Old 5th Oct 2015, 22:34
  #652 (permalink)  
Lead Balloon
Join Date: Nov 2001
Location: Australia/India
Posts: 3,202

There is substantial and overwhelming evidence that pilots with CVD represent no greater risk to air safety than pilots without CVD. It's in the Pape and Dennison matters in the AAT, the subsequent safety record of pilots with CVD, the performance of pilots using NVG gear and the active policy of aircraft manufacturers and, in particular, avionics manufacturers in relation to systems design.

It's also between the lines of the O'Brien matter in the AAT, in the manifest intellectual dishonesty of the regulator's arguments.

The prejudice has its source in 19th century maritime navigation techniques, to which the accurate and reliable ability to perceive colours was and remains essential, at least during hours of darkness. Unfortunately, air navigation came after maritime navigation, and the former simply adopted the rules of the latter.

Today's rules of the air are essentially the 19th century rules of the sea. If you search the term "COLREGS" you will find the internationally-agreed codification of the rules of the sea and, if you're a pilot, they will look very familiar. Who gives way to whom, and what coloured lights have to be fitted where, and their meaning, are almost identical on the water as they are in the air.

But all of that stuff was left behind, literally, in aviation, when flying vessels started reaching speeds in the triple digit knots. That also left the CVD industry to cast about for evidence to substantiate its foregone conclusions, rather than revisit their validity in a different context. Citing the FedEx Tallahassee accident is an example.

These paragraphs from the NTSB report (here: http://asndata.aviation-safety.net/r...722_N497FE.pdf ) were quoted earlier in this thread:
The National Transportation Safety Board determines that the probable cause of the accident was the captain’s and first officer’s failure to establish and maintain a proper glidepath during the night visual approach to landing. Contributing to the accident was a combination of the captain’s and first officer’s fatigue, the captain’s and first officer’s failure to adhere to company flight procedures, the captain’s and flight engineer’s failure to monitor the approach, and the first officer’s color vision deficiency.
During postaccident interviews, all three pilots reported observing red and white lights on the PAPI display, consistent with normal PAPI operation. [Added note: the Flight Engineer was a qualified pilot on type. Hence the reference to “all three pilots”.] Although the flight engineer and captain reported seeing a pink PAPI signal on one of the four PAPI lights at some time during the approach, they also reported seeing red and/or white lights (which would have provided appropriate glidepath guidance) at the same time.

In postaccident statements, the flight crew and ground observers indicated that there were no obstructions to visibility along the approach path. However, the comments made by the first officer (“gonna lose the end of the runway”) and captain (“disappear a little”) suggest that they may have encountered a temporary obstruction to visibility (for example, clouds or mist) as they approached runway 9. If such an obstruction existed, it may also have obscured the PAPI lights. Although a temporary obstruction might help explain the flight crew’s failure to recognize the PAPI guidance while that obstruction was present, it does not explain why the three pilots failed to recognize the presence of four red PAPI lights throughout the rest of the approach. Further, according to FedEx procedures (and FAA regulations), if the approach end of the runway became obscured at any time during the visual approach, the pilots should have performed a go-around.
This is worth repeating: "[T]hree pilots failed to recognize the presence of four red PAPI lights throughout the rest of the approach."

I cannot fathom how any intellectually honest analysis of the circumstances described in that report and the findings of the report could be construed as substantial evidence of pilots with CVD being a greater risk to air safety than pilots without CVD.
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