NVG Operations Offshore

[TheVelvetGlove]

My apologies if this has been dealt with before, but does anyone have experience using NVG's offshore?

I am specifically interested in hearing from those who have flown with them under moon-less or overcast nights offshore- was there sufficient light out there to amplify to produce a horizon?

The training materials that I have read do not go into depth on the subject, and I don't personally know anyone who has left the beach and gone deep with NVG's in a VFR helicopter.

Any and all information will be appreciated.


Thanks.

[ShyTorque]

Check your pm.

[detgnome]

The RAF SARF operate routinely offshore with NVG in the low level (1000' and below) environment. Like any light amplifying device their performance varies with conditions and as you suggest performance on moonless overcast nights can be poor. That said they almost always enhance the capability and safety of operations. In good conditions approaches to vessels and cliffs can be performed with sole reference to NVG, although the automatic systems such as Rad-Alt height holds are still used to reduce cockpit workload. In poorer conditions approaches may be carried out using the ac's radar and full use of the ac automatic systems, but NVG will still be used and often aid in spotting the target earlier or at least aiding SA. Of course in fog they are no use what so ever...!:hmm:

[Turkeyslapper]

Detgnome

I have always wondered...say you are off to winch off a boat in ordinary weather at night. I take it you would launch IFR and at some point let down to the vessel? Are you 'goggled up' for the IFR transit as well, do you do it say at top of descent or would you do the whole procedure unaided?? (Personnaly I guess I would prefer to be aided but I don't know).

Thanks

Turkey

[[email protected]]

Turkeyslapper - for training we practise the IFR procedure a lot and the crew will have the goggles on but with the HP flying on instruments (the NVGs can be flipped up and down on their hinged mount). Our radar allows us to fly below Safety Alt, IMC over the water as long as we don't overfly radar contacts below 1000'.

During the letdown, the NHP (on NVG) would advise visual when he can see the surface and the HP would either continue to the next step height (500' or 200') and then fly on NVG if the conditions were suitable or elect to stay on instruments all the way to the hover. Once the HP is on NVG, the FCS/FPC (autopilot bits) are used to assist, if required, the letdown to the vessel but if conditions are good there is no reason why the HP can't make a visual approach to the boat on NVG.

At all stages we fly with either bar alt or rad hold in for height protection and regardless of IFR or NVG flight use the same check calls during the letdown. We set Bar alts to agree with rad alts at 500' and again at 200' - the Mk 3 engage rad alt at 200', the 3A's have it available (and on manoeuvre) anywhere below 1000'.

If the weather permits, there is no problem with getting airborne, coasting out and letting down on NVG and in this case the pilots are responsible for collision avoidance rather than the radar operator but, since you are effectively flying VFR, this is not a problem.

Once alongside the vessel, the HP will flip up his gogles and revert to white light for the recce and winching whilst the NHP will normally remain on NVG for lookout and in case he needs to fly the aircraft following an engine failure.

[Turkeyslapper]

Hi Crab

Sounds like a bit of flipping up and down of goggles. Forgive the question but why wouldn't the HP just remain goggled up for a winch off a boat?

Happy with the restricted peripheral vision and depth perception issues but if you also used white light wouldn't that help? Also, if an engine failure (or whatever) did occur in that particular situation the HP is surely in a better position to flyaway in a timely fashion without the need for a handover in a potentially high workload situation?

A question from the uneducated.

Cheers

Turkey

[detgnome]

You can winch on goggles but it's generally accepted that you provide a more accurate hover on white light than you do on NVG as they decrease the Field of View, significantly degrade depth perception and detection of small movements is more difficult. However, NVG can give very occasionally give a better hover on very calm nights when you are hovering on water references as they can 'see through' the goldfish bowl conditions and at least allow you to see a horizon. This is not necessarily an SOP though!

[Phrogman]

From the other side of the pond I will tell you that we do things very similarly, the wonders of an exchange program perhaps. Another reasoning to consider is that way off shore over the water at night with no moon or heavy overcast should be considered IMC, and hence no place for a VMC helicopter. NVG's obviously have limitations, and I have plenty of experience where they have presented no horizon...mainly because there was so little light for them to amplify. The US Navy and Coast Guard require such overwater night operations to have two instrument rated pilots.

As previously posted, flipping goggles up and down is sometimes a requirement to accomplish the missions, but it should be pointed out that the practice has also been cited as a causal factor in two nasty crashes that I know of. One in particular where the crew went to unaided on approach to a ship and shortly there after (5 min) entered an unusual attitude and splashed inverted right next to the vessel, nothing wrong with helo.

For Hoisting, I personally don't flip mine up, but vertically raise them to a level or tilt them up to give me more vis under or around them for hoisting and occasionally catch a glimpse of the horizon. This also eliminates the possibility of drawing a crappy goggle mount that will drop them back down in your face at the most untimely of moments...good times there. The safety pilot however, will keep them down and will be watching the instruments as well. For an emergency flyout, I suspect that will be a dual piloted maneuver for a short bit due to the lag time of the flying pilot to switch gears from visual position keeping to swooping away into the black abyss.

If horizon doesn't exist, well there you are wishing you had a HUD attached to those NVG's with an artificial horizon, but you probably won't find such capability in a VFR helo. Those are cool toys, but even then, I found myself maintaining more of an instrument scan than looking at digital info on the tubes. Old habbits...

But my original motivation here is to say that once you go feet wet far enough off shore to lose any ambient light from land, regardless of the forecast, you can easily find yourself with the need for instruments regardless of what is helping your eyes. My advice is to avoid that environment unless you are dual piloted and you both have polished instrument skills.:ok:

[TheVelvetGlove]

Thank you all for your replies.