Colour Vision in Aviation: Part 5
There have been several developments over the last weeks in the Colour Vision debate that I feel are worth reporting to AOPA readers. Hence, notwithstanding Part Four of this series, here comes Part Five.
There has been a deluge of letters and phone calls from pilots who suffer discrimination under the Department's colour vision policies.
The Department has indicated that it intends to rewrite ANO 47.3 (The Colour Vision Standard) and to have it in place before the date set for the hearing of my AAT appeal. It strikes me as farcical that ANO 47.3, the wording of which has remained unchanged for decades, should be suddenly rewritten with disgusting haste. There can be only one motive and that is to try to immobilize the case being fought in the AAT by myself against the Department. It appears, as I have stated repeatedly, that the Department has no concrete evidence to support its current colour vision policies. If I am wrong in that assertion, it would be most appropriate for the Department to await the outcome of my AAT appeal before hurrying into a rewrite of ANO 47.3.
In a similar vein, the Department has requested a postponement of the AA T hearing of my case. Thankfully, the AAT has denied the request. We are ready to proceed without delay and a postponement should not be necessary for the Department to prepare its case. If they aren't ready now, they never will be.
I have completed a study entitled "The Role of the Navigation Light System in Collision Avoidance". The paper looks at the design specifications of the navigation light system as laid down by ICAO and at the fundamental visual information for collision avoidance available to the pilot of a night flying aircraft. The navigation light system was inherited many years ago from the maritime system. It is demonstrably beyond doubt that the system cannot possibly work in the aviation environment, which is by definition three-dimensional. The visual cues to the task of recognizing collision risk are: the relative bearing and the rate of change of relative bearing; the distance to the other aircraft; and the rate of change of that distance (motion in depth). The paper has been circulated to a variety of parties, including the Department, for comment and will be presented at the Annual Conference of the Aviation Medical Society of Australia and New Zealand in Melbourne in September.
A fellow deuteranope, Mr Bob Pascoe, a senior lecturer in Computer Science at the Royal Melbourne
Institute of Technology, will be presenting a paper at the same conference on the principles of scientific inquiry. He will also demonstrate with a computer model of an aircraft, with its navigation lights installed as laid down in the ICAO specifications, that the navigation light system is inappropriate to the visual needs of the three-dimensional aviation environment.
It has been stated out by Professor Barry Cole that most pilots interviewed by him reported that they did not use the navigation light colour coding to achieve collision avoidance. When the fundamental requirements of visual collision avoidance are analysed, it is clear that the navigation light colour code is unusable by any pilot, irrespective of his colour vision status. It is therefore totally absurd to exclude any pilot from night flying on the basis of the colour coded navigation light system.
A study commissioned by the Department of Aviation in 1982 and conducted by Dr R. McKeIvey, looked into the value of colour codes used in various airport displays, such as runway, taxiway, terminal and approach guidance lighting. His conclusions were clearly that the colour components of these displays were redundant.
The use of the control tower signal lantern is rare, to say the least. Its system of coding is poorly understood by most pilots. The potential to confuse the green and the white signals has no operational significance. The likelihood of an airborne aircraft with radio failure being given a red signal at night is infinitesimally small. Exclusion from night flying of colour defectives cannot be justified on this basis. The introduction of electronic flight instruments ion poses no problem to the colour defective pilot since the colour components of these instruments are redundant, according to their manufacturers' advice.
Other sources are of the same opinion. Experiments commissioned by the Department to prove otherwise are scientifically invalid, for reasons that I am prepared to state in any forum. In any event, the issue of these instruments is irrelevant to the night flying case.
The issues raised by Dr Watkins in his letter (AOPA, June '87) are worth further comment. None of the technical objections put by Dr Watkins have any bearing on the case that I am fighting for Deuteranopes. The problems specific to the case for the Protan group arise from that group's peculiar loss of luminosity to red lights. Their problem is not so much one of colour confusion, but of reduced ability to see the red light at all, at certain ranges. No one has demonstrated that this loss of luminosity is necessarily operationally significant. Dr Watkins' last paragraph is most enlightening. I quote: "Finally, the great pity of the present situation is that it is entirely unnecessary. It is a relatively simple matter to design documents, aircraft and airports to eliminate or make redundant all colour coded information and to completely remove any need to consider colour vision at all. Unfortunately, I can see no signs of interest in doing this". I would say, "Here, here!!!" to those sentiments. I intend to carry this debate to that conclusion.
The colour defective pilot group has a legitimate right to have its grievances aired in such a way that all the evidence be brought forward and adjudicated by a body instituted for that very purpose (the AAT). To this end, the support given me by AOPA is entirely correct. I have been in constant touch with the AOPA Committee on the colour vision debate for close on ten years. The Department has had many opportunities to present its point of view in a public forum, but has always declined to do so. The support of AOPA has made it possible for me, a "David", with meagre financial resources, to take on "Goliath", with the seemingly unrestricted resources provided by the taxpayers of this land.
I consider it a very real danger that issues such as the colour vision debate, if left to the academics of our tertiary institutions, would simply go on into eternity. There comes a point where all the theoretical considerations must be tested against the practical task in hand. Theoretically, the colour deficient population should be wiping itself out on the roads. That this is not so is self-evident and requires a profound understanding of the defect in light of the practical requirements in complying with the rules of the road. The same is true of the aviation environment: The assumption has been quite wrongly held for decades that colour coding of information in the aviation environment is operationally significant. There is a mass of data now available that shows that this assumption is not valid. The assumed validity of the navigation light colour code was always wrong. To go on forever attempting to protect "the code", irrespective of the evidence, is to be REACTIONARY. This is exactly what the Department is guilty of. As a result, we see a bizarre scenario where all the Department's energies (at least with regard to colour vision) are being directed at stifling the public debate of the issue, instead of contributing positively. It may be good politics to rewrite ANO 47.3 under the present circumstances, but it won't make for good publicity.
Some readers may have seen a television program on the ABC called "THE INVESTIGATORS" on May26th. The subject was of colour "blindness” and a claim by an individual that he could "cure" the problem. Of interest was a statement attributed to the Department of Aviation that "The Department has access to information suggesting that people with colour vision defects have an increased risk of accidents". A little investigating by me has revealed that the Departmental source was in fact Dr A Zentner of the Aviation Medicine Branch. I believe there is no truth whatsoever in the statement and I would challenge Dr Zentner to publically divulge his source. My colour vision appeal was made known to the producers of "The Investigators" and they showed a lively interest in the issue. I, for one, would be happy to debate the colour vision in aviation issue with Dr Zentner on such a program.
The date for the hearing of my appeal is still the 17th of August. I would like to thank all those who have contributed to the fighting fund. All up donations have exceeded $2,000. The cost of conducting the case is quite a deal greater, however. I would like to think that the colour defective pilots, especially the deutan group, who stand to benefit from the case directly, might see fit to chip in for the costs. To be realistic, the protan group will not benefit immediately from my case. However, I predict that the entire colour vision issue will receive a long overdue shakeup following the AAT appeal. I am happy to assist any person presently restricted by the Department on the grounds of abnormal colour vision. It is essential that they firstly should obtain an accurate diagnosis of their deficiency.