Why do choppers fly so low?
To be fair....there is not much to run into in that part of Arizona.
I would doubt that many have had a lot of practice with an auto at low-level.
It is easy to say it is a non-event because the curve says its fine.
Pulling it off over uneven, rugged terrain could be an interesting experience.
Apart from a fear of heights, they fly low because it is cool and creates an experience, not because it is wise to do so
It is easy to say it is a non-event because the curve says its fine.
Pulling it off over uneven, rugged terrain could be an interesting experience.
Apart from a fear of heights, they fly low because it is cool and creates an experience, not because it is wise to do so
Thread Starter
Correct, they were not throwing it around. I thought the whole operation was v professional and well organized.
Megan,
Memory serves me that we were taught that technique less the 360 degree pedal turn after an authoritative landing....although upon hearing of it....did have to try it ourselves.
We did a great number of practice autorotations and practice EOL's to the ground from all sorts of heights and airspeeds.
We did so because it was accepted Huey Pilots would need that particular skill in their upcoming tours in Vietnam where engines frequently ceased operating for many reasons.
At one point we had unofficial competitions to see who could land nearest a designated point and also who could slide the furtherest at the Stage Field runway.
During conversion to the Chinook we also did autorotations but not to the extent we did with the Huey, Cobra, Loach.
Memory serves me that we were taught that technique less the 360 degree pedal turn after an authoritative landing....although upon hearing of it....did have to try it ourselves.
We did a great number of practice autorotations and practice EOL's to the ground from all sorts of heights and airspeeds.
We did so because it was accepted Huey Pilots would need that particular skill in their upcoming tours in Vietnam where engines frequently ceased operating for many reasons.
At one point we had unofficial competitions to see who could land nearest a designated point and also who could slide the furtherest at the Stage Field runway.
During conversion to the Chinook we also did autorotations but not to the extent we did with the Huey, Cobra, Loach.
"Just a pilot"
Never happened, it's a rule of thumb. I wasn't often in a helicopter with two hours of usable fuel? I can't remember ever being so more than a couple times in 48 years.
The idea is to run a turbine at max continuous for efficiency and minimize drag, yes? Often I could climb to better winds and reduce power and still have a significant gain in ground speed. You never find that poking around contour or at 300, 500 feet. Plus, I could see a lot further, reduced potential obstacles significantly and expanded emergency landing selection geometrically.
I did it like this, half in cruise half in climb or descent- a 40 minute leg, a 4000 foot climb limit: climb at 600 fpm checking speed across the ground on the GPS; then level and cruise at nearest recommended cruise altitude for 20 minutes, checking ground speed and adjust as necessary for most efficient altitude; plan the descent for 300 fpm at whatever speed I could get at cruise power- this offsets the reduced speed in the climb segment. If you're flying into significant headwind component, adjust as necessary, usually lower is better. But I have gotten tailwinds on both in-bound and out-bound legs by flying over the scattered to broken of a weak front. Everybody else poking around in 3 - 5 mile vis while I'm CAVU on the one leg.
The practical limits were weather, of course, and engine/airframe capability. The Allison 250 C20 and contemporary airframes maxed at about 4500 DA, so you'd get the best out of them at that or lower. One might get better ground speed with higher and reduced power, one doesn't know without looking.
The idea is to run a turbine at max continuous for efficiency and minimize drag, yes? Often I could climb to better winds and reduce power and still have a significant gain in ground speed. You never find that poking around contour or at 300, 500 feet. Plus, I could see a lot further, reduced potential obstacles significantly and expanded emergency landing selection geometrically.
I did it like this, half in cruise half in climb or descent- a 40 minute leg, a 4000 foot climb limit: climb at 600 fpm checking speed across the ground on the GPS; then level and cruise at nearest recommended cruise altitude for 20 minutes, checking ground speed and adjust as necessary for most efficient altitude; plan the descent for 300 fpm at whatever speed I could get at cruise power- this offsets the reduced speed in the climb segment. If you're flying into significant headwind component, adjust as necessary, usually lower is better. But I have gotten tailwinds on both in-bound and out-bound legs by flying over the scattered to broken of a weak front. Everybody else poking around in 3 - 5 mile vis while I'm CAVU on the one leg.
