Night Vision Goggles (NVG discussions merged)
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.
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.
Helmetfire - we fly with Omni4 goggles and the visual acuity is usually 20/40 -we check them on a Hoffman box so the assessment is accurate - with a really good set you might get 20/35 - I don't know who might fly with better than Omni4 (probably SF) but it's not us - however the prospect of 20/20 is interesting - that would probably allow us to winch on NVG as precisely as we can on white light.
As I'm sure you know, the limited FOV is mainly an problem at low level and on approach because it requires constant head movements to scan for obstacles and assess rates of closure - not as much of an issue at 500' and above where you are primarily using goggles as an aid to lookout
We will have to wait for a new aircraft (SARH) to get moving map displays but that is only a couple of years away
What is your required rapid response time from phone call to airborne?
As I'm sure you know, the limited FOV is mainly an problem at low level and on approach because it requires constant head movements to scan for obstacles and assess rates of closure - not as much of an issue at 500' and above where you are primarily using goggles as an aid to lookout
We will have to wait for a new aircraft (SARH) to get moving map displays but that is only a couple of years away
What is your required rapid response time from phone call to airborne?
Omnibus VII "Pinacles" are reputedly 20/20 or near enough. They are available to civilian operators in the USA, but not outside. The best you can get outside the US is the IVs, and that is what we use in Oz. The NVG are "detuned" according to limitations set by the US State Department in terms of signal to noise (which affects accuity) and minimum halo sizes. Regardless, the exported IV is an outstanding goggle that produces a civilian safe standard of image for the first time in NVG evolution.
Either way, 20/40 is far superior to 20/200.
It is hard to explain in this brief format, but the use of white light has so fundamentally changed the way we fly on NVG that some of the old military mantras are less applicable than the absolutes they used to be. The head scan on late finals and in the hover is one of those. Designed to overcome the reduced FOV, the head scan acted like a weather radar sweep, it enabled the mind to build an accurate picture of obstacles, closure rates and drift in the hover. With white light however you can simply use a "look around" view moving your eyes and not your head. The white light also provides you a great deal of peripheral vision which is critical in the maintenance of an accurate hover - and the lack of it in the military (white light would get you shot) is why NVG hovering was so hard.
I should also say that the white light has not alleviated the rear seat crewman head movement requirements, and as our crewman instructor is want to say: if you come back from a winching sortie without a sore neck then you have not been scanning properly.
That has translated into NVG winching being just as you imagined: we can winch as precisely on NVG as we can on white light. We have changed the emphasis on the reference points for the hover, but the winching is even easier than white light only because you have a horizon through the NVG and when the winch is completed you are not departing a black hole. We often practice NVG failure in the winch for the pilot and crewie (not together) and have yet to see any adverse reaction. There is no way we would have practiced this in the military as goggle failure would mean a total loss of references, but that is not the case with white light civvy winching in which your primary references are actually the unaided ones!
Response times are a whole bag of worms. The phrase "required response times" evokes echos of a bygone era in which we simply failed to understand the enormous safety implications of such a "requirement". Organisations resorting to "required" response times do so because it is the quickest and easiest "thing" to measure and compare dicks over. The safety outcomes and patient outcomes are almost never measured. And the complexity of such measurements fails to justify "contracted" or "required" response times in any way. IMHO.
Rant over. On both our multirole and rapid response mission profiles the actual take off time is dictated by completion of the required planning tasks, not by any time limit. Our principal is that the time taken to respond does not dictate the the safety of the response - the planning tasks do. For example, if you pause for a chat on the way out to the helo and have a slower response than the other helo, are you necessarily safer?
The complexity of the multirole mission (SAR in particular) can result in response delays of over an hour, though typically not more than 15 minutes. The rapid response model on the other hand enables take off in 2 minutes (day or NVG) from the decision to go, but that is because it is a single role system: limited range, limited patient group, crew, configuration and equipment are not altered.
I note your part in the previous debates on response times so let me finish by saying that like crew mixes, response times are not comparable across roles, certainly not across differing environmental and teraain conditions, and rarely even across operating cultures. One is not wrong or unsafe, it is just different.
Either way, 20/40 is far superior to 20/200.
It is hard to explain in this brief format, but the use of white light has so fundamentally changed the way we fly on NVG that some of the old military mantras are less applicable than the absolutes they used to be. The head scan on late finals and in the hover is one of those. Designed to overcome the reduced FOV, the head scan acted like a weather radar sweep, it enabled the mind to build an accurate picture of obstacles, closure rates and drift in the hover. With white light however you can simply use a "look around" view moving your eyes and not your head. The white light also provides you a great deal of peripheral vision which is critical in the maintenance of an accurate hover - and the lack of it in the military (white light would get you shot) is why NVG hovering was so hard.
I should also say that the white light has not alleviated the rear seat crewman head movement requirements, and as our crewman instructor is want to say: if you come back from a winching sortie without a sore neck then you have not been scanning properly.
