Night Approaches
 

Any one else notice a unconcious tendancy to pull more aft cyclic on a night approach? (lit or unlit pad)

I went last week, and dound myself around 100FT with AS headed down the tubes.

The only thing I could figure was with reduced references gave me a feeling that I was higher and I would unconciously add more aft than I normally would. (I first believed I wouldn't be doing this in response to reduces references, as that would make me think I'm slow too, which wasn't happening, or at least I wasn't reacting to a perceived slow condition)

Glideslope was not a problem at the time but I could see the issues that could develop being low on AS at that point in an approach.

After discussing it with my CFI and knowing I might be doing that, the next ones were great.

On another point we had a round table discussion, some CFI's and I about altitude and flying, I know why 2k makes me some what uncomfortable in the aircraft unlike a plane, and until Shumpei brought it out I would have never have looked at it this way:

75 kias at 500 ft - > you look and feel like you are doing 75knots.

75 kias at 2k ft or higher - > you feel like you are not moving at all (heck at 3k prepping for VTR demo I felt we were already stopped!), don't get the visual you get lower, wondered if anyone shared that thought.

Anyone have any night time stories of similar nature?

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Marc

To: RW-1

Try referring to your airspeed indicator once in a while. That could help.

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The Cat

RW-1, do you have an 'unconcious tendancy' not to turn the steering wheel of a car enough when you are driving round a curve in the road? No, you look out and relate your position in the road to your hands on the wheel.(If you didn't you would crash the car.)

Do a similar thing in the air.

Unconcious tendancies lead to unconcious bodies.

RW-1,

I haven't done any night flying in helis yet, but this sounds to me like one of those classic cases of spatial disorientation or visual illusions you can get with reduced visibility. Landing accidents in fixed wing aircraft have occurred because in poor visibility acceleration can be perceived as pitching up, causing a tendency to lower the nose, which of course worsens the illusion so that the aircraft flies into the ground. In a helicopter you slow down on the approach; would this be the exact opposite - perceived as pitching down, so you tend to unconsciously pull back. I'm not sure. Interesting though; does anyone else know?

I guess this is another case of trusting your instruments.

(Well done; you may have got us off the R22 discussions :) :) :) )

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Whirly

To fly is human, to hover, divine.

At night there is not only a reduction in visibility, but also in the light quality. Surrounding cultural lighting can be misleading at night as well, or cause glare. Depth perception suffers and as a result more cross-referencing is required.

Flying in Canada, often in very sparsely settled areas, the effects are even more pronounced and often we wind up flying IFR on nights with no cloud.

The safest approach I have found is to treat night VFR like it is ALWAYS marginal VFR and be very careful.

About the altitude, part of the problem is also geting accustomed to a particular height. Students I have had that have never flown seized-wing a/c are less accustomed to the height and like it less. From my military time, we all started on jets and so were never really bothered by it. Its actually a lot of fun to see the world from on high once in a while.

Fly safe, and have fun.

Thanks Heloteacher and Whirly,

Doris: I solicited responses because that is just what one is doing referencing outside. Lack of visual clues at night tend to make you do things you wouldn't do if you had more references. In the case of your turn on the road, what would you do if you can no longer see the edge of the road to reference?
(IMO It's not like driving a car, if I think about moving the steering wheel in a car, I have thought about it, if one thinks in certain heli's about moving the cyclic, you've just moved it enought to affect a change.)

Anyway, as I stated in my post, I corrected my issue, I wanted to see how others were coping with it, and offered the altitude comfortability issue as another topic we could engage in.

Helo, I like altitude too, but boy I was not ready for the wide view, and not having doors likely doesn't help me any :) but I'm up to 2K FT now, and trying to get used to it. Rob my CFI wants to hit 5K one day himself :)

We get a lot of low vis days here, and occasionally I get up at night, I know what you mean going into a sparse lit area, it's like a lack hole, plus I fly on the coast, one side: nice, lit, etc. Other side: ocean, few liners lit, etc. In short - hole.
Every time we go up for night time, at least Doug and Rob have had me do several circles begining out to the ocean to both learn to get a feel for reduced ref's, and I'll tell you it's a confidence builder too!

