmation with the aircraft recorders.
Restated for emphasis.

I have now had a chance to review the approach plate.

IAF at COLIG is 14.1 DME, which is 12.8 nm from MAP. Min Alt 3500 ft.
FAF is BASKN, 6 DME, 4.7 nm from MAP. The 3.28 degree glide slope depicted (suggested) is IIRC based on the idealized slope from FAF to touchdown, however, I'd need to look that up to refresh my memory.

In the lower left hand corner, FAF to MAP times are 1:53 at 150 kts GS, and 1:34 at 180 kts GS. This would tell me, as a pilot, that if I were flying a CAT C or D aircraft on this approach, I should be configured, and on approach speed well before the FAF, and have my estimated ROD figured out before I hit the FAF. If I had a tool in the cockpit that allowed me to create a 3.28 glide slope that keeps me above min altitudes before FAF, all the better.

It looks as though the approach need ~700 fpm ROD if GS is 180, ~580-600 FPM ROD if GS is 150.

It will be interesting to learn the actual speed they were flying once that data becomes available from the NTSB.

Last edited by Lonewolf_50; 15th Aug 2013 at 18:41.
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