That has translated into NVG winching being just as you imagined: we can winch as precisely on NVG as we can on white light. We have changed the emphasis on the reference points for the hover, but the winching is even easier than white light only because you have a horizon through the NVG and when the winch is completed you are not departing a black hole. We often practice NVG failure in the winch for the pilot and crewie (not together) and have yet to see any adverse reaction. There is no way we would have practiced this in the military as goggle failure would mean a total loss of references, but that is not the case with white light civvy winching in which your primary references are actually the unaided ones!
Response times are a whole bag of worms. The phrase "required response times" evokes echos of a bygone era in which we simply failed to understand the enormous safety implications of such a "requirement". Organisations resorting to "required" response times do so because it is the quickest and easiest "thing" to measure and compare dicks over. The safety outcomes and patient outcomes are almost never measured. And the complexity of such measurements fails to justify "contracted" or "required" response times in any way. IMHO.
Rant over. On both our multirole and rapid response mission profiles the actual take off time is dictated by completion of the required planning tasks, not by any time limit. Our principal is that the time taken to respond does not dictate the the safety of the response - the planning tasks do. For example, if you pause for a chat on the way out to the helo and have a slower response than the other helo, are you necessarily safer?
The complexity of the multirole mission (SAR in particular) can result in response delays of over an hour, though typically not more than 15 minutes. The rapid response model on the other hand enables take off in 2 minutes (day or NVG) from the decision to go, but that is because it is a single role system: limited range, limited patient group, crew, configuration and equipment are not altered.
I note your part in the previous debates on response times so let me finish by saying that like crew mixes, response times are not comparable across roles, certainly not across differing environmental and teraain conditions, and rarely even across operating cultures. One is not wrong or unsafe, it is just different.
Helmetfire - we have been mixing NVG and white light for many years in SAR, since we don't have the military imperative of covert ops we adopt what is best practise and it does work extremely well in many situations.
However, although the use of white light on the approach gives you more information, if you are looking through NVG you still need to scan for that information unless by 'moving your eyes' you mean looking under the goggles at the outside world.
This can have its benefits but usually only as a help to decide when to transfer from NVG to white light - trying to use both at the same time begs the question of what you are trying to achieve. If the picture on white light is not good enough then stay on goggles using white light to improve the illumination - if the picture on white light is good enough then transfer completely to white light. The head scan is still required to check for wires and obstacles.
Trying to assimilate the information from both under and through the goggles isn't impossible but at critical stages like landing or manoeuvering in the low hover, I would suggest that using either one or the other is best, especially for less experienced pilots.
As to winching on NVG, I have done some ad-hoc trials to the same situations (cliffs, over water, decks) both on white light and NVG and come to the conclusion that where absolute precision is required and references are available (cliffs and decks) white light gives (due to the better visual acuity) the best hover but where references are limited anyway (over water) usually NVG with the assistance of white light is the best option.
We have the luxury of 2 pilots so one can always stay on goggles for the flyaway if required - personally, after a few years of doing this job I have my goggles set so I can see my white light references on the cliff but can still 'look up' into the NVG for horizon and obstacle awareness so that I could react quicker to an engine failure instead of handing over control.
I wasn't having a pop over response times, merely asking a question - although we have specified response times the Captain would always be justified in exceeding those if more planning was required.
However, although the use of white light on the approach gives you more information, if you are looking through NVG you still need to scan for that information unless by 'moving your eyes' you mean looking under the goggles at the outside world.
This can have its benefits but usually only as a help to decide when to transfer from NVG to white light - trying to use both at the same time begs the question of what you are trying to achieve. If the picture on white light is not good enough then stay on goggles using white light to improve the illumination - if the picture on white light is good enough then transfer completely to white light. The head scan is still required to check for wires and obstacles.
Trying to assimilate the information from both under and through the goggles isn't impossible but at critical stages like landing or manoeuvering in the low hover, I would suggest that using either one or the other is best, especially for less experienced pilots.
As to winching on NVG, I have done some ad-hoc trials to the same situations (cliffs, over water, decks) both on white light and NVG and come to the conclusion that where absolute precision is required and references are available (cliffs and decks) white light gives (due to the better visual acuity) the best hover but where references are limited anyway (over water) usually NVG with the assistance of white light is the best option.
We have the luxury of 2 pilots so one can always stay on goggles for the flyaway if required - personally, after a few years of doing this job I have my goggles set so I can see my white light references on the cliff but can still 'look up' into the NVG for horizon and obstacle awareness so that I could react quicker to an engine failure instead of handing over control.
I wasn't having a pop over response times, merely asking a question - although we have specified response times the Captain would always be justified in exceeding those if more planning was required.
I would put a big question mark regarding a 20/20 VA with a NVD. Maybe using some "creative" measurement method?
The export limitations for any NVD from US for quite some time are based on the FOM parameter (Figure of Merit). FOM=SNR*Resolution of the tube.