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Marc

[This message has been edited by RW-1 (edited 03 January 2001).]

I'm reminded of the saying:

"Only Bats and Twats fly at night!"

Unfortunately, I don't appear to be a bat!

Try hovering at 5000 feet (above ground level), looking straight down for a while. That will entertain you.

Hmmmm, hovering at 5K, that would be interesting!

Would have to check the charts though, probably could do it now while its cool, but likely not when we have our normal temps (32-33C )

Met a redheaded **** (8 ona 1-10 scale) last week in stuart when we landed, if that's what up there, boy I want to meet more :)
(was that what you meant?)

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Marc

[This message has been edited by RW-1 (edited 03 January 2001).]

The graph I have (not monitored) shows OGE at 5000 ft and 23 C as okay at 1320 lb, so in theory you're fine. In practice, unless you have some very high terrain (obviously not in FLA) you'll be moving either backwards or forwards and almost certainly descending, so pointless exercise in an R22. Different with rad-alt etc.

Regarding the loss of a/s, that is a very common fault with inexperienced night flyers. During the day you rely on so many subconscious cues to adjust attitude that when you lose them at night or IMC, pitch control can become erratic. Having a small (or none?) ADI, poorly lit won't help at all either. Adding 5 degrees nose up over the normal approach attitude, at night with no horizon,is very difficult to spot unless you are monitoring closely. The rapid washing off of IAS is dramatic though. Try it in daytime from 40 kts, and see how long it takes to get to 0 kts. Then leave the power and watch the rate of descent build up. It's dramatic, and at night and low level it can be a killer. (BTW, don't get yourself into vortex ring recovering from the experiment!).

Flying onshore the effects can be ameliorated often with suburban lighting, roads etc. In remote areas or offshore it can be very easy to fall for it. Night deck landings in total blackness can end in a premature stop several hundred yards short, as the inexperienced pilot pays too much attention to the target and not enough to what's happening to the a/c.

With a/c that involve large attitude changes during the decelerative phase eg S76, you can be fooled by the apparent movement of the target down the windscreen, giving a false impression of overshooting or 'going high'. Obviously this can lead to problems, and the physiological cues can be very powerful, to the extent of disbelieving the instruments.

A particular problem you'll have in the R22 is its lack of cyclic trim, so you are reliant on a pitch attitude being maintained by your hand, rather than the stick being held in a trimmed position. This is where the importance of a good cyclic hand position can manifest itself.

The other phenomenom you may experience is the reverse ie you don't slow down soon enough and go sailing past the target. With no texture cues to gauge your groundspeed, a point source target can seem to remain distant with now change in aspect, until the last moment. Attempting to salvage the approach can then lead to the earlier problem, particularly if you lose sight of the target due to violent flaring.

As someone says above, treat night flying as semi IF, look out when you really have to, look in when you really have to and try to hone your other senses such as hearing. You can normally hear speed loss of that extent, similarly you can hear Nr decay or rise if you are mishandling the collective through overcontrolling. Remember that the a/c does not know it is night, so will require the same approach profiles etc. Don't drag it in slowly in the HV curve.

If in doubt, go round and try again.

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Another day in paradise

[This message has been edited by 212man (edited 03 January 2001).]

[This message has been edited by 212man (edited 04 January 2001).]

RW-1:

Most of the points above are good. You may also want to try a "By the numbers" approach at night to a black hole or single point of light reference. ie:

VTOSS, 500 feet at 1 mile
400 feet at 3/4 mile;
300 feet at 1/2 mile; and
200 feet at 1/4 mile.

This will ensure a 3 degree glidepath to your landing site.

You may also want to do some reading on the effects of night visual illusions.
Knowing the pitfalls is half the battle.

For 212: I'd sure like to see a RADALT that indicates up to 5000 feet! Short of installing a TCAS/GPWS I thought they only went to 2000'.

For Helo Teacher: All night approaches/night flying should be treated as IFR when there is no visible, usable horizon.

