Hovering in the Dark?
Senis Semper Fidelis
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Hovering in the Dark?
Last evening at about 2250hrs our local area was visited by the Lancashire ASU from Warton, obviously looking for some night workers or nasty person(s), the night was clear a new moon was in the west and it was pretty dark, ASU heli was at about 750ft and hovering absolutely dead still for what seemed like stints of 4 to 6 minutes, then a little move left or forward and then resuming the high hover, again dead still.
After watching this for long enough to get cold I started to think how do you come to a complete standing still hover in the dark,
so for those night Pilots out there, How is it done, if you have no horizon to fix on, is it pure instruments or do you have some sort of auto-pilot that will do this for you?
My regards
Peter R-B
Vfr
After watching this for long enough to get cold I started to think how do you come to a complete standing still hover in the dark,
so for those night Pilots out there, How is it done, if you have no horizon to fix on, is it pure instruments or do you have some sort of auto-pilot that will do this for you?
My regards
Peter R-B
Vfr
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VFR
No instruments or autopilot, just mark one eyeball and hands and feet!
A good moonlit night helps of course, otherwise there has to be some ambient light, even if it's a couple of miles away.
No instruments or autopilot, just mark one eyeball and hands and feet!
A good moonlit night helps of course, otherwise there has to be some ambient light, even if it's a couple of miles away.
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Depending on the aircraft, I'd say NVG and a good AFCS with all the lateral and longitudinal drift trimmed out and probably Radar Altimeter with an altitude hold function.
Takes all the hard work out of the sneaky peak stuff.
CB
Takes all the hard work out of the sneaky peak stuff.
CB
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These days a reliable AFCS with an associated stick trim does the job. In Ac without such luxuries then provided you have perspex by your feet, it's down to forward and lateral references and a good instrument scan.
Gentleman Aviator
And of course the "dead still" at 750ft is probably a bit less so than at 750mm in the daylight. But then it doesn't need to be...
Try that on a deeply dark night...at 2500 feet AGL in a non-sas'ed (sasless) aircraft...for extended periods of time....over a unique spot on the ground....with about 10 feet variance allowed on horizontal movement...and 50 feet vertically...on NVG's. Pointed the FLIR straight down and used the Co-pilot to call drift. Made for some good fun....not...but a real challenge.
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In the Gazelle (no SAS!) during surveillance sorties we use a GPS utilising ground speed, though it doesn't indicate in what sense we are drifting, and placing the toe of your boot on a road junction or hedge-row. Try doing this on NVG in the pi$$ing rain with 20 gusting 30 w/v not to mention the monitor of the surv camera closing down the gogs at flight level nose-bleed! This is why Gazelle jocks are Ninja!!
Purveyor of Egg Liqueur to Lucifer
helidriver,
Surely with a good airflow over the disc it is easier.
I hope at "flight level nose bleed" you are not logging those NVG hours!
SS
Surely with a good airflow over the disc it is easier.
I hope at "flight level nose bleed" you are not logging those NVG hours!
SS
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I use my eyeballs assisted by an outside/instrument/outside scan. If you have a good scan, even with a poor horizon, you can pick up drift. In my past life I hovered over a N Ireland city at 10,000 feet with my NVG lifted up. It was easier without them!! With a little experience, it is not really difficult.
Night motor racing uplink, we used to hover at 2500-3000ft, but there wasn't a lot of lighting apart from the track directly underneath, and Melbourne Airport 5 miles away! The B206 would drift around a little bit, but the worst was to allow any backwards drift and subsequent nose up pitch. Time in the hover varied from 15 to 45 minutes, depending on the race and the number of bingles
Wearing bi focals and glancing down wasn't much cop, either
I guess the most important thing was/is the same as hovering overwater: keep your scan and visual reference point(s) well away from the helicopter, and put a lot of reference out toward the horizon.
Wearing bi focals and glancing down wasn't much cop, either
I guess the most important thing was/is the same as hovering overwater: keep your scan and visual reference point(s) well away from the helicopter, and put a lot of reference out toward the horizon.
Last edited by John Eacott; 13th May 2005 at 08:15.