The limit for UK/OZ/ etc... is, if I remember, FOM=1600, which would be the equivalent to the old specs of the OMNI IV tubes. The tubes with gated power supplies are not exported outisde US. If you want some, you have to look for a non-US manufacturer.
I don't think anyone is "detuning" the tubes. It's just a question of choosing the ones having parameters below a given limit.
Arrakis
The export limitations for any NVD from US for quite some time are based on the FOM parameter (Figure of Merit). FOM=SNR*Resolution of the tube.
The limit for UK/OZ/ etc... is, if I remember, FOM=1600, which would be the equivalent to the old specs of the OMNI IV tubes. The tubes with gated power supplies are not exported outisde US. If you want some, you have to look for a non-US manufacturer.
I don't think anyone is "detuning" the tubes. It's just a question of choosing the ones having parameters below a given limit.
Arrakis
Thanks crab, you have confirmed some of the outcomes that we have experienced. I am intrested, if you have time, in you detailing your over water NVG winching experiences, and acft equipment in terms of autopilot/auto hover etc.
We do not do such operations so we would be keen to hear it.
I note that you guys have come to the same conclusion in terms of sometimes it is better to be goggled up, and some times it is not. Indeed the Swiss when we visited, stated that they goggle up and degoggle as required by the situation. For cliff winches for example, they would approach to the hover on NVG, then degoggle in the hover for the winch, depart and goggle up in the fly away.
Unfortunately, that option is not available in Oz as the NVG Order prescriptively requires us to be on the ground or above LSALT to change status of the crew (between aided and unaided). Oz was the only country we came across with this requirement. Others advised a control (NZ system for example) but most did not regulate this aspect at all. How do you guys control it, and with your experience, what do you think of the Swiss approach?
How do any others do this?
Aarakis: I agree. My use of the phrase "detuned" was incorrect.
We do not do such operations so we would be keen to hear it.
I note that you guys have come to the same conclusion in terms of sometimes it is better to be goggled up, and some times it is not. Indeed the Swiss when we visited, stated that they goggle up and degoggle as required by the situation. For cliff winches for example, they would approach to the hover on NVG, then degoggle in the hover for the winch, depart and goggle up in the fly away.
Unfortunately, that option is not available in Oz as the NVG Order prescriptively requires us to be on the ground or above LSALT to change status of the crew (between aided and unaided). Oz was the only country we came across with this requirement. Others advised a control (NZ system for example) but most did not regulate this aspect at all. How do you guys control it, and with your experience, what do you think of the Swiss approach?
How do any others do this?
Aarakis: I agree. My use of the phrase "detuned" was incorrect.
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We operate on NVGs for HEMS/Pol....ITT F4949 goggles with F9800P tubes at 64 line pairs resolution.
We do not advocate goggling or de-goggling other than at a safe height, certainly not at low levels or at hover....definitely from experience not a habit we are comfortable with.
Secondly we have a rule of thumb to deal with reduced vis or very poor contrast conditions....if you are down to 400' and 60kts then abort and turn back seek alternative method (such as IFR).
We use landing light for obstacle detection and augmentation, especially in poor ambient light conditions. IR landing light for covert ops.
If pilot /acft IFR than wx minima can be 3000m and clear of cloud. If night VFR only then wx must be NVMC.
We have found that there is little point over-controlling NVGs, good initial training with follow-up period of supervision and simple set of rules is more than adequate to conduct a safe NVG op.
We do not advocate goggling or de-goggling other than at a safe height, certainly not at low levels or at hover....definitely from experience not a habit we are comfortable with.
Secondly we have a rule of thumb to deal with reduced vis or very poor contrast conditions....if you are down to 400' and 60kts then abort and turn back seek alternative method (such as IFR).
We use landing light for obstacle detection and augmentation, especially in poor ambient light conditions. IR landing light for covert ops.
If pilot /acft IFR than wx minima can be 3000m and clear of cloud. If night VFR only then wx must be NVMC.
We have found that there is little point over-controlling NVGs, good initial training with follow-up period of supervision and simple set of rules is more than adequate to conduct a safe NVG op.
Helmet Fire - sorry for the delay in replying but I have been away camping in a rather damp Cornish field
Our SOP for night wet winching (person in the water or small vessel, raft etc) would be to establish the hover with the casualty in the 2:30 position and hand control to the radop/winchop using the Hover Trim system since he is the one who can see what is happening under the aircraft.
The Sea King has an auto hover (4 axis with rad-alt hold) and the height can be wound up and down as required (Mk3 to 70', Mk3A to 199') if the downwash is affecting the survivor/vessel. The hover trim controller is by the cabin door and gives 10% pitch and roll control authority to the radop/winchop to manoeuvre the aircraft and operate the winch.
The rearcrew would be on white light throughout and the white light hover flood lights would be on to illuminate the casualty - the pilots might be on NVG or white light depending on conditions.
