Safest final approach
SAS- couple of interesting things from that court case.
1. I see that they only suspended the pilot's ATP. Does this mean that his Private and Commecial were still in force? Or, when you get your ATP suspended does that affect *all* of your certs? Never having had any certificate action (yet!) I wouldn't know.
2. The FAA got him for hovering nearly smack-dab in the middle of the H-V shaded area for the 206. I think it's noteworthy that they took into consideration that he didn't have good forced-landing areas underneath him. I think both of these things are important. Perhaps the FAA would not have gone after him so aggressively if: a) the operation wasn't conducted on a weekday when there were so many people around (to complain); b) if he'd had better forced-landing areas underneath; or c) if he was simply making an approach to a site that required operation in the shaded area.
Point taken, though.
The problem with making approaches that avoid the shaded area of the H-V chart is that helicopters typically don't fly out of airports. I don't know about the rest of you, but in my job a full 80% or more of my landings are to off-airport sites that require something other than a textbook "normal" approach.
And even landing at an airport prevents a normal approach. At an uncontolled field, if I "avoid the flow of fixed-wing traffic," (i.e. don't line up with a runway), I'll usually stay as high as possible so as not to fly low over neighboring houses, etc. This sets me up for a steep, perhaps curved approach to a taxiway or some other spot. At tower-controlled airports, sometimes the tower will say, "Remain clear of all runways," which then necessitates the same thing.
It takes deliberate thought. I "stop" and think to myself, "How am I going to get from here to there while not overflying those houses/hangars/airplanes whatever, and ending up into the wind?" I see a lot of pilots who do not seem to give such things much thought.
The truth is that we *do* infringe on the shaded area in most of our approaches. That's just a fact of life. However, I wish the manufacturers had made the edges of the shaded area "fuzzy" intead of a solid dark, impenetrable line-of-death. Because that is how some pilots interpret it.
I think the best bet is to strike a balance between, "NEVER fly in the shaded area!!" and "The H-V curve does not apply on landing." Do what you've gotta do to get the helicopter there, but don't muck around in the shaded area any more than you have to.
1. I see that they only suspended the pilot's ATP. Does this mean that his Private and Commecial were still in force? Or, when you get your ATP suspended does that affect *all* of your certs? Never having had any certificate action (yet!) I wouldn't know.
2. The FAA got him for hovering nearly smack-dab in the middle of the H-V shaded area for the 206. I think it's noteworthy that they took into consideration that he didn't have good forced-landing areas underneath him. I think both of these things are important. Perhaps the FAA would not have gone after him so aggressively if: a) the operation wasn't conducted on a weekday when there were so many people around (to complain); b) if he'd had better forced-landing areas underneath; or c) if he was simply making an approach to a site that required operation in the shaded area.
Point taken, though.
The problem with making approaches that avoid the shaded area of the H-V chart is that helicopters typically don't fly out of airports. I don't know about the rest of you, but in my job a full 80% or more of my landings are to off-airport sites that require something other than a textbook "normal" approach.
And even landing at an airport prevents a normal approach. At an uncontolled field, if I "avoid the flow of fixed-wing traffic," (i.e. don't line up with a runway), I'll usually stay as high as possible so as not to fly low over neighboring houses, etc. This sets me up for a steep, perhaps curved approach to a taxiway or some other spot. At tower-controlled airports, sometimes the tower will say, "Remain clear of all runways," which then necessitates the same thing.
It takes deliberate thought. I "stop" and think to myself, "How am I going to get from here to there while not overflying those houses/hangars/airplanes whatever, and ending up into the wind?" I see a lot of pilots who do not seem to give such things much thought.
The truth is that we *do* infringe on the shaded area in most of our approaches. That's just a fact of life. However, I wish the manufacturers had made the edges of the shaded area "fuzzy" intead of a solid dark, impenetrable line-of-death. Because that is how some pilots interpret it.
I think the best bet is to strike a balance between, "NEVER fly in the shaded area!!" and "The H-V curve does not apply on landing." Do what you've gotta do to get the helicopter there, but don't muck around in the shaded area any more than you have to.
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From someone who's certified helicopters and taught certification techniques.
A couple of points on the HV curve, in the hope of clearing up some misconceptions. For civil helicopters:
For any helicopter with more than 9 passenger seats, the HV curve is a limitation. If it's a twin engine helicopter, the HV curve is for a single engine failure. Less than 9 passengers, the HV curve is in the performance section.