Cheers, OffshoreIgor http://www.pprune.org/ubb/NonCGI/eek.gif

Well, mine go up to 2500 ft! I take the point, though some go that high. My point was he'd have a hell of job establishing a hover.

I agree with the numbers and gate bit, definately a good idea if not current even when experienced.

As a point of note, all night flying in the UK is IFR except in controlled airspace when it can be special VFR. It highlights the instrument element of night flying.

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Another day in paradise

Hey 212 ...

Lots of great stuff! I agree on the 5K hovering, in the real world, wouldn't hold it for long, certainly if were at 29-33C (but one can dream right? :) )

No AH on board, we do have one on the inst trainer. but you are purely visual on all the others :)

It's interesting that everywhere else (I believe) night flying is IFR, but here we can go VFR, I love night flying, just have to keep on top of everything.

Tried out the gate numbers offshore provided, worked out even better, now that I know what I was doing before, and using that as a gen guide. Much happier now.

>>A particular problem you'll have in the R22 is its lack of cyclic trim, so you are reliant on a pitch attitude being maintained by your hand, rather than the stick being held in a trimmed position. This is where the importance of a good cyclic hand position can manifest itself.<<

This is what I was referring to earlier, you don't have to do much but think to twitch your cyclic hand and move the nose further than you wanted, but I have found a spot for my hand on the leg/knee to anchor for approach once established, then hand movements only when needed I found works well (I hope you take my meaning there)


Ss for radalts:

AlliedSignal Bendix/King KRA-10A to 2500 FT (indicated)

A lot of the others I've seen also go to 2500

Can't remember if the APN-194 mil radalt went to 5K or not, (I think it did, from 2K to 5K you just had 1K increments, so it wasn't reliable, but would indiate, but I could be off).


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Marc

RW-1
In answer to your question concerning the problems of reducing A/S on night approaches it's quite simple really.(No I'm not being condescending, it really is simple).
Mostly it's down to reduced visual cues. By day there are plenty of these available both consciously and sub-consciously. Loss of depth perception. Peripheral movement cues that disappear, ground rush etc. These are what usually give you a fairly accurate impression of both closing speed and rate/angle of descent. As these are unavailable at night the tendency is often to maintain too high a ground-speed for a given height. Then as you perceive the LS disappearing down the front of the w/screen the automatic response is to use aft cyclic to reduce speed, in a vain attempt to maintain your sight picture and/or to lower the collective with the same aim. This obviously puts you perilously close to the Vortex Ring regime so is often discouraged by instructors!!
A useful technique that avoids this is to adopt that as taught in the military. e.g. 500'/50kts, 400'/40kts, 300'/30kts, etc. It works every time and unlike the solution offered by offshoreigor does not rely on knowing your precise range from the LS.
BTW hovering at 5k is something you get used to, ask any Army Gazelle pilot.
offshoreigor
There are Radalts that read up to 5k, believe me the AN/APN 198 for example.
Oh yes Lu, thanks for a very short if totally unhelpful reply. :)

Couldn't add much more than the good stuff already posted. I agree especially with the 400ft/40kts; 300ft/30kts etc. This works very well in poor weather as something to hang your hat on and encourages the scanning of the ASI which is half of the problem sorted.

We used to be required to hover at up to FL100 in a previous job. No radalt goes that high, although we did have a doppler "along & across" hovermeter for the RHS only. When flying from the LHS we used to watch the digital doppler readout and aim for "all the zeros". We flew at whatever altitude we could get at max. continuous power. All manual stuff, up to 2 and a half hours flight time depending on fuel load. Pretty unreal stuff at times. Improved the IF scan no end, though.

War stories again...sorry!

[This message has been edited by Skycop (edited 04 January 2001).]

Wow! the 5000 feet hovering certainly pricked some egos. I was exaggerating when I said 5000 feet. I did spend a few weeks in a Schweizer 300, with 3 on board, hovering between 2 & 3000, 20 mins at a time for a total of around 5 hours a day, over one of the busiest airports in America. That was hard work, and very cramped.
Remember, hovering means one spot over the ground, not necessarily zero airspeed. If you're not comfortable with OGE hover, do it with an instructor for a while and practice engine failures in that situation.