With more than 10 -15 kts of wind, the downwash is behind the cockpit so a combination of NVG and white light is usually appropriate (the steerable landing lamps allow you to see more of the surface information) and when we are practicing manual recoveries (pilot flying with the cyclic autopilot modes released) this is usually the configuration that allows you to provide the best service but not everyone (often depending on experience levels) is always comfortable with this, preferring to use the radop/winchops patter and the Low Velocity Indicator (LVI or hovermeter) to assess rates of movement. The LVI is, bizzarely, better in the analogue Mk 3 than it is in the digital Mk3A!
With lower wind strengths, the downwash tends to envelop the aircraft in a recirculating ball of spray rendering the NVG useless and white light not much better (all the light is reflected back from the fast moving spray, like when you put your landing lamp on in the cruise and realise it is raining but much worse) so it is back to the LVI and patter again.
The instrument hover is a relatively slow process since great care must be taken not to develop rapid rates of movement, especially backwards, and it is quite possible to become disorientated on a gloopy night - hence our SOP to utilise the hover trim as the radop/winchop has generally good visual references throughout.
We pretty much operate to the Swiss concept of ops, again the luxury of 2 pilots means one can always stay on NVG and there can be a safe handover of control whilst the other degoggles/goggles up. I do encourage pilots to get to a stable, close hover on NVG before transferring to white light but that is often just lack of confidence by junior pilots in their NVG hovering, especially close to cliffs, and is soon sorted with some practice.
We also do a lot of high hovering on NVG (1000 to 1500') for FLIR searches which again makes for an interesting scan and the value of the LVI cannot be overstated - it is very easy to end up going backwards at 20 -30 knots when your hover references are such a long way away if you don't scan the LVI regularly, especially during a protracted search when fatigue and boredom set in.
Our SOP for night wet winching (person in the water or small vessel, raft etc) would be to establish the hover with the casualty in the 2:30 position and hand control to the radop/winchop using the Hover Trim system since he is the one who can see what is happening under the aircraft.
The Sea King has an auto hover (4 axis with rad-alt hold) and the height can be wound up and down as required (Mk3 to 70', Mk3A to 199') if the downwash is affecting the survivor/vessel. The hover trim controller is by the cabin door and gives 10% pitch and roll control authority to the radop/winchop to manoeuvre the aircraft and operate the winch.
The rearcrew would be on white light throughout and the white light hover flood lights would be on to illuminate the casualty - the pilots might be on NVG or white light depending on conditions.
With more than 10 -15 kts of wind, the downwash is behind the cockpit so a combination of NVG and white light is usually appropriate (the steerable landing lamps allow you to see more of the surface information) and when we are practicing manual recoveries (pilot flying with the cyclic autopilot modes released) this is usually the configuration that allows you to provide the best service but not everyone (often depending on experience levels) is always comfortable with this, preferring to use the radop/winchops patter and the Low Velocity Indicator (LVI or hovermeter) to assess rates of movement. The LVI is, bizzarely, better in the analogue Mk 3 than it is in the digital Mk3A!
With lower wind strengths, the downwash tends to envelop the aircraft in a recirculating ball of spray rendering the NVG useless and white light not much better (all the light is reflected back from the fast moving spray, like when you put your landing lamp on in the cruise and realise it is raining but much worse) so it is back to the LVI and patter again.
The instrument hover is a relatively slow process since great care must be taken not to develop rapid rates of movement, especially backwards, and it is quite possible to become disorientated on a gloopy night - hence our SOP to utilise the hover trim as the radop/winchop has generally good visual references throughout.
We pretty much operate to the Swiss concept of ops, again the luxury of 2 pilots means one can always stay on NVG and there can be a safe handover of control whilst the other degoggles/goggles up. I do encourage pilots to get to a stable, close hover on NVG before transferring to white light but that is often just lack of confidence by junior pilots in their NVG hovering, especially close to cliffs, and is soon sorted with some practice.
We also do a lot of high hovering on NVG (1000 to 1500') for FLIR searches which again makes for an interesting scan and the value of the LVI cannot be overstated - it is very easy to end up going backwards at 20 -30 knots when your hover references are such a long way away if you don't scan the LVI regularly, especially during a protracted search when fatigue and boredom set in.
Thanks for the info guys.
Rivnut: you mention that you have had experiences that make you guys limit goggle up/degoggle hieghts. What are the expereinces and what are the limitations? It was interesting to me that during the 20 plus years of Swiss ops they have not had the same issues.
crab: thanks for the insights. You made a point that I was very interested in examining and have been doing so over here:
Do you mean setting your eye relief? I am very interested in discussing the eye relief from a civ white light perspective Vs a military non white light use. It seems you have also discovered what we are finding - an increased eye relief may suit civ ops where it did not suit mil ops.
Rivnut: you mention that you have had experiences that make you guys limit goggle up/degoggle hieghts. What are the expereinces and what are the limitations? It was interesting to me that during the 20 plus years of Swiss ops they have not had the same issues.
crab: thanks for the insights. You made a point that I was very interested in examining and have been doing so over here:
personally, after a few years of doing this job I have my goggles set so I can see my white light references on the cliff but can still 'look up' into the NVG for horizon and obstacle awareness so that I could react quicker to an engine failure instead of handing over control.
