Night Vision Goggles (NVG discussions merged)
Flygunz, at the risk of opening myself up to some witheringly witty punch line yes I do, longboard and short - my best trick used to be a one-handed duck gybe but that was a few years ago when I was young and supple!
I have it on good authority the NG 700s come in 2 flavours, one with Gen 3 tubes which the military (certainly RAFSAR) use and one with Gen 2 tubes - the ones the N Wales police have chosen. Gen 3 tubes are not available for civilian use, presumably as a means of keeping military capability ahead of the rest. Similarly Gen 4 goggles which exist in America won't be sold to anyone but the US military to start with and will eventually percolate through to other armed forces - at this stage the Gen 3 technology will probably be made available to civvies.
I know that many police pilots are ex military (particularly AAC) and therefore have a good grounding in NVG ops but what training will be given to a civilian pilot flying for the police before he is allowed to use them? And what are the currency requirements for NVG use by civilian operators?
Flygunz - the only other person who windsurfed at MW was the DCFI unless my memory is completely addled!!!Dont use my profile email as it is out of date.
I know that many police pilots are ex military (particularly AAC) and therefore have a good grounding in NVG ops but what training will be given to a civilian pilot flying for the police before he is allowed to use them? And what are the currency requirements for NVG use by civilian operators?
Flygunz - the only other person who windsurfed at MW was the DCFI unless my memory is completely addled!!!Dont use my profile email as it is out of date.
Nvg
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HIIIIIIIIIIIIIIIIIIIII
Ifound this site interesting
www.morovision.com
click on how night vision work
Ifound this site interesting
www.morovision.com
click on how night vision work
Last edited by ab139heli; 15th Aug 2002 at 18:08.
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Just as my disclaimer....None of this information is classified - and is readily available from other sources.
NVG (Night vision goggles) is commonly used to describe light amplification goggles or image intensifiers. The goggles typically mount on a bracket from a helmet, like a set of binoculars. The goggles operate by taking in an ambient light image and amplifying it agaist a green phosphor screen inside the binocular. The result is that with very minimal light (eg, even starlight coming through cloud layer on a moonless night) you have enough light to see. This differs from FLIR which uses the heat from objects. NVG has a bit of that - since it covers part of that spectrum, but it is really using extremely low levels of natural light reflected off objects, rather than heat emitted from an object.
The original goggles used in aviation (late 70s early 80s) were Gen-II goggles and amplied the entire visible spectrum and then some. This required that cockpit and instrument lighting be dimmed so much that it was not visible to the naked eye. It also required the pilot to continually shift focus in and out of the cockpit - which the Army found to be a good way to kill pilots.
Gen III goggles only amplify light in the red and infra-red end of the spectrum. Actually the spectrum is optimized for starlight reflected off vegitation. By only amplifying this portion of the spectrum, the cockpit can use the other part for its lighting without disturbing the goggles. Gen-III goggles mount slightly off the helmet and are focused for outside viewing. The pilot looks below and past the goggles to view cockpit instruments without looking through the goggles.
We typically talk about Class A and Class B goggles. The difference is defined in MIL-L-85762A which is the controlling spec for this technology, and for the cockpit lighting. Class A goggles have a 625 nm wavelength cut-off which means everything in the cockpit has to be blue or green only. Class B goggles (Typically referred to as NVIS) have a 665 nm cut-off, which allow use of a greeny-yellow and a dirty-red without disrupting the goggles.
Cockpit light has to be specially filtered. Normal colored filters still let through enough energy in the longer wavelengths to affect the goggle performance. The special filters are designed with sharp cut-off characteristics to prevent energy from escaping in the long wavelengths.
Class A goggles are recommended for operation "below tree-top" level. They give you the extra edge required for NOE (Nap of the earth) flying. Class A goggles do a better job of picking out power lines and other obstacles. SOA and SOF helicopters, for example, are typically set up for Class A goggles. Those cockpits are usually blue-green only with some limited use of other colors (even though the result is not totally class-A compliant.)
Class B goggles are the more typical NVGs in use in civil (police) and other military aviation application. They allow the use of other colors in the cockpit, although special filtering is still required. Pretty much any adaptation of civil electronic displays for NVG has to be for Class B rather than Class A use.
Hope that helps.