Well some of us aint exaggerating. Saw a few airliners at close range who didn't know we were there...

Reg C Elley:

Although your Altitude vs Airspeed analogy may work on a good visual night, it does not provide the necessary safe VTOSS (most twin helicopters are 35-45 kts) nor does it give you a very good margin above translational speed, (25-35 kts on most helicopters).

The "by the numbers" approach is designed for offshore approaches to a black hole, based on Radar distancing and provide a sfe flight profile with regards to VTOSS.

If used to an onshore facility, then it is only relevent when the distance back is known, however the approach speed must remain above translational speed at night regardless of distance back so as to avoid an inadvertant OGE hover at an unacceptable altitude.

Unlike the Military, Civil night ops are predicated on a known approach gate. I also know that in the Military, outside of a combat situation, you would not be expected to transition into an unrecenoitered area. At least that was the case in the CF.

Ofcourse if you are equipped with a Night Sun, then it becomes an entirely different story.

My point is, that if you are doing your night approach to a "Rig" type environment or to a "Known" land based helipad, such as a Hospital Pad or established night pad, then the "by the numbers" approach has been proven to be the safest and most effective in eliminating the guess work.

Cheers, OffshoreIgor http://www.pprune.org/ubb/NonCGI/eek.gif



[This message has been edited by offshoreigor (edited 05 January 2001).]

Well this certainly has become a great topic for discussion, which is what I wanted, we have borne out a few types/methods of performing a night approach, dangers involved, etc. I'm pleased!

I believe if I know the distances, I would tend to go with offshore and use "the numbers", (why not? If I know my distance there shouldn't be much of a fudge factor)

When I don't however, the alt/AS seems to be a good substitute gouge for getting myself in the ballpark, as long as I stay atop of any other issues that may arise on the approach.

One thing I do know, the more you do 'em, the better you get at 'em! (shoot, at least I hope so :) )

Oh, and I did check, the 194 will go to 5K, but I've not really seen one that holds there, always locks out sporadically.

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Marc

Offshoreigor - Rw-1 is having problems in an R22 which does not have a radar for precise ranging and, if I am correct, does not even have an artificial horizon as the aircraft is not certified for instrument flying (please correct me if I am wrong RW-1). The method suggested by RegCElley of matching height above the LS with airspeed is far more relevant in the light single engine helicopter - who cares about safe single engine speed when you are in the avoid curve all the way down?
RW-1 you dont say what sort of LS you were making approaches to and what arrangement of lights you were using to judge your approach perspective. The previous advice to scan regularly to the side during your approach to help assess your rate of closure is very valid and will avoid the 100' hover or the screaming jesus final approach.

Crab:

We have already established that RW-1 knows the distances. I think if you recheck your regulations, you will find an 'independant artificial horizon source' is mandatory for night flying. This is the case in Canada and most ICAO countries.

I guess what it boils down to, is what RW-1 is comfortable with and what works best for him.

Cheers, OffshoreIgor http://www.pprune.org/ubb/NonCGI/eek.gif

Crab & Offshore,

Actually, while I didn't state where I was going into (it was coming back to FXE, in which I have a curved approach to a section of taxiway).

My actual post reflected that I had a problem, figured it out that night with my CFI, and wanted others to share their horror stories, and tips they use to combat nightime illusions that can cuase problems, this certainly has occurred! :)

You are correct Crab, for here.

While we can (in the US) do VFR night time, most R-22's have the smaller panel, and while some may have an AH installed there (owner thing), most do not including ours. However there are R-22's with larger panels, I believe they are certified for IFR, certainly we use ours for instrument practice (attitude instrument flying and approaches, that panel makes you feel more like you are in a 206 than a 22 :) )

Hey, never did a screaming Jesus approach yet (remember my issue was getting slow) Is that when the little statue hanging from the WC starts yelling "Whoa!" ?

But I also like the numbers bit too, I'm sure whn getting into mor advanced craft, if I know what they might expect me to use, I'll be familiar with it.