Helmet Fire - a lot of pilots tend to have the goggles too close to their eyes in the mistaken belief that it will give them a better field of view - when you are looking down a pair of toilet roll tubes you can see very little more by jamming them against your eyeballs than you can with them a comfortable distance (say 2 cm) away.
Personally I have them as far forward as they will go on the adjusters simply because I get a much better view inside the cockpit without having to crane my neck into odd angles. Any small loss (and I mean small) in FoV is made up for by scanning which I would have to do anyway. The advantage is definitely clear when you come onto mixed-light ops where glancing under the goggles is easier and the decision to de-goggle (if neccessary) can be made whilst comparing the two pictures. The added bonus is that you are not limited to your pool of white light when cliff/mountain winching and you retain the awareness of obstacles and terrain, especially important if you have to deal with an emergency whilst winching.
As I mentioned in the previous post, operating on white light whilst still wearing the goggles is only really feasible if you have the eye-relief set well forward and it is something worth trying on a training flight before doing it operationally.
Not everyone finds it comfortable to start with and it is not always a perfect solution - I was winching at the bottom of a narrow valley a few weeks ago with hover references on white light but an escape route (down the valley) that had to be flown on NVG (and quickly if a flyaway from an engine fail was to be feasible) and I was working hard against disorientation since I also needed to use my NVG references to help stop me drifting since the terrain was sloping and the white light references were moving (trees and grass blowing in the wind/downwash). I had an instrument style abort option if required but it was one of those situations where neither pure white light nor NVG hover would give me the hover accuracy and the flyaway option.
Personally I have them as far forward as they will go on the adjusters simply because I get a much better view inside the cockpit without having to crane my neck into odd angles. Any small loss (and I mean small) in FoV is made up for by scanning which I would have to do anyway. The advantage is definitely clear when you come onto mixed-light ops where glancing under the goggles is easier and the decision to de-goggle (if neccessary) can be made whilst comparing the two pictures. The added bonus is that you are not limited to your pool of white light when cliff/mountain winching and you retain the awareness of obstacles and terrain, especially important if you have to deal with an emergency whilst winching.
As I mentioned in the previous post, operating on white light whilst still wearing the goggles is only really feasible if you have the eye-relief set well forward and it is something worth trying on a training flight before doing it operationally.
Not everyone finds it comfortable to start with and it is not always a perfect solution - I was winching at the bottom of a narrow valley a few weeks ago with hover references on white light but an escape route (down the valley) that had to be flown on NVG (and quickly if a flyaway from an engine fail was to be feasible) and I was working hard against disorientation since I also needed to use my NVG references to help stop me drifting since the terrain was sloping and the white light references were moving (trees and grass blowing in the wind/downwash). I had an instrument style abort option if required but it was one of those situations where neither pure white light nor NVG hover would give me the hover accuracy and the flyaway option.
Exactly our conclusions.
Close eye relief (18mm or so) gives a larger retinal image size of the NVG picture than does an extended eye relief of greater than say 30mm, but it gives no appreciable increase in FOV of the image.
For Mil Ops with only the NVG image to rely on, the image size was of great importance as it was the only source of external references. For Civ Ops, you are more likely to be hovering off unaided references, thus the retinal image size (of the NVG image) is not as critical - the unaided references are. Accordingly, what becomes of more importance is getting the NVG eye relief sufficient that you can hover off the white light references without being too distracted. Unfortunately, all the books that come with the NVG say that eye relief should be 18 to 25mm.
After a lot of recent NVG white light hovering I have found that the brain is capable of giving a clear unaided image even with the goggles still in the operational position - but I am talking about 40 odd hours of hovering in a month! I am curious as to the cause of this, and am wondering how it connects to the vision phenomena Apache pilots have to master to run different eyes on different tasks.
Close eye relief (18mm or so) gives a larger retinal image size of the NVG picture than does an extended eye relief of greater than say 30mm, but it gives no appreciable increase in FOV of the image.
For Mil Ops with only the NVG image to rely on, the image size was of great importance as it was the only source of external references. For Civ Ops, you are more likely to be hovering off unaided references, thus the retinal image size (of the NVG image) is not as critical - the unaided references are. Accordingly, what becomes of more importance is getting the NVG eye relief sufficient that you can hover off the white light references without being too distracted. Unfortunately, all the books that come with the NVG say that eye relief should be 18 to 25mm.
After a lot of recent NVG white light hovering I have found that the brain is capable of giving a clear unaided image even with the goggles still in the operational position - but I am talking about 40 odd hours of hovering in a month! I am curious as to the cause of this, and am wondering how it connects to the vision phenomena Apache pilots have to master to run different eyes on different tasks.
I think the brain training required is very similar but probably not quite as demanding as the Apache 'bag' training and I know that adapting to it is a very individual issue. I will check the actual eye relief on our NVG when I get back to work.