The practical limits were weather, of course, and engine/airframe capability. The Allison 250 C20 and contemporary airframes maxed at about 4500 DA, so you'd get the best out of them at that or lower. One might get better ground speed with higher and reduced power, one doesn't know without looking.
I have done the low road and high road method....usually the high road was for cooler OAT or to get above bad vis.
For long transits....Wind was also an issue as with a tailwind it took less total fuel to meet fuel requirements thus more payload for passengers and baggage.
Some routes were pushing 250nm one way plus having IFR fuel reserves for an on-shore diversion.
Otherwise....500-1500 feet all worked fine.
I once made a ferry flight from Deadhorse, Alaska to Lafayette, Louisiana and never got over 300 feet for the majority of the flight.
My basic rule was fly high enough to have a decent forced landing site within autorotation range....if at all possible.
If there was no where to land....then it really did not matter so long as you had time to get a radio call off.
For long transits....Wind was also an issue as with a tailwind it took less total fuel to meet fuel requirements thus more payload for passengers and baggage.
Some routes were pushing 250nm one way plus having IFR fuel reserves for an on-shore diversion.
Otherwise....500-1500 feet all worked fine.
I once made a ferry flight from Deadhorse, Alaska to Lafayette, Louisiana and never got over 300 feet for the majority of the flight.
My basic rule was fly high enough to have a decent forced landing site within autorotation range....if at all possible.
If there was no where to land....then it really did not matter so long as you had time to get a radio call off.
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cooperplace,
I used to fly this trip at the Bar 10 about 18 years ago. It was a favorite job for us pilots; and the Bar 10 folks were some of the nicest people I ever met in my life. Some things may have changed since then, but I suspect very little has.
If you think back you'll probably realize that you weren't just low, you were close to the canyon walls (both the Grand Canyon and the smaller side canyons leading up to the Bar 10 airstrip), probably on the right-hand side. The reasons for this are:
1. In my time we usually ran this operation with two B206B's. When one was on the ground (sandbar on the river shore) at the bottom of the Grand Canyon, picking you up, the other one should be on the ground at the Bar 10 ranch, dropping the passengers he'd picked up 8 minutes earlier, and vice versa. So during the trip between the ranch and the river you'd meet somewhere, head-on. To avoid Bad Things Happening, besides co-ordinating our movements by radio contact, we'd both keep to the right side of the canyon for lateral separation.
2. There were no safe places to land, even fully under control, between the sandbank where you were picked up and the start of the airstrip. Helicopters need a level place to land or they'll roll over; the whole area between the end of the airstrip and the river is one big slope, varying between steep and sheer. If you'd try and land here the rollover would probably only end on arrival at the river. So if the engine quits while climbing up these side canyons your only chance is to turn around immediately to try an autorotation glide down to a sandbar at the river shore. You need room to turn around, you make that room by remaining to the side of the canyon.
There were some other considerations to do with avoiding abusing the Grand Cayon SFRA rules and keeping the noise localized but they were secondary.
And with the above reasons why one should fly low, one cannot disagree with Georg1na and diginagain...
I used to fly this trip at the Bar 10 about 18 years ago. It was a favorite job for us pilots; and the Bar 10 folks were some of the nicest people I ever met in my life. Some things may have changed since then, but I suspect very little has.
If you think back you'll probably realize that you weren't just low, you were close to the canyon walls (both the Grand Canyon and the smaller side canyons leading up to the Bar 10 airstrip), probably on the right-hand side. The reasons for this are:
1. In my time we usually ran this operation with two B206B's. When one was on the ground (sandbar on the river shore) at the bottom of the Grand Canyon, picking you up, the other one should be on the ground at the Bar 10 ranch, dropping the passengers he'd picked up 8 minutes earlier, and vice versa. So during the trip between the ranch and the river you'd meet somewhere, head-on. To avoid Bad Things Happening, besides co-ordinating our movements by radio contact, we'd both keep to the right side of the canyon for lateral separation.