Ahh, more cramming this week, ugh !



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Marc

There are no IFR certified R22's. To be IFR certified, you have to have back up gyro systems along with various other things. It is possible to get an instrument rating in an R22 but flying actual IMC in one would be a very foolhardy thing to do.
Also, for the USA there are no regs requiring any special instruments (fitted in aircraft) for night flight. Depending on location, it's not always necessary. Flying over a busy downtown area for eg. Get away from a built up area and it can quickly feel like IMC. At night for long trips out of area, I used to file IFR flight plans in an instrument equipped Schweizer 300C then cancel near home base so didn't have to do the approach.

Interesting topic. Im sitting in the office in the Virgin Islands(where there arent any) waiting for it to get dark so i can fly some folks out to Peter Island (www.peterisland.com) They are on vacation and Im just going to go scare myself for fun......Kidding
It does get very dark down here in the Islands and this company Bell 206L just loves daylight.
Over the years I have found that the one thing that has kept me from balling one up at night is to take things a lot slower and not to make steep turns. Over water, no moon and Zero Horizon can be real fun...Luckily there is a moon out tonight.....
Stay Safe

please correct me if I am wrong but having sat in what I regarded as a high hover OGE at approximately 6000' in an R22 HP, is this supposed to be impossible. Granted it was in the UK and OAT was 6 degrees C when we took off.
We were practising pirouettes too with zero speed at 5000' but letting the wind turn us!!
If you're gonna go, might as well go having fun!!

No, as I said earlier, the graphs fully support that. What I was trying to say was that in fact if you recreated the same hover at ground level it would look far from tidy in all three 4 axes. Obviously it can be done as anyone with NI or AEW could testify, but needs practice.

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Another day in paradise

I guess I left out a few points, well here goes.

First, if you fly an approach based on an IAS for a given altitude, there is no guarantee that you will fly the same approach twice.

Second, by using the 'by the numbers approach' you will always fly the same glidepath to you LZ (in this case a 3 degree (G/S).

WRT VTOSS, yes it is only applicable to twins, however, if you consider that a single engine has an approach speed that if you go below for a given altitude, then you are S.O.L. if you lose your one stove and are not able to recover airspeed for the impending auto.

So to sum up my reference to VTOSS, a single engine driver can substitute, minimum safe autorotative speed.

To me, a known glidepath to a night site would always be preferable.

By the way, someone said the R22 doesn't have any way to determine distance back, ever heard of GPS?

Cheers, OffshoreIgor http://www.pprune.org/ubb/NonCGI/eek.gif

I agree with you offshore, numbers are preferable as you can always strive for them.

As for GPS, well unless you have a portable, most robbie owners (or more to the point, most training outfits 'round here) don't have it. Heck, I'm flying by pilotage, no VOR even ! :)

Fishboy, If that's true, I stand corrected, I had called to ask if our trainer was certified, but our CFII is out sick. I can go with your statement though.

Helimutt, at least where I was saying the OGE hover at 5K might not be possible was due to regular temps here in south Florida (33-34C). What 212 meant was that keeping a precision hover over a point at that alt takes practice (if I read it correctly)

Still deep into cramming for the test ... http://www.pprune.org/ubb/NonCGI/frown.gif
I'll be so glad when I ace that bugger! (at least that's my plan ...)

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Marc

Offshoreigor - RW-1 is making a visual approach at night to a fixed point (presumably illuminated) so if he flys the LS in the same position in the windscreen and achieves speed v height gates - he will always fly the same approach (providing he is always approaching on the same heading. Trying to maintain minimum safe autorotative speed on a night approach would most likely end up with a quickstop to the hover with all the attendant problems of loss of references as the landing lamp shines upward due to the flare and ground proximity cues are lost completely! Frankly any kind of AI or AH would be better than nothing especially at night over the water - I have scared myself many times there even when I have had an AI to help me!

I think minimum safe auto speed sounds a bit sporting! What speed are we talking about? constant attitude or min rate of descent? It's a bit academic in a single as the minute the donk quits you are no longer going to reach the destination, unlike a twin where Vtoss may well get you there.