It is not unlike using a camcorder with both eyes open but one looking down the viewfinder - I had to use this technique whilst skiing and videoing my kids so that I didn't crash or fall over!
It's like so many things in the aviation world, it can be done but to do it safely requires training and practise.
It might be that I favour larger eye-relief because my eyes are getting older and I'm more used to dealing with a smaller retinal image as I have to hold books further away to focus!!
It is not unlike using a camcorder with both eyes open but one looking down the viewfinder - I had to use this technique whilst skiing and videoing my kids so that I didn't crash or fall over!
It's like so many things in the aviation world, it can be done but to do it safely requires training and practise.
It might be that I favour larger eye-relief because my eyes are getting older and I'm more used to dealing with a smaller retinal image as I have to hold books further away to focus!!
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Who is doing what in Australia?
Which Operators in Oz have gone down the NVG pathway (legally using them that is) and what type of Goggles are they using?
I understand that CASA have a very short list of approved units: ITT and the soon to be modified NL93's, think they are going to be designated the NL94au's.
Proven resolution specifications reflect: 20 / 25 via Green Auto Gating Tubes.
How does these European Goggles compare with the ITT system?
I understand that CASA have a very short list of approved units: ITT and the soon to be modified NL93's, think they are going to be designated the NL94au's.
Proven resolution specifications reflect: 20 / 25 via Green Auto Gating Tubes.
How does these European Goggles compare with the ITT system?
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Great thread!!
This is one of the best threads I have seen in a long time. Too often both here and elsewhere on the web these discussions dissolve into acrimony because people are not willing to accept that there is more than one way to do a job or use a particular piece of kit.
Coming from a military background it is very interesting to see how you guys are using white light to help you achieve your objectives and also the differing arrangements in place to transfer between aided and unaided flight.
Keep the posts coming!
Coming from a military background it is very interesting to see how you guys are using white light to help you achieve your objectives and also the differing arrangements in place to transfer between aided and unaided flight.
Keep the posts coming!
I agree, there is no way the brain training thing is as demanding as the Apache system. They have to do it from day 1 just to control the aircraft effectively, but what I am talking about is a consequential thing that is not critical for aircraft control.
I like the analogy with the camcorder, and I have been trying to find some more. The most common one uncovered in our discussions was sunglasses. The first time you put sunnies on with small frames and closed peripheral blocks, you can find it a little claustrophobic and daunting, but after a while you do not notice at all, and your head movement begins to automatically compensate for the peripheral degradation. Similarly when you go from a big lens set of glasses to small ones you will notice heaps of frame in your vision, but that dissipates as time goes on and you dont notice it at all.
I have also noticed that on NVG. The Americans tend to teach people to tie the neck cords off to their helmet, whereas we leave them dangling down around the necks. The cord is then in the peripheral view, but it is only two or three flights before the pilot does not even notice the cords at all.
In Oz, as I understand it, all current approved operators use ITT F4949 (one previously used another brand but has changed).
Operators I know of include (there are others):
Hunter Rescue, VicPol, EMQ, WAPol, RotorLift (an approved Training Provider), Australian Helicopters, and CareFlight (also an approved Training Provider).
On the cusp of completing training and approvals are:
PolAir NSW, and CHC Sydney.
I like the analogy with the camcorder, and I have been trying to find some more. The most common one uncovered in our discussions was sunglasses. The first time you put sunnies on with small frames and closed peripheral blocks, you can find it a little claustrophobic and daunting, but after a while you do not notice at all, and your head movement begins to automatically compensate for the peripheral degradation. Similarly when you go from a big lens set of glasses to small ones you will notice heaps of frame in your vision, but that dissipates as time goes on and you dont notice it at all.
I have also noticed that on NVG. The Americans tend to teach people to tie the neck cords off to their helmet, whereas we leave them dangling down around the necks. The cord is then in the peripheral view, but it is only two or three flights before the pilot does not even notice the cords at all.
In Oz, as I understand it, all current approved operators use ITT F4949 (one previously used another brand but has changed).
Operators I know of include (there are others):
Hunter Rescue, VicPol, EMQ, WAPol, RotorLift (an approved Training Provider), Australian Helicopters, and CareFlight (also an approved Training Provider).
On the cusp of completing training and approvals are:
PolAir NSW, and CHC Sydney.
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Crab and Helmet: Great discussion, thanks. Perhaps I missed it in one of your posts but when using white light in concert with NVG's, is the white light source you are using a fixed position landing light or a movable search light?
I have a lot of experience with open ocean NVG and unaided hoisting and concur with Crab's learned technique of setting the NVG's high up for the horizon and being able to scan underneath them for both the instruments and peripheral vision. However, I personally don't like the tubes to be far away, perhaps just a difference in helmet configuration or maybe just how I learned, not important I guess, to each his own right?
