Colour vision is a bad example because it’s been allowed to place artificial barriers to people getting e.g. an IR
I’m not talking about the IR. I’m not even talking about day only restrictions. He had to mount a big fight to get any medical at all! Now contrast this to the AME “party line” of that they’re not there to prevent anyone from flying and that they are there to help, etc. It couldn’t be farther from the truth, could it?
I don’t think colour blindness is a particularly bad example, there are lots of stories of unreasonable barriers to getting a medical.
I took a printout from the optician to my AME and it was a complete non-issue
Nice for you, but I know many people, me included, where it wasn’t that easy.
hypoxia is another one that people don’t have good insight into
Again, any evidence for this? I find it hard to believe, after all the lecturing about hypoxia in subject 40. Furthermore, this forum IMO is enough evidence for the contrary.
I’m sure there’s a benefit to aviation medicine.
You are conveniently sidestepping the benefit of medicals. Sure, research (if done properly) and knowledge are a good thing. That doesn’t mean there’s any benefit to medicals.
It’s fashionable to look for an evidence-base for everything we do, but in practice there are questions that are hard to address for ethical or practical reasons
And rightly so. “Practicality” arguments are way too often used as an excuse to defend bad practice.
Providing evidence that medicals prevent accidents is therefore quite a ‘big ask’
But you still think it’s a good idea that everyone should be subject to onerous and expensive visits to the AME even though there is no evidence of any positive effect (or even the opposite)?
Another issue with CVD (colour blindness) is that the different methods produce very different results. I have a few links here (search the page for “colour”).
I almost totally fail the Isihara plates but got a 100% pass on the W-H Lantern test. And that is good for the rest of my life.
The tragic thing is that I have met people who failed the Isiharas and were never told by the AME of the other options.
Also I am certain that colour vision makes almost no difference to flying safety – as Pape demonstrated. I believe he got his ATPL reinstated but is limited to Australian airspace as his Class 1 medical is sub ICAO.
Also the vast majority of men who fail whatever CV test can see the really important colours fine. I can see all the colours “in life” except I merge grey and blue, which is relevant with clothing (and then only if you are discussing it with a woman 
) but AFAICS totally irrelevant to flying. Yet I fail 19 out of the 20 Isihara plates!
The stupid Isihara test is a test of subtle pattern recognition marked by deliberately confusing colour usage, not of colour vision. It costs almost nothing which is presumably why it is used as the first level of screening.
So many pilots were treated unjustly only 10 years ago… I could and did get the IMC Rating (and flew all over Europe “VFR”) but no IR. Then I learnt that the UK CAA was doing “under the table” daytime-only IRs to those who went there in person. I know one guy who got it but it was never offered to me. Now I know that they offer an IR to an audiogram fail pilot but again under the table. The process used is that EASA requires every case to be considered on its merits and this opens the door. The route previously possible for this was this – basically an FAA Class 1 and an FAA CPL and then you go to Gatwick, pay £300, and do an “ICAO Class 1 Renewal Medical” which gives you a UK Class 1 but with an annual hearing signoff which has to be done by an instructor within 3 months of the date of the medical (which basically means you do the class reval flight annually). I have no idea if the CAA still do the ICAO Class 1 route but it would never be discussed by email; only in person. A complete farce and it would be only on forums that one got to hear about it. One could get very bitter about the way the establishment closes up ranks.
The stupid Isihara test is a test of subtle pattern recognition marked by deliberately confusing colour usage, not of colour vision. It costs almost nothing which is presumably why it is used as the first level of screening.
The argument for the Ishihara test is as you say that it’s cheap. It’s also reasonably sensitive. It surely makes more sense to screen everybody with an Ishihara test and do an expensive and time-consuming test for those who fail it, than it does to do an expensive and time consuming test for everyone. It seems to me that where they screwed up is in not offering you the alternatives, not in using the Ishihara test as a first choice.
Part of the reason colour-vision defects went unnoticed for so long is that in everyday life people find other ways to identify colours. For example, for some people reds appear much darker than greens, which is fine when you’re looking at a red rug set out on the grass for a picnic. But not when you want to tell the difference between a green light which is far away and a red one that is closer with no other contextual information (e.g. against a black sky). There’s another useful phenomenon called visual popout where the eye is drawn towards colours that stand out – e.g. red beacons. So all in all it’s not obvious that you can extrapolate from abilities in everyday life to aviation.
Now contrast this to the AME “party line” of that they’re not there to prevent anyone from flying and that they are there to help, etc. It couldn’t be farther from the truth, could it?
My point was that you are (I believe) in a different jurisdiction and your experiences may not be applicable to a perhaps more permissive regime in a different country.
I would imagine there are AMEs out there who see it as their job to enable people to fly if at all reasonable. After all, many of them fly and are likely to have a more permissive attitude to risk than people who don’t fly. I’d argue that you would be more likely to find an AME with this attitude than a GP, and that it would be more practical to do so too (ask around, and you don’t need to change GP).