I'd advocate the 10% of height=speed routine and suggest it if I see candidates having trouble with night deck landings. (It's not the only way, but it's predicatble and safe)

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Another day in paradise

Actually Crab, the approach in question is straight along a taxiway, however then at 50 Ft or so I follow the curve of that taxiway (rather I am alongside it over the grass) to the next section of taxiway. Hard to describe, Perhaps I'll find a A/D chart online.

Anyway picking up my line of the taxiway is no issue, I was losing the spot as it tends to draw my focal point away from the spot itself. Once I did pick up other things to use it became much easier for that particular approach.

The other one I was doing over in Pompano, was simply along a taxiway to an intersection, very easy to pick out, but in the beginning I succumbed to illusions and was using too much aft cyclic at the time.

I'll know if I have gotten over it the next time I do some night approaches. Hehe ..

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Marc

RW-1 : I have done alot of night approaches to verious kinds pf poorly lit helipads and I have experienced that same thing. You are on the approach every thing feels fine then all of a sudden in the last 1/4 mile it feels like you are over running the pad.This condition is much worse if you have a tail wind.

The method I prefer using is Altitude and Distance. Similiar to Off-shore Igor's technique but I use higher altitudes if flying to an on-shore helipad over rough terrain. I like 800 feet a mile back 400 to 500 feet half a mile back 200 to 300 feet a quarter mile back. Speed; slightly above VTOSS if multi-engine (50-to 60 knots)at the start of the approach.

At 1/4 mile back at 250 feet your airspeed should be slightly above translation and decelerating and don't forget POWER. From this point it is all visual and seat of the pants.

Best to try some of these approaches in day light to get the profile and then try it at night. Be really careful of long shallow approaches on black nights as you can end up flying into the ground (CFIT).

By the way : A continuous decent from 800 feet and 1 nm back to pad impact will result in a glide slope of approximately 7.5 degrees.

Ah! Peter Island – what a glorious place, B Sousa – tried to convince the hotel management that they needed a 206 shuttle when I spent a couple of weeks on holiday there in ’86. Must be a wonderful job!

On the hovering at 5000 ft issue - how’s this for a daft exercise. We were required to do some transponder trials back in the late 70’s at London Heathrow. Requirement was to position a Bo105 on a cold clear NIGHT some 3 miles south of LHR at 500 ft and climb vertically up a searchlight beam to 5000 ft. The ground station at LHR shone a small searchlight at us and we shone one back at them from the open sliding door so they could keep track of our angular elevation with reference to them. We then had to fly south 7 miles sideways at 5000 ft to another searchlight beam which was also pointing vertically upwards, all the time keeping our searchlight on the LHR groundstation. It was February and –13C at top of climb. B****y cold going sideways with the door open!! Needless to say with the lack of any groundspeed info we fell out of the sideways manoeuvre many times. Ah! youth – where did it go……

Tech is quite right about shallow approaches over unlit areas at night – it’s too easy to cock it up, no matter how much experience you have. The “black hole” phenomenon when approaching a lit landing site at night over unlit terrain is well documented. There were photos posted on the PPRuNe R & N forum some months ago of a 707 that flew into the water on a visual night approach over Lake Victoria (I think). Bristow Australia lost a Puma some years back on a night VMC approach to an offshore rig – a very experienced crew flew into the water half a mile from the rig.

In my own case about 20 years ago, with about 30 miles to run to destination, with another experienced pilot as co-pilot, we started a long slow clear night VMC descent in a S76 from FL 50 to the Montrose platform in the North Sea and only realised at about 300ft that we were going into the water about half a mile from the platform. From that moment on, whenever similar descents were envisaged I levelled at 1000 ft for at least a minute before continuing the descent. This seems to break the visual brain pattern that nearly ended in a ditching that night. The problem on a “black hole” approach – especially a shallow one – is that you can be quite convinced that nothing is wrong and that the approach is fine, even with two pilots on board.


[This message has been edited by Speechless Two (edited 09 January 2001).]