In my current airframe, each pilot has a movable search light on the nose. The use of a pilot controlled search light (typically the search light on opposite side of the hoist manipulated by the safety pilot) varies depending on the scene, just as someone previously mentioned. But in our case, the hoist operator becomes unaided once we begin the process of actually getting ready to hoist, and only after we have successfully arrived to the scene (which is routinely a combo of instrument procedures and visual cues). Once we have established the need to actually hoist someone, the safety pilot will move the searchlight to a position where it helps the hoist operator and to where it has minimal impact on the NVG pilot at controls. In those no wind conditions, the milkbowl effect is definitely a factor to contend with, and the white light doesn't help, but if the power is available, we can mitigate that with altitude. If in the milkbowl, I personally find myself scanning more around the goggles, jumping between instruments and what I can see in the water, however as safety pilot I am more instruments and horizon (if we even one) on NVGs.
I think that when you have NVG's and you commence with an open ocean SAR op, if you treat getting to the scene as a process more oriented towards the use of instruments (regardless if you have a full moon & CAVU) and use standardized procedures to allow you to systematically get established in a good position to assess your next move, then you will most likely minimize your fear factor when you actually commence the hoist, whether you are on NVG, unaided, or using a combo depending on your crew configuration. I have seen to many guys rely to heavily on NVG's to arrive near a sinking boat or person in the water, only then to rely very heavily on the safety pilot to keep them from flying into the water.
Cheers!
I have a lot of experience with open ocean NVG and unaided hoisting and concur with Crab's learned technique of setting the NVG's high up for the horizon and being able to scan underneath them for both the instruments and peripheral vision. However, I personally don't like the tubes to be far away, perhaps just a difference in helmet configuration or maybe just how I learned, not important I guess, to each his own right?
In my current airframe, each pilot has a movable search light on the nose. The use of a pilot controlled search light (typically the search light on opposite side of the hoist manipulated by the safety pilot) varies depending on the scene, just as someone previously mentioned. But in our case, the hoist operator becomes unaided once we begin the process of actually getting ready to hoist, and only after we have successfully arrived to the scene (which is routinely a combo of instrument procedures and visual cues). Once we have established the need to actually hoist someone, the safety pilot will move the searchlight to a position where it helps the hoist operator and to where it has minimal impact on the NVG pilot at controls. In those no wind conditions, the milkbowl effect is definitely a factor to contend with, and the white light doesn't help, but if the power is available, we can mitigate that with altitude. If in the milkbowl, I personally find myself scanning more around the goggles, jumping between instruments and what I can see in the water, however as safety pilot I am more instruments and horizon (if we even one) on NVGs.
I think that when you have NVG's and you commence with an open ocean SAR op, if you treat getting to the scene as a process more oriented towards the use of instruments (regardless if you have a full moon & CAVU) and use standardized procedures to allow you to systematically get established in a good position to assess your next move, then you will most likely minimize your fear factor when you actually commence the hoist, whether you are on NVG, unaided, or using a combo depending on your crew configuration. I have seen to many guys rely to heavily on NVG's to arrive near a sinking boat or person in the water, only then to rely very heavily on the safety pilot to keep them from flying into the water.
Cheers!
Thanks for joining the discussion Phrogman. I just dont have the cahoonies to water hoist at night anymore, and I have never done it with NVG. I do not fly an auto hover equipped frame either!
As for the onshore winching, we leave the crewman goggled up. We have also fitted white external lights to the exterior of the airframe near the tailboom, as well as a downlight (white). These lights really provide great illumination for the surrounding trees and obstacles and make the crewman's job just so much easier. These white lights are specifically set up as to not impeded the crewman's scan.
In Oz, you must have a pilot steerable searchlight (in both pitch and roll) from the flight controls in order to operate to unprepared HLS (night outlandings).
We have removed the SX16 from our 109 due too much illum for NVG and rely on a single 450W white seachlight and landing light. The BKs we operate in the SAR role have a SX5 fitted but are almost never used due to excessive illum and disruption of the NVG image below 100ft. We again rely on the 450W white searchlights instead, and we keep the SX5 on for a backup or for high level search requirements.
I measured my eye relief last night and even I was surprised: 39mm!!
As for the onshore winching, we leave the crewman goggled up. We have also fitted white external lights to the exterior of the airframe near the tailboom, as well as a downlight (white). These lights really provide great illumination for the surrounding trees and obstacles and make the crewman's job just so much easier. These white lights are specifically set up as to not impeded the crewman's scan.
In Oz, you must have a pilot steerable searchlight (in both pitch and roll) from the flight controls in order to operate to unprepared HLS (night outlandings).
We have removed the SX16 from our 109 due too much illum for NVG and rely on a single 450W white seachlight and landing light. The BKs we operate in the SAR role have a SX5 fitted but are almost never used due to excessive illum and disruption of the NVG image below 100ft. We again rely on the 450W white searchlights instead, and we keep the SX5 on for a backup or for high level search requirements.
I measured my eye relief last night and even I was surprised: 39mm!!
