You never know who's watching - Lesson #27 - Helo Water Landings
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There were not in vortex ring state. The Blackhawk requires a rate of descent in excess of 1000fpm to get into vortex ring.
I have not said it was VRS just that settling with power is the US term for this. I would, however, agree with Turtles comments as to the most likely cause.
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Whatever the cause of this incident, what is the procedure for getting out of a Vortex Ring state? Apart from not getting into it in the first place!
Are some helicopters more prone to VR than others?
Thanks.
Are some helicopters more prone to VR than others?
Thanks.
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Vortex Ring State
Howdy all,
I have 2000+ hours in several different H-60 varients including the Fire Hawk. I think that Tailspin Turtle is pretty much on the mark. I would like to have seen a few more seconds of video to see how they "set themselves up" for this.
I can assure you that Vortex Ring State and Settling with Power are the same thing. I have settled with power in an H-60, with a water bucket under slung, while going in to a river canyon dip site. To develop vortex ring state you need to have some power applied %10-15 or so, a fair rate of descent, and little relative airspeed. This causes an induced flow ring state that demands more and more power to arrest descent. As the pilot pulls more power, he exacerbates the situation as the ring grows and eats up even more lift. The cure is to increase airspeed (fly out of) the condition. But you are in big trouble if you have not left yourself any options....
The helo in the video is spinning to the right. Sikorskys are Russian helos with the blades going counter clockwise requiring left pedal input at high power settings. When you "droop" the rotor, and have full left pedal applied, she will rotate to the right until you solve the problem.
On a side note, it can be problematic to hover way out in the water away from any visual reference points. We try to dip near the shore to prevent this. You also don't have to swim so far if you go into the drink.
Damn Navy pilots..... just kidding....
I have 2000+ hours in several different H-60 varients including the Fire Hawk. I think that Tailspin Turtle is pretty much on the mark. I would like to have seen a few more seconds of video to see how they "set themselves up" for this.
I can assure you that Vortex Ring State and Settling with Power are the same thing. I have settled with power in an H-60, with a water bucket under slung, while going in to a river canyon dip site. To develop vortex ring state you need to have some power applied %10-15 or so, a fair rate of descent, and little relative airspeed. This causes an induced flow ring state that demands more and more power to arrest descent. As the pilot pulls more power, he exacerbates the situation as the ring grows and eats up even more lift. The cure is to increase airspeed (fly out of) the condition. But you are in big trouble if you have not left yourself any options....
The helo in the video is spinning to the right. Sikorskys are Russian helos with the blades going counter clockwise requiring left pedal input at high power settings. When you "droop" the rotor, and have full left pedal applied, she will rotate to the right until you solve the problem.
On a side note, it can be problematic to hover way out in the water away from any visual reference points. We try to dip near the shore to prevent this. You also don't have to swim so far if you go into the drink.
Damn Navy pilots..... just kidding....
Below the Glidepath - not correcting
Thread Starter
Initial results of the inquiry are pointing to the incident being caused primarily by the large knob between the cyclic and the collective.
Reduce power, lower the nose, gain airspeed and fly away. Now try that from a 10' hover.
Whatever the cause of this incident, what is the procedure for getting out of a Vortex Ring state? Apart from not getting into it in the first place!
Chief Bottle Washer
Deja vu, all over again
Back in 2002, Blackhawk accident was NOT settling with Power thread elicited a lot of knowledgeable discussion over in Rotorheads.
Nick Lappos' contributions are well worth reading, particularly Post #9:
For the non rotary peeps, Nick Lappos was then a very senior test pilot with Sikorsky, and is now a Director of Bell Helicopters' 'skunk works'.
He knows what he's talking about
Nick Lappos' contributions are well worth reading, particularly Post #9:
Blenderpilot,
I have to agree with squirrel. You and sultan are mixing up the fundamental problem of having too little power with the other aerodynamic condition specifically related to reingestion of the downwash known as Vortex Ring State or settling with power.
What I think you are concerned about is a true issue for pilots - the behavior of the machine when you are severely performance limited. That causes most helicopter accidents that occur on landing, is especially a problem at altitude and high temperature, and has nothing at all to do with settling with power.
It is a very common mistake for pilots to lump these things together, and it is passed from instructor to student as gospel, but it is still wrong.