Here are some things that that I learned early on and have served me well concerning night approaches

1. Keep your head on a swivel. you must scan to overcome the central night vision blind spot and most of the visual illusions

2. Treat all visual barriers as physical. I the lights on your LZ disappear there is something between you and the LZ.

3. On final limit your rate of descent to 300 fpm or less and your airspeed at or slightly above ETL. (settling)

4. Landing lights are useless above 200' AGL don't turn them on until then and leave them on when you do. They ruin your night vison.

5. Going to an unlit LZ without a serchlight you will be able to detect light at 25 ft and motion at about 15 ft using only the position lights. There is a tendency to drift to the right because of the brighter green light on that side.

6. There is a lag in the radar altimeter.

In re-reading your post the problem with zeroing out your airspeed on a dark night is most likely the result of poor visual refrence coupled with a poor instrument cross check.

Try following the moon cycle. Start night training on full moon nights and work down to lower levels of illumination.

Start by making approaches to fully lit airfields then dim down the lights and finally use no lights at all.

The Australian Puma accident report can be found at http://www.basi.gov.au/acci/wof.htm for those interested, with a full downloadable report.

[This message has been edited by The Nr Fairy (edited 12 January 2001).]

RW-1,

The short answer to your question is yes. It is well documented in my world (Navy Lynx) and I have seen a lot of students exhibit the tendency. We teach pilots to reduce to 60kts ground speed by 500’ overland and 1 mile out for visual ship approaches, 2 miles for GCA. They are “strongly” encouraged to hold the selected airspeed! Between ½ and ¼ mile (depending on experience, wind etc) a gentle deceleration is commenced aiming to arrive at the hover without the need for a large attitude change (bad for the inner ear and forward vis etc).

From an instructors point of view the key to a good night approach is a good visual/instrument scan and faith in the instruments. The most common fault is improper trimming (generally aft) which stuffs speed stability as soon as the pilot relaxes on the cyclic. Second most common is “rubber left arm” where the collective is subconciously raised as altitude reduces with poor references, again only overcome by appropriate visual/instrument scan.

Note: This technique is military and probably breaks a whole load of public transport regs!

Kewl Gray ... Thanks for your input! :)

Night remote area landings
 

Just curious to learn about others experiences and techniques in night approaches to remote landing sites.

We fly single pilot IFR SAR/EMS and at the present time we unfortunately cannot legally use NVG's. As I had previously used NVG in the military it was a real eye opener to have to operate without them.

We have developed a technique that begins with a 100,000 map appreciation of the area and the calculation of a 5nm LSALT around the landing site. We then fly to overhead at IFR en route LSALT and, if visual, identify the LS (we would expect someone on the ground with a light source). If still IMC at 5nm LSALT we would abort the task.

Once the LS is identified it is saved in the GNS and the W/V is established. A circuit pattern is then flown during which we descend to the 5nm LSALT whilst remaining within a 3nm radius to give a 2nm buffer. The co-pilot EHSI 5nm MAP is selected and the pilot EHSI is set to NAV with the course bar used to orientate circuit direction and the FMS needles selected to the LS waypoint.

On Xwind the nightsun is illuminated, angled to 45 degrees down and IAS reduced to 80 kt. On D/W the pre-land checks are completed. Base turn is begun within 3nm, IAS is reduced to 60 kt and the cabin doors are opened so that the rear crew can look out and down.

Final approach is begun at 3nm and the G/S is reduced to 45kt. A ROD of 5-700 fpm is initiated with the aim of being at 0.5nm and 500ft agl. The co-pilot rad alt is set at 500ft and the pilot radalt is incrementally reduced from 1500ft to 300ft. Once the rear crew have visual ground contact the nightsun is elevated for pilot reference and if the crew is happy with the approach it is continued to a high hover before a landing or winching is carried out.

The entire approach is flown with auto pilot coupled and the pilot only takes over when it is known that a safe landing can be carried out. If visual contact with the light source is lost at any time a missed approach is flown back to LSALT. This takes a fair bit of practice and requires a high level of crew co-ordination and trust but seems to work well.

Any other techniques or comments?

Sheesh - that's a bit different to using crossed headlights!

Phil