Jim L:
you are right about the MEL statement as a contradiction, it is a turn of phrase that has developed (incorrectly) to convey meaning quickly.
I share your thoughts on dispatch V operational decision. I believe we are way over prescribing the dispatch criteria and missing the outcome based decision making. The more we do this, the more we send ill-equipped pilots into difficult decisions without the experience and tools to choose correctly. The NVFR viz Vs visual references is a great example.
As the SC-196 convened over 10 years ago, I agree that it would be well worth while revisiting the standards established there. I seem to recall that you were on the pannel were you not?
To pick up on your field of view and diminished visual acuity comments, I am always suprised that others interpret these as significant disadvantages of NVG. The visual acuity of NVG (American Omnibus iv and better) is 20/30 and better. Omnibus vii is thought to be 20/20. Unaided viewing is 20/200 - somehwat less than the NVG!!!
FOV of NVG is around 40degrees. What is it from 500 ft with a nightsun? 2degrees??
FOV and Acuity only become an issue when you employ daytime flight techniques using NVG, like the military have to do to exploit the night time warfighting space. We actually do not vary much of our exisiting night techniques whilst using NVG so they represent an enormous increase in both FOV and acuity. For those who insist on comparing NVG to day time flight acuity and FOV as an example of how limited they are, then I agree: dont wear them during the day!
crab:
We carry paper maps, properly marked as a back up. We actually highlight the dangerous towers and wires directly onto our moving map system and therefore they standout much better than the paper versions. As sunnywa said, we would have to dust them off!
We do not transit below 500 ft on NVG and our weather has to be better than 5000m viz, and 1000ft cloud ceiling 2nm either side of track even to to go below LSALT. Accordingly, we do not face many of your issues, especially your map ones - which makes me even more suprised you dont have such a system as a mandatory item.
We only get into the wire environment during the take off and landing phases, thus we have very limited exposure. During the take off and landing, we employ mandatory use of white light and we approach from 500ft in a measured and controlled fashion clearing the path of wires using white light (and FLIR for those lucky enough).
For justification of moving maps and the garmin look no further than the lessons from the Norway crash as a substantiated safety case for their acquisition. Sadly for our industry however, we very rarely learn from the mistakes of others - it is almost as if we have to make them ourselves. Even then it is a long road.
How long ago did the UK CAA / AAIB publish the Strathclyde outcomes and recommendations???
sunnywa:
We have a CAR35 (Oz version of a "local" STC for you international ppruners)system that is not for primary nav. We use the twin Garmin 430W for primary nav.
We have two different mission profiles: rapid response and multi role. Our rapid response system will not go without a moving map as it is rarely safe to do so. We use the system not only to get to the exact accident site, but also to have a detailed look at the intended HLS before we arrive and get pressured into having to land, as well as having a system that does almost what yours does (though we are yet to recieve the "how many beers in the fridge" upgrade). We are working at putting a remote screen into the rear so they can see the pad as well rather than have to lean forward and look over the crewies shoulder.
The multirole missions can cope with the delays required of using the garmins coupled with a paper system, and we would (and do) go on that basis regardless of the moving map status.
We also use the systems to download wx trends and forecasts, radar pictures and cell trends along the intended track (though use the wx radar as primary nav) and even to submit flight plan ammendments or updates.
FLIR would be great, but we are also conscious of not having to have a 412 to do the job of a 117.
Last edited by helmet fire; 16th Jul 2009 at 02:50.