By the way, whether you go to see your GP or an AME, they’re working primarily for themselves, not you.
hypoxia is another one that people don’t have good insight into
What I’m getting at is that if you fly to an altitude where you become hypoxic you may not realise that you’re incapacitated. If you have a lung condition that altitude may be much lower than for other people. But what will it be? How predictable will it be? Does that depend on the lung condition you have or just the saturation values. Do you need an additional carbon monoxide check? I don’t know the answers to any of these things though I could perhaps look them up. But surely hypoxia 101 is that you often can’t tell when you’re hypoxic.
It’s fashionable to look for an evidence-base for everything we do, but in practice there are questions that are hard to address for ethical or practical reasonsAnd rightly so. “Practicality” arguments are way too often used as an excuse to defend bad practice.
Well, it’s right that we re-examine established practice. But how do you tell whether it’s actually bad practice if you can’t practically or ethically speaking do an experiment? Sometimes you have to fall back on working things out from first principles or doing what seems reasonable to someone with some experience in the field, or relying on evidence that is less strong than you would like. Unfortunately that’s going to favour those with (inevitably) entrenched interests because who else has a good take on whether what they’re doing is reasonable and proportionate? But we pilots who have to pay the AME tax to be told we can’t fly are hardly objective either. Perhaps AMEs frequently see ‘accidents waiting to happen’ (a category in which I include my hemianopic patient). Or perhaps they don’t believe in it all either. I’m not one. I don’t know. And it’s always interested me that AMEs don’t generally appear to contribute to threads such as this one.
Would you have allowed my hemianopic patient to drive, out of interest? Or would you have fallen back on Ionnidisian doubt of most medical evidence (which I share) and disregarded the weak evidence that it was safe?
But you still think it’s a good idea that everyone should be subject to onerous and expensive visits to the AME even though there is no evidence of any positive effect (or even the opposite)?
I certainly don’t believe everyone needs an AME. As I think I said at one point, I’d be more than happy to see pilots not carrying passengers excluded entirely.
In general I’m agnostic about them and have been all along. What I’m trying to do is point out inconsistencies in the arguments where I see them, or think about some of the wider issues e.g. access to advice, the inadvisability of assuming GPs will provide good aeromedical advice and readily take on the medicolegal risk of doing so. I am also genuinely a bit concerned about the prospect of dismantling a system that ensures there are doctors with some aviation medicine expertise distributed throughout the country.
I am also genuinely a bit concerned about the prospect of dismantling a system that ensures there are doctors with some aviation medicine expertise distributed throughout the country.
That would be a concern, but I’ve never seen that proposed.
But not when you want to tell the difference between a green light which is far away and a red one that is closer with no other contextual information (e.g. against a black sky).
True, though I would say that
As I said, I almost totally fail Isihara but you would have to live with me (as a woman ) for a year or more before you would realise my CVD exists at all.
That would be a concern, but I’ve never seen that proposed.
In the UK AMEs are as I understand it self-employed – paying handsome fees to the CAA for the privileges of being registered as such and having their premises inspected. Less business would inevitably mean fewer AMEs. I doubt we’ll ever get rid of AMEs for commercial pilots so there would always be some but I suspect you’d find some areas where they became very scarce on the ground.
Arguably, the time in flying when one needs to tell one colour from another is with distant lights e.g PAPIs and those colours are quite distinct, but colours are generally harder to tell when the light is coming from a very distant (small angle) source. For example how many people can see that the stars are all different colours? I never could. The only people I have met who can are all women.
I can see that Mars is reddish, and some of the stars may appear slightly bluer but I’ve never been sure of this. Through a telescope everything seems monochrome to me – Hubble’s false colour images causing great disappointment.
It’s hard to discriminate blue/yellow point sources as there are no S-cones (blue-cones) in the fovea but it is possible to discriminate red-green point sources – presumably why those colours were chosen for signal lights (plus the difficulty of making bright blue lights, particularly with filament lamps). Distant red/green strobe lights are much more strongly coloured than the stars and easy for most people to discriminate without thinking about it.
Whether not being able to do so represents a significant disability is a different question. I’m sympathetic to the view that it’s not.
My point was that you are (I believe) in a different jurisdiction and your experiences may not be applicable
Maybe, given that we’re more german than the germans, but given that it’s all Part-MED (or what it was called before) I doubt there is really that big of a difference.
I’d argue that you would be more likely to find an AME with this attitude than a GP, and that it would be more practical to do so too
Sure I could travel to Lampukistan, but calling that practical is a bit of a stretch. I actually did call around. But there aren’t that many AMEs to start with. There’s just one opthalmologist within around 100km. There are maybe a handful of AMEs within that distance. I even asked the air force medical branch, they’re likely still trying to coerce their SAP to tell them how much they’d have to charge me
By the way, whether you go to see your GP or an AME, they’re working primarily for themselves, not you.
That doesn’t seem to be factually correct. The AME is obliged to report everything to the authority. The GP has a duty of medical confidentiality. Furthermore, there is (fortunately) mounting financial pressure plus rating portals so that GPs no longer get away with abysmal customer service.
It’s funny you should say that, as an inability to see cherries was one of the first things that tipped people off to the existence of different forms of colour-vision:
On the flipside, there’s a theory that colours can be distracting and in jungle warfare colour anomalous soldiers were reportedly better at spotting the enemy.
In South America, lots of the monkeys have a form of colour vision where the males are all colour-blind but the females generally have colour vision…