All HV curves have at least two 'parts'. The part from the low hover point to the knee is flown using takeoff power, but no intervention time from engine failure to pilot corrective action. The part above the 'knee' is flown using power for level flight and a one second intervention on the collective before any action is taken.
For the low hover point - the collective only allowed to be raised. During the HV demonstration, you can't lower the collective and then raise it later.
In summary, the HV curve test conditions are not, repeat not valid for an approach and landing situation. The only place you're going to see an engine failure during the approach and landing situation taken into consideration is for Category A profiles.
And if you want more guidance, look into the Advisory Circulars for Part 27 and Part 29 helicopters.
A couple of points on the HV curve, in the hope of clearing up some misconceptions. For civil helicopters:
For any helicopter with more than 9 passenger seats, the HV curve is a limitation. If it's a twin engine helicopter, the HV curve is for a single engine failure. Less than 9 passengers, the HV curve is in the performance section.
All HV curves have at least two 'parts'. The part from the low hover point to the knee is flown using takeoff power, but no intervention time from engine failure to pilot corrective action. The part above the 'knee' is flown using power for level flight and a one second intervention on the collective before any action is taken.
For the low hover point - the collective only allowed to be raised. During the HV demonstration, you can't lower the collective and then raise it later.
In summary, the HV curve test conditions are not, repeat not valid for an approach and landing situation. The only place you're going to see an engine failure during the approach and landing situation taken into consideration is for Category A profiles.
And if you want more guidance, look into the Advisory Circulars for Part 27 and Part 29 helicopters.
Irrespective of how the curve is created, as the mojority of students now a days are mainly PPL levels (with a few going on to become CPs) I will continue to KEEP them out the shaded area for as long as I can...
On a commercial level, it is our jobs to fly in this area a lot of the time, but I'll still keep to one of my first rules learnt...
Stay out of it as long as possible and only go in when neccessary, and then get out again...
There's no need in trying to become a "test pilot" while at work unless you're employed as one.
On a commercial level, it is our jobs to fly in this area a lot of the time, but I'll still keep to one of my first rules learnt...
Stay out of it as long as possible and only go in when neccessary, and then get out again...
There's no need in trying to become a "test pilot" while at work unless you're employed as one.
We taught this profile for approaching:
65-70 kts (auto speed) and descend power (which will vary depending on your weight)
@ 100 ft - 65kts
@ 50 ft - 55kts
@ 10 ft - 40kts
(or there about)
transition back into the hover taxi and then the hover...
This keeps you in a safe flight profile.
The intire approach up until close to losing transition is done keeping the collective quite still and using the cyclic more. Close to when translational lift starts to lessen, start feeding in the collective and the cyclic forward to keep attitude, correct with pedals and hover taxi onto the pad. Remember, this is all done at the airport with lots of open space. Much later on in the training, they will learn about a more steeper approach into a tighter confine, but for this stage of the training, safety is our biggest thing... especially when they start going solo...
65-70 kts (auto speed) and descend power (which will vary depending on your weight)
@ 100 ft - 65kts
@ 50 ft - 55kts
@ 10 ft - 40kts
(or there about)
transition back into the hover taxi and then the hover...
This keeps you in a safe flight profile.
The intire approach up until close to losing transition is done keeping the collective quite still and using the cyclic more. Close to when translational lift starts to lessen, start feeding in the collective and the cyclic forward to keep attitude, correct with pedals and hover taxi onto the pad. Remember, this is all done at the airport with lots of open space. Much later on in the training, they will learn about a more steeper approach into a tighter confine, but for this stage of the training, safety is our biggest thing... especially when they start going solo...
65 kts at 100 ft, not much thinking time for the 10 hour student there. Think the heli has way too much energy at those sort of speeds. You are bordering into quickstop territory there. Also risk overboosting if there is no wind, you are heavy and you try to stop heli from descending and slowing down that quickly.
65 kts at 100 ft, not much thinking time for the 10 hour student there
You are bordering into quickstop territory there
Also risk overboosting if there is no wind
you are heavy and you try to stop heli from descending and slowing down that quickly
Give it a try and see tomorrow if you can. Just don't rush it...
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Have a look at the end of Youtube video I have posted just above. This is a probably a similar approach to that which Flyting has described...
Last edited by Qwikstop; 11th Feb 2010 at 18:08.
Flyting
Sorry that is not a great way of teaching for someone with 10 hours. You are going too quickly at 65 kts ( I presume you mean airspeed here) and 100 ft for a 10 hour pilot. Curious what ROD do you teach at 100 ft ?