NVG (Night vision goggles) is commonly used to describe light amplification goggles or image intensifiers. The goggles typically mount on a bracket from a helmet, like a set of binoculars. The goggles operate by taking in an ambient light image and amplifying it agaist a green phosphor screen inside the binocular. The result is that with very minimal light (eg, even starlight coming through cloud layer on a moonless night) you have enough light to see. This differs from FLIR which uses the heat from objects. NVG has a bit of that - since it covers part of that spectrum, but it is really using extremely low levels of natural light reflected off objects, rather than heat emitted from an object.
The original goggles used in aviation (late 70s early 80s) were Gen-II goggles and amplied the entire visible spectrum and then some. This required that cockpit and instrument lighting be dimmed so much that it was not visible to the naked eye. It also required the pilot to continually shift focus in and out of the cockpit - which the Army found to be a good way to kill pilots.
Gen III goggles only amplify light in the red and infra-red end of the spectrum. Actually the spectrum is optimized for starlight reflected off vegitation. By only amplifying this portion of the spectrum, the cockpit can use the other part for its lighting without disturbing the goggles. Gen-III goggles mount slightly off the helmet and are focused for outside viewing. The pilot looks below and past the goggles to view cockpit instruments without looking through the goggles.
We typically talk about Class A and Class B goggles. The difference is defined in MIL-L-85762A which is the controlling spec for this technology, and for the cockpit lighting. Class A goggles have a 625 nm wavelength cut-off which means everything in the cockpit has to be blue or green only. Class B goggles (Typically referred to as NVIS) have a 665 nm cut-off, which allow use of a greeny-yellow and a dirty-red without disrupting the goggles.
Cockpit light has to be specially filtered. Normal colored filters still let through enough energy in the longer wavelengths to affect the goggle performance. The special filters are designed with sharp cut-off characteristics to prevent energy from escaping in the long wavelengths.
Class A goggles are recommended for operation "below tree-top" level. They give you the extra edge required for NOE (Nap of the earth) flying. Class A goggles do a better job of picking out power lines and other obstacles. SOA and SOF helicopters, for example, are typically set up for Class A goggles. Those cockpits are usually blue-green only with some limited use of other colors (even though the result is not totally class-A compliant.)
Class B goggles are the more typical NVGs in use in civil (police) and other military aviation application. They allow the use of other colors in the cockpit, although special filtering is still required. Pretty much any adaptation of civil electronic displays for NVG has to be for Class B rather than Class A use.
Hope that helps.
Civil NVG
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The only civilian UK operation I know of is Devon and Cornwall police. They use a BK117 and (I believe) 2 pilots. North Wales police uses NVG, but only for the police osbervers (at the moment).
Max, I believe Canada is the closest to getting civilian operators clearance to operate on NVG, my question is how will it be regulated. NVG skills are not difficult to aquire with the right training but will civilian operators pay the costs of the continuation training that is required - the skills are perishable just like instrument flying and must be practised.
I read an article in one of the helicopter comics recently that suggested that IFR training wasn't required as part of, or a precursor to, an NVG qualification. Methinks the writer has never encountered bad weather on goggles - as most NVG pilots will tell you by the time you realise that weather has degraded the goggle picture, you are already in the middle of it and are very likely to need your IFR skills to get out.
If HEMS and police start to operate on NVG, how long will it be before private pilots claim their right to use them too - then we will see some interesting accidents.
I read an article in one of the helicopter comics recently that suggested that IFR training wasn't required as part of, or a precursor to, an NVG qualification. Methinks the writer has never encountered bad weather on goggles - as most NVG pilots will tell you by the time you realise that weather has degraded the goggle picture, you are already in the middle of it and are very likely to need your IFR skills to get out.
If HEMS and police start to operate on NVG, how long will it be before private pilots claim their right to use them too - then we will see some interesting accidents.
There is a move to increase the regulation with civilian NVG in the US i believe because jo bloggs could purchase a pair of NVG's from the downtown gunstore and go flying in his helo at night on goggles
Here in the Uk in light of the growing interest in NVG, particularly with us in the police world, but obviously GA in general, the CAA are showing a keen interest in the matter and will be regulating accordingly. They are listening to commercial inputs, and it is hoped the end product will benefit all.
The Home Office is actively promoting the procurement of said items for public service helos.
Interestingly one of the main advantages for using NVG is the ability to avoid bad weather.
Here in the Uk in light of the growing interest in NVG, particularly with us in the police world, but obviously GA in general, the CAA are showing a keen interest in the matter and will be regulating accordingly. They are listening to commercial inputs, and it is hoped the end product will benefit all.
The Home Office is actively promoting the procurement of said items for public service helos.
Interestingly one of the main advantages for using NVG is the ability to avoid bad weather.