2. There were no safe places to land, even fully under control, between the sandbank where you were picked up and the start of the airstrip. Helicopters need a level place to land or they'll roll over; the whole area between the end of the airstrip and the river is one big slope, varying between steep and sheer. If you'd try and land here the rollover would probably only end on arrival at the river. So if the engine quits while climbing up these side canyons your only chance is to turn around immediately to try an autorotation glide down to a sandbar at the river shore. You need room to turn around, you make that room by remaining to the side of the canyon.
There were some other considerations to do with avoiding abusing the Grand Cayon SFRA rules and keeping the noise localized but they were secondary.
And with the above reasons why one should fly low, one cannot disagree with Georg1na and diginagain...
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One thing that I don't think anyone mentioned is that flying low is good for avoiding the flow of fixed wing traffic. Obviously we aren't talking 30 or 50 ft AGL, or even 300-500 ft AGL. But certainly 500-1000 ft AGL is a very comfortable place to be. High enough to make finding a spot for an auto easier, high enough to avoid most wires and other obstructions, theoretically high enough to avoid UAVs, more friendly from a noise point of view, but lower than most all fixed wing aircraft.
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Thread Starter
I also enjoyed the Twin Otter flight out, in every way. It's nice to be having lunch in the restaurant, and the flight crew, dining at the next table, say "relax, take your time, the plane can't leave without us". It's also nice to not have an armored door separating pax from cockpit.
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I don't fully understand the helicopter pilots' preference for flying low either, but I believe these are the reasons:
1) Fun/cool/it's what the machines do well
2) Staying away from fixed wing traffic
3) Less distance to fall if something goes catastrophically wrong (tail rotor failure, blade delamination, fire, tail boom comes off, etc etc, not just an engine failure-autoration)
4) Glide distance at a few thousand AGL in auto rotation is not great anyway, so you're not giving yourself too many more landing site options at higher altitude
5) Less time in auto-rotation means less chance of the blade stall while you come down? A momentary lapse of attention to RPM in an auto rotation might be more likely if it takes several minutes
6) in Robinsons anyway, you don't lean the fuel mixture in flight so I guess the fuel consumption advantage is not there as in a fixed wing where mixtures are leaned at high altitudes
1) Fun/cool/it's what the machines do well
2) Staying away from fixed wing traffic
3) Less distance to fall if something goes catastrophically wrong (tail rotor failure, blade delamination, fire, tail boom comes off, etc etc, not just an engine failure-autoration)
4) Glide distance at a few thousand AGL in auto rotation is not great anyway, so you're not giving yourself too many more landing site options at higher altitude
5) Less time in auto-rotation means less chance of the blade stall while you come down? A momentary lapse of attention to RPM in an auto rotation might be more likely if it takes several minutes
6) in Robinsons anyway, you don't lean the fuel mixture in flight so I guess the fuel consumption advantage is not there as in a fixed wing where mixtures are leaned at high altitudes
Sometime been asked by ATC to fly a bit higher so they can see me on the radar.
As as civilian pilot, Have any of you flown low enough to avoid radar coverage on purpose?
As as civilian pilot, Have any of you flown low enough to avoid radar coverage on purpose?
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I know quite a few helicopter pilots who are just afraid to fly higher than 500ft. I personally have worked my way up (yes, I am afraid of heights). Been there, done that, 14'000ft in a R22. Looking down between my feet was scary but one gets used to it. In Alaska, everybody flies at 500ft, therefore I decided flying at 3000 feet is much saver and you get a better view.
Well, still hurts and you are dead anyway. No, that isn't a reason.
It is pretty much impossible to stall the rotor in an autorotation, once you pushed the collective down. After all it windmills. Overspeed is more likely but who cares about the blades as long as they bring you down.
Also, been there, done that. You can lean an R22. It makes sense when you work high up. Just land somewhere, lean, take off again and don't do it in flight. Never, ever, ever. And don't forget to PUSH the mixture all the way in, when you come down again.
Apart from long ferry flights, the fuel consumption would not change a lot anyway but performance changes quite a bit.
3) Less distance to fall if something goes catastrophically wrong (tail rotor failure, blade delamination, fire, tail boom comes off, etc etc, not just an engine failure-autoration)
5) Less time in auto-rotation means less chance of the blade stall while you come down? A momentary lapse of attention to RPM in an auto rotation might be more likely if it takes several minutes
6) in Robinsons anyway, you don't lean the fuel mixture in flight so I guess the fuel consumption advantage is not there as in a fixed wing where mixtures are leaned at high altitudes
Apart from long ferry flights, the fuel consumption would not change a lot anyway but performance changes quite a bit.