Sorry that is not a great way of teaching for someone with 10 hours. You are going too quickly at 65 kts ( I presume you mean airspeed here) and 100 ft for a 10 hour pilot. Curious what ROD do you teach at 100 ft ?
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As part of an airtest check the other day I got the pilot to fly some approaches which he has used use in the UK.
These entailed a 10-15 degree nose up attitude to flare off speed at 100' before entering a CAA to a HLS.
The surprising thing was that he had no idea about the effect of a single engine failure at the apex of an aggressive flare.
So when an engine was failed in the flare he was surprised why even after (harshly) putting the nose down (ITW) he would have crashed.
The aviod curve is there as a guide....harsh changes in attitude at the final stages of an approach are I suggest inadvisable.
The Lynx helicopter has a MINSELF of 65 kts in most hot climates....the effect of an engine failure on finals can be catastrophic...
In my mind the sight picture approach works equally as well for SE as well as ME pilots...
Any thoughts appreciated!
Ralph
These entailed a 10-15 degree nose up attitude to flare off speed at 100' before entering a CAA to a HLS.
The surprising thing was that he had no idea about the effect of a single engine failure at the apex of an aggressive flare.
So when an engine was failed in the flare he was surprised why even after (harshly) putting the nose down (ITW) he would have crashed.
The aviod curve is there as a guide....harsh changes in attitude at the final stages of an approach are I suggest inadvisable.
The Lynx helicopter has a MINSELF of 65 kts in most hot climates....the effect of an engine failure on finals can be catastrophic...
In my mind the sight picture approach works equally as well for SE as well as ME pilots...
Any thoughts appreciated!
Ralph
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"Sixty five knots at 100 feet on approach."
In 2004, when I was taught to fly helicopters at Bell Helicopter by Wayne Brown, Kevin Brandt, Gary Young and all the fine Bell instructor pilots, a normal approach was described as starting at 500 feet agl and 50 knots. You flew a constant glide path and constant deceleration, ultimately arriving at a slow walk to the low hover. There was no mention of avoiding the HV curve on approach. About a week after starting flight training there, I was soloed, and then sent around the Texas countryside in their Jet Rangers doing what you needed to do for your rotorcraft private pilot rating. Prior to being soloed, I had seen touchdown autorotations from takeoff, climb, cruise and approach.
After leaving Bell, I went straight to Canadian Helicopters for a mountain course. Again, never heard anything about avoiding the HV curve on approach, and in fact learned about a flat disk departure and loaded disk approach. It was drummed in to me that a stabilized approach had a loaded disk, and in that way there were no surprises as to power available at the bottom. On mountain approaches, recce passes were at 40, accelerating to 50 in the course reversal. You lived in the slow speed world, so you could observe ground speed and crab, and the disk better be loaded.
In the years since then, and many visits back to Bell, MD and Canadian Helicopters, I haven't heard anything different on avoiding the HV curve on approach. It generally is a question asked at recurrent, with the correct response being the HV curve does not apply on approach. As I reflected on 65 knots at 100 feet today, it just seemed inconsistent with a normal approach, a steep approach or a standard mountain approach.
In case, I was doing something different and not realizing it, I decided to go test it this afternoon. I was flying a 407 at loaded weight under 4,000 pounds here in Alaska. Since with the FADEC operating, it is almost impossible to get the Nr off 100 per cent, I could do almost any maneuver that I wanted on approach trying to stay out of the HV curve or be at 65 knots at 100 feet.
I flew on and off airport, making approaches to the taxiway, to confined areas and flat open meadows. Even with 5-20 knots of wind, I could not be at 65 KIAS at 100 feet, or stay completely out of the HV curve and be on any semblance of normal, steep or mountain approach. The best thing I can say about 65 KIAS at 100 feet is, it is a great profile for an autorotation.
As long as we are on the topic of "safest final approach," why is it that the "operators" are willing to land down wind with 10 or 15 knots on the tail, when an extra 20 seconds of flight could set them up for an into the wind approach. That got me thinking about the HV curve and wind, and I assumed that surely the HV curve was predicated upon no wind or a headwind. Went and dug out the HV curve for the 407 in the RFM, and there was no mention on the chart of wind. Thought surely it must be in the notes but couldn't find it. Called my buddy at Bell, and he explained to me that the HV curve is predicated upon a hard surface, where a helicopter could slide forever, and doesn't need to be zeroed out. My take away from this is while it isn't real bright to depart or land downwind over a runway, if there is an alternative, it is flat out stupid to depart or land downwind over a surface where you need to zero out your ground contact or topple the ship.