Phrogman - our SOPs are as you suggest, overwater letdowns are conducted the same way ie as if you were IMC even if you are VMC at night on NVG. That way none of the safety calls, rad alt bug setting or NHP monitoring of descents is missed and the NVG are just used to assist in lookout. I have also seen many guys need the assistance of the NHP at the end of an NVG biased approach over the water.
Each pilot has a steerable spot light and there are 4 further flood lights (2 on the underside of the nose and one in each sponson) and the winchop has a steerable spot as well which he can use to assess tip and tail clearances as well as illuminate the winching.
Almost without exception, the winchop will be on white light for winching but if he can see better with NVG (winching through trees is one situation I know it has been done) then he will use them.
Having concentrated greatly on the use of NVG and lights, it is worth highlighting, from my experience, that the most dangerous time, especially over the water, is dusk; there is enough light to fool pilots into thinking they can use day techniques but not enough light to actually do so and it is often the inability to assess accurate rates of closure that catches them out. Mountain flying at dusk is equally fraught with danger, especially if you are trying to make an approach to a feature looking into the setting sun - unaided it is too high contrast and the terrain is in deep shadow and on NVG the picture is just burnt out!
Each pilot has a steerable spot light and there are 4 further flood lights (2 on the underside of the nose and one in each sponson) and the winchop has a steerable spot as well which he can use to assess tip and tail clearances as well as illuminate the winching.
Almost without exception, the winchop will be on white light for winching but if he can see better with NVG (winching through trees is one situation I know it has been done) then he will use them.
Having concentrated greatly on the use of NVG and lights, it is worth highlighting, from my experience, that the most dangerous time, especially over the water, is dusk; there is enough light to fool pilots into thinking they can use day techniques but not enough light to actually do so and it is often the inability to assess accurate rates of closure that catches them out. Mountain flying at dusk is equally fraught with danger, especially if you are trying to make an approach to a feature looking into the setting sun - unaided it is too high contrast and the terrain is in deep shadow and on NVG the picture is just burnt out!
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I suspected you both had movable lights, however due to both of your responses, I now feel quite inadequate with the ones we have
We just use the two pilot controlled lights, and one of those now is at half strength due to the desire for IR (not for the SAR mission). We have the SX-5, but as mentioned, it tends to be a little much down low.
Crab, I am going to have to use your point about dusk and the pitfalls that exist at an upcoming presentation. You flashed me back to a couple of cases and I know exactly what you mean, it is not a common discussion in our community and it needs to be. It is nice to see how others hold the same healthy respect to approaches to the water at night, it is often a variable taken for granted in fledgling operations located near water and who have just acquired NVG's and a hoist. I know of one fairly large public safety operation on the east coast that is tinkering with going goggles soon, and their leadership suggested that they can then expect to go offshore and be able to hoist from a boat, NVG...single pilot. Thoughts?
We just use the two pilot controlled lights, and one of those now is at half strength due to the desire for IR (not for the SAR mission). We have the SX-5, but as mentioned, it tends to be a little much down low. Crab, I am going to have to use your point about dusk and the pitfalls that exist at an upcoming presentation. You flashed me back to a couple of cases and I know exactly what you mean, it is not a common discussion in our community and it needs to be. It is nice to see how others hold the same healthy respect to approaches to the water at night, it is often a variable taken for granted in fledgling operations located near water and who have just acquired NVG's and a hoist. I know of one fairly large public safety operation on the east coast that is tinkering with going goggles soon, and their leadership suggested that they can then expect to go offshore and be able to hoist from a boat, NVG...single pilot. Thoughts?
Just finished having a dusk discussion today! I agree that it is a dangerous time and the quandry between NVG or day is very difficult.
The dusk period and resultant skyglow issues are so variable as to defy any attempt at ANOTHER prescriptive restriction or rule. One outcome based rule of thumb that we are going to trial as an SOP is as follows:
"IF the NVG image is washed out AND you feel you have to go in unaided AND you want to turn on the searchlight to help - then you should postphone the landing until dark enough for NVG"
What we are saying is that if the goggle image is too washed out due too much skyglow illum, then you would want to go in unaided. If you make that determination and then subsequently realise you want/need the searchlight on to help pick up detail: postphone landing until it is dark enough for the NVG image.
Obviously, if faced with this situation, an approach away from skyglow was not a viable option (due wind/terrain/etc).
Whaddayareckon?
The dusk period and resultant skyglow issues are so variable as to defy any attempt at ANOTHER prescriptive restriction or rule. One outcome based rule of thumb that we are going to trial as an SOP is as follows:
"IF the NVG image is washed out AND you feel you have to go in unaided AND you want to turn on the searchlight to help - then you should postphone the landing until dark enough for NVG"
What we are saying is that if the goggle image is too washed out due too much skyglow illum, then you would want to go in unaided. If you make that determination and then subsequently realise you want/need the searchlight on to help pick up detail: postphone landing until it is dark enough for the NVG image.
Obviously, if faced with this situation, an approach away from skyglow was not a viable option (due wind/terrain/etc).
Whaddayareckon?