Thread Starter
I guess it's also quicker to fly low. Our 8-minute flight would have taken longer if there was additional ascent+descent? And time's money, especially with a chopper.
I know quite a few helicopter pilots who are just afraid to fly higher than 500ft. I personally have worked my way up (yes, I am afraid of heights). Been there, done that, 14'000ft in a R22. Looking down between my feet was scary but one gets used to it. In Alaska, everybody flies at 500ft, therefore I decided flying at 3000 feet is much saver and you get a better view.
Well, still hurts and you are dead anyway. No, that isn't a reason.
It is pretty much impossible to stall the rotor in an autorotation, once you pushed the collective down. After all it windmills. Overspeed is more likely but who cares about the blades as long as they bring you .
Also, been there, done that. You can lean an R22. It makes sense when you work high up. Just land somewhere, lean, take off again and don't do it in flight. Never, ever, ever. And don't forget to PUSH the mixture all the way in, when you come down again.
Apart from long ferry flights, the fuel consumption would not change a lot anyway but performance changes quite a bit.
Well, still hurts and you are dead anyway. No, that isn't a reason.
It is pretty much impossible to stall the rotor in an autorotation, once you pushed the collective down. After all it windmills. Overspeed is more likely but who cares about the blades as long as they bring you .
Also, been there, done that. You can lean an R22. It makes sense when you work high up. Just land somewhere, lean, take off again and don't do it in flight. Never, ever, ever. And don't forget to PUSH the mixture all the way in, when you come down again.
Apart from long ferry flights, the fuel consumption would not change a lot anyway but performance changes quite a bit.
Performance improves or reduces with leaning?
What do you think? Would not make a lot of sense to lean to loose performance.
No, actually not, it isn't a tip at all, just a fact. Many R22s out there that live at higher altitudes are always leaned. No big deal, if you know what you are doing. The thing is with leaning, that without precise engine instruments, you lean until the engine starts to run rough and then go back a bit, until it runs smooth again (no RoP or LoP here). Right after "rough" comes silence. I don't want that in flight. The R22 does not have a mixture control where I can turn the knob to fine tune, either. The H300 does have it, I think. Still, even in a H300, land for leaning. It is just the way to do it, on the ground, not in flight. The one thing not to forget, is enriching the mixture again, when going down - below the altitude you landed for leaning - otherwise the donk stops. That is the reason, why leaning is not in the POH of the R22. There are different opinions on that matter, some say the effect on power is marginal. For me it was hovering or running take off. Also the spark plugs like it better and you get a cleaner combustion.
Disclaimer: Don't do it!
It is something you learn with experienced instructors, not something you try on a Sunday afternoon just for the fun of it.
And again: Full rich when going below the altitude you leaned at.
Anyway, Robinson should have gone for fuel injection a long time ago.
The R22 isn't a lot of fun to fly at higher altitudes. Around 60 knots is all you get. A bit too fast and it starts to vibrate from RBS, a bit too slow you sink. With an instructor we tried to autorotate from 12'000 ft. For some reason, it started to vibrate like a wet dog coming home. We suspected some rigging problem, because that ship had no problems at lower altitudes.
I don't like running take offs, but if you can hover at just a few centimetres, you can also take of without touching the ground.
One of those “don’t try this at home” tips, I guess.
Disclaimer: Don't do it!
It is something you learn with experienced instructors, not something you try on a Sunday afternoon just for the fun of it.
And again: Full rich when going below the altitude you leaned at.
Anyway, Robinson should have gone for fuel injection a long time ago.
The R22 isn't a lot of fun to fly at higher altitudes. Around 60 knots is all you get. A bit too fast and it starts to vibrate from RBS, a bit too slow you sink. With an instructor we tried to autorotate from 12'000 ft. For some reason, it started to vibrate like a wet dog coming home. We suspected some rigging problem, because that ship had no problems at lower altitudes.
I don't like running take offs, but if you can hover at just a few centimetres, you can also take of without touching the ground.