In 2004, when I was taught to fly helicopters at Bell Helicopter by Wayne Brown, Kevin Brandt, Gary Young and all the fine Bell instructor pilots, a normal approach was described as starting at 500 feet agl and 50 knots. You flew a constant glide path and constant deceleration, ultimately arriving at a slow walk to the low hover. There was no mention of avoiding the HV curve on approach. About a week after starting flight training there, I was soloed, and then sent around the Texas countryside in their Jet Rangers doing what you needed to do for your rotorcraft private pilot rating. Prior to being soloed, I had seen touchdown autorotations from takeoff, climb, cruise and approach.
After leaving Bell, I went straight to Canadian Helicopters for a mountain course. Again, never heard anything about avoiding the HV curve on approach, and in fact learned about a flat disk departure and loaded disk approach. It was drummed in to me that a stabilized approach had a loaded disk, and in that way there were no surprises as to power available at the bottom. On mountain approaches, recce passes were at 40, accelerating to 50 in the course reversal. You lived in the slow speed world, so you could observe ground speed and crab, and the disk better be loaded.
In the years since then, and many visits back to Bell, MD and Canadian Helicopters, I haven't heard anything different on avoiding the HV curve on approach. It generally is a question asked at recurrent, with the correct response being the HV curve does not apply on approach. As I reflected on 65 knots at 100 feet today, it just seemed inconsistent with a normal approach, a steep approach or a standard mountain approach.
In case, I was doing something different and not realizing it, I decided to go test it this afternoon. I was flying a 407 at loaded weight under 4,000 pounds here in Alaska. Since with the FADEC operating, it is almost impossible to get the Nr off 100 per cent, I could do almost any maneuver that I wanted on approach trying to stay out of the HV curve or be at 65 knots at 100 feet.
I flew on and off airport, making approaches to the taxiway, to confined areas and flat open meadows. Even with 5-20 knots of wind, I could not be at 65 KIAS at 100 feet, or stay completely out of the HV curve and be on any semblance of normal, steep or mountain approach. The best thing I can say about 65 KIAS at 100 feet is, it is a great profile for an autorotation.
As long as we are on the topic of "safest final approach," why is it that the "operators" are willing to land down wind with 10 or 15 knots on the tail, when an extra 20 seconds of flight could set them up for an into the wind approach. That got me thinking about the HV curve and wind, and I assumed that surely the HV curve was predicated upon no wind or a headwind. Went and dug out the HV curve for the 407 in the RFM, and there was no mention on the chart of wind. Thought surely it must be in the notes but couldn't find it. Called my buddy at Bell, and he explained to me that the HV curve is predicated upon a hard surface, where a helicopter could slide forever, and doesn't need to be zeroed out. My take away from this is while it isn't real bright to depart or land downwind over a runway, if there is an alternative, it is flat out stupid to depart or land downwind over a surface where you need to zero out your ground contact or topple the ship.
As I am bored with this just dug out the flight manual for a 500D
This is the quote ref to height vel diagram
" Airspeed/alt combinatins to be avoided in the event of an engine failure during take-off are shown in the height velocity diagram"
Basically there is no diagram for landing, if there were the curves would be much smaller as you are not climbing, you have more forward energy and the pitch angle of the blades is very low therefore much easier and quicker to get into auto.
As a flight examiner I would be seriously worried ( consider failing on safety grounds) if a ppl was trying to land a heli from 100 ft at 65 kts espically in minimal wind.
This is the quote ref to height vel diagram
" Airspeed/alt combinatins to be avoided in the event of an engine failure during take-off are shown in the height velocity diagram"
Basically there is no diagram for landing, if there were the curves would be much smaller as you are not climbing, you have more forward energy and the pitch angle of the blades is very low therefore much easier and quicker to get into auto.
As a flight examiner I would be seriously worried ( consider failing on safety grounds) if a ppl was trying to land a heli from 100 ft at 65 kts espically in minimal wind.
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In answer to the first post.. I say learn the constant angle approach well.. the rest will come later.. The "airfield approach" won't work so well in a field with that hidden cable running across it.
A H/V curve would be different for different collective settings... I imagine the published h/v curves must apply to a collective setting used at t/o and so would be inherently safe through all flight envelopes including landings (obstacles aside!). But the landing envelope would have a much "free-er" h/v curve if a collective position could be defined... it can't though for obvious reasons...
To take extremes...
Vertical autorotation?
40knots constant angle auto?
Perhaps someone more knowledgable could confirm: Constant angle approaches through the H/V shaded areas would surely allow you to drop into autorotation safely at any point?