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No, no. Night air has more lift, because you don't have those photons beating down on the tops of the blades, pushing you down.
Night hovering, especially at altitude, can be tricky, because it's very easy to get into a descent without realizing it while looking outside. It should be done only with a crew, with the PNF keeping a close eye on the instruments.
Night hovering, especially at altitude, can be tricky, because it's very easy to get into a descent without realizing it while looking outside. It should be done only with a crew, with the PNF keeping a close eye on the instruments.
To my knowledge, the only Police ASU using NVG in UK is the Devon and Cornwall one - they are still on an extended 'trial' I believe, having negotiated the need for goggles with the CAA.
Since the introduction of our FLIR/TV turret onto RAF SAR Sea Kings we are doing a lot more high hovering during searches whilst the RadOp uses the FLIR, typically at 1000' over land or water. The main requirement is a visual horizon, with that you can select a hover attitude and then use either doppler or visual markers to assess and correct any drift. One could hover on instruments but that is outside our release to service - if the weather is that bad the FLIR probably won't be much use anyway. NVG help enormously to give a good visual picture to hover on and the AFCS again makes things easier. We can use either rad alt hold or bar alt hold on the Mk3A but not the Mk3 - if it is turbulent the height hold can become a liability as it is not as quick to respond as a human left arm. Good crew cooperation and communication is also essential with the NHP monitoring RoD.
Can it be done without all the gucci kit? yes of course, as helidriver says but tales of disorientation, LTE and VRS abound amongst the crews who have done it - having the right kit to do the job makes it so much less stressfull.
Since the introduction of our FLIR/TV turret onto RAF SAR Sea Kings we are doing a lot more high hovering during searches whilst the RadOp uses the FLIR, typically at 1000' over land or water. The main requirement is a visual horizon, with that you can select a hover attitude and then use either doppler or visual markers to assess and correct any drift. One could hover on instruments but that is outside our release to service - if the weather is that bad the FLIR probably won't be much use anyway. NVG help enormously to give a good visual picture to hover on and the AFCS again makes things easier. We can use either rad alt hold or bar alt hold on the Mk3A but not the Mk3 - if it is turbulent the height hold can become a liability as it is not as quick to respond as a human left arm. Good crew cooperation and communication is also essential with the NHP monitoring RoD.
Can it be done without all the gucci kit? yes of course, as helidriver says but tales of disorientation, LTE and VRS abound amongst the crews who have done it - having the right kit to do the job makes it so much less stressfull.
We hover visually without any need for auto pilot. Our remit is to fly in accordance with CAA regs which states that there must be an appropriate level of visual cues to maintain a hover.
All that is required is a minimum SAS fit. The rest is eyeball. I occasionally glance at my GPS G/S but this doesnt indicate drift direction just movement over the ground.
We are not allowed to fly into 'dark areas' like Snowdonia or the Cumbrian hills et al.
Devon and Cornwall are fully functional NVIS, no trial anymore, Others are going operational as we speak. Within a few years most police units will be fully NVIS effective from take off to landing.
We have been flying NVG for the police observers for 7 years, because they are treated as passengers, there are no regs relating to their use. Pilots are the problem!!!!
VFR: How did you guess 750 feet at night???????????
All that is required is a minimum SAS fit. The rest is eyeball. I occasionally glance at my GPS G/S but this doesnt indicate drift direction just movement over the ground.
We are not allowed to fly into 'dark areas' like Snowdonia or the Cumbrian hills et al.
Devon and Cornwall are fully functional NVIS, no trial anymore, Others are going operational as we speak. Within a few years most police units will be fully NVIS effective from take off to landing.
We have been flying NVG for the police observers for 7 years, because they are treated as passengers, there are no regs relating to their use. Pilots are the problem!!!!
VFR: How did you guess 750 feet at night???????????
Senis Semper Fidelis
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Hi TC,
a little bit of trig, and really good eye for distance, plus the differential between movement and sound!
Vfr
It would be nice if one of the Warton crew could confirm that
a little bit of trig, and really good eye for distance, plus the differential between movement and sound!
Vfr
It would be nice if one of the Warton crew could confirm that