The point someone made about not making your helipad from a Constant Angle Approach in the event you need to auto... I believe could also apply to
the low /high speed approach.. imagine the extreme that you are 1 mile out on approach low and fast... your k.e wont save you.
yet I can imagine being able to make the spot from a bit high and slow by dropping into a steep auto.. imagine being way to high... you could hypothetically auto into your pad.... e.g from 2000ft above your oil platform...? Certainly not from the shaded area in the H/v curve with high collective....but with a low collective..?
Someone suggested the safest approach is a perfect auto... a little tounge in cheek I assume... so I will go one further..
the safest way of guaranteeing you will make your pad is to be above it.... by vertical auto?
(touch paper lit... standing back
)
(just pre-empting the Vortex Ring comebacks... Of course this is not a practical suggestion....!!!) And by the way... I do wonder about the previous suggestions that you "not worry about VRS if you are 'approaching into wind'".. you never know.. e.g the high ground you thought was flat ahead of the Lz blocks the oncoming and wraps the wind in broadside.. or even behind you..... very common... your fast and low approach might catch you out then too......
Quote:
I'm sure someone will correct me if I'm wrong, But I do not believe the H/V curve only applies at take off.
It would also apply for example, when ever the aircraft is within the shaded areas, right? which can include low flying (for example hovering at 150 feet). You would not, for example approach vertically from 500 feet with zero airspeed, because if you did, you would be within the shaded areas. Therefore the shaded areas of the H/V curve are to be avoided, including whilst landing.
I'm sure someone will correct me if I'm wrong, But I do not believe the H/V curve only applies at take off.
It would also apply for example, when ever the aircraft is within the shaded areas, right? which can include low flying (for example hovering at 150 feet). You would not, for example approach vertically from 500 feet with zero airspeed, because if you did, you would be within the shaded areas. Therefore the shaded areas of the H/V curve are to be avoided, including whilst landing.
To take extremes...
Vertical autorotation?
40knots constant angle auto?
Perhaps someone more knowledgable could confirm: Constant angle approaches through the H/V shaded areas would surely allow you to drop into autorotation safely at any point?
The point someone made about not making your helipad from a Constant Angle Approach in the event you need to auto... I believe could also apply to
the low /high speed approach.. imagine the extreme that you are 1 mile out on approach low and fast... your k.e wont save you.
yet I can imagine being able to make the spot from a bit high and slow by dropping into a steep auto.. imagine being way to high... you could hypothetically auto into your pad.... e.g from 2000ft above your oil platform...? Certainly not from the shaded area in the H/v curve with high collective....but with a low collective..?
Someone suggested the safest approach is a perfect auto... a little tounge in cheek I assume... so I will go one further..
the safest way of guaranteeing you will make your pad is to be above it.... by vertical auto?(touch paper lit... standing back
)(just pre-empting the Vortex Ring comebacks... Of course this is not a practical suggestion....!!!) And by the way... I do wonder about the previous suggestions that you "not worry about VRS if you are 'approaching into wind'".. you never know.. e.g the high ground you thought was flat ahead of the Lz blocks the oncoming and wraps the wind in broadside.. or even behind you..... very common... your fast and low approach might catch you out then too......
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On the Lynx, during the bad engine MTBF period, we applied, if runway lenght above 1200 ft, 100 ft/ 100 Kt at threshold, then collective fully down, nose up to 10-12 in a slow descent until speed decreases toward O then hover attitude and touch down. It was funny. Kind of horizontal autorotation.
DO
DO
With all this talk of approach and departure angles, I looked in my files and found this from a post some time ago:
One good way is to stand at the landing point, extend your arm out in front of you to and bend your wrist so that your palm is facing you at eye level. Put the lowest finger on the horizon, parallel with it, and count the number of fingers up until the obstacle is cleared. Each finger is about 3 degrees, so 4 fingers gives you your 12 degrees. You can also do this sitting in the cockpit to judge climb out power requirements.
Another good trick is to extend your left leg to your left side about shoulder width away from your normal standing position. As you shift your weight onto your left leg, violently shift your right leg forward at least 3 feet with your head down. From this position, gently extend your right arm. When fully extended, clench your fist, grit your teeth, look up and extend your middle finger. This is how to greet a fixed wing pilot.
Another good trick is to extend your left leg to your left side about shoulder width away from your normal standing position. As you shift your weight onto your left leg, violently shift your right leg forward at least 3 feet with your head down. From this position, gently extend your right arm. When fully extended, clench your fist, grit your teeth, look up and extend your middle finger. This is how to greet a fixed wing pilot.