In the case you describe, the engine power available is very little more than the hover power required, so there is almost nothing left to maneuver. Any disturbance, or any downdraft can absorb all the extra power that you have, and you will descend. That is because you don't have the power to climb, since there is no more power left. Most landing accidents at altitude are caused by this. You are right to be concerned if it is glossed over.
However, that is NOT Vortex Ring State, and it is NOT settling with power. To get into VRS, the rotor must descend fast enough to catch up with its downwash. That speed DOES depend on the disk loading, and that rate of descent IS around 2500 feet per minute for a Black Hawk. The downwash speed of an H-60 is about 45 knots, which is about 4500 feet per minute. At about half that rate of descent, the inboard sections of the rotor are eating up wash, and not producing any down wash. No downwash, no lift. THAT is settling with power. For a Huey, with half the disk loading of a Hawk, you get the first nibbles of VRS at about 1200 fpm rate of descent.
The reason why this is important is that you can't go around teaching folks that some mysterious stuff happens to the rotor at altitude, with moderate rates of descent. You must teach them that at altitude with moderate rates of descent, if you don't have enough power, you will get painted into a corner you can't climb out of, and the earth will smite you.
If you think a downdraft can cause VRS or settling with power, you are on the wrong page! That downdraft is dangerous, I agree, if you are in a heavy helo with little excess power, but that has nothing to do with settling with power.
I can mail you some charts and pictures and stuff, or post them on the web to discuss this more fully, if you'd like.
I have to agree with squirrel. You and sultan are mixing up the fundamental problem of having too little power with the other aerodynamic condition specifically related to reingestion of the downwash known as Vortex Ring State or settling with power.
What I think you are concerned about is a true issue for pilots - the behavior of the machine when you are severely performance limited. That causes most helicopter accidents that occur on landing, is especially a problem at altitude and high temperature, and has nothing at all to do with settling with power.
It is a very common mistake for pilots to lump these things together, and it is passed from instructor to student as gospel, but it is still wrong.
In the case you describe, the engine power available is very little more than the hover power required, so there is almost nothing left to maneuver. Any disturbance, or any downdraft can absorb all the extra power that you have, and you will descend. That is because you don't have the power to climb, since there is no more power left. Most landing accidents at altitude are caused by this. You are right to be concerned if it is glossed over.
However, that is NOT Vortex Ring State, and it is NOT settling with power. To get into VRS, the rotor must descend fast enough to catch up with its downwash. That speed DOES depend on the disk loading, and that rate of descent IS around 2500 feet per minute for a Black Hawk. The downwash speed of an H-60 is about 45 knots, which is about 4500 feet per minute. At about half that rate of descent, the inboard sections of the rotor are eating up wash, and not producing any down wash. No downwash, no lift. THAT is settling with power. For a Huey, with half the disk loading of a Hawk, you get the first nibbles of VRS at about 1200 fpm rate of descent.
The reason why this is important is that you can't go around teaching folks that some mysterious stuff happens to the rotor at altitude, with moderate rates of descent. You must teach them that at altitude with moderate rates of descent, if you don't have enough power, you will get painted into a corner you can't climb out of, and the earth will smite you.
If you think a downdraft can cause VRS or settling with power, you are on the wrong page! That downdraft is dangerous, I agree, if you are in a heavy helo with little excess power, but that has nothing to do with settling with power.
I can mail you some charts and pictures and stuff, or post them on the web to discuss this more fully, if you'd like.
He knows what he's talking about
What a fantastic statement. So have you downloaded the data recorder to confirm this? How many hours MH-60 do you have and at what Hd and airspeed is that 1000fpm correct? My point here is that you are coming across as a know-it-all and i'm afraid you don't.
To get into VRS, the rotor must descend fast enough to catch up with its downwash. That speed DOES depend on the disk loading, and that rate of descent IS around 2500 feet per minute for a Black Hawk.
Nick also highlighted the folly of the term 'settling with power' to describe VRS but that appears to be the way it was taught in the US Mil for many years.
Nick's description shows that the Blackhawk in the vid could not possibly be in VRS or 'settling with power' - he just failed to appreciate his actual power requirements (within normal limits) to come to the hover at high DA - at the point he hit the water he will have pulled very hard past any engine or transmission limits to get back into the air. Very lucky the TR survived the impact.
Nick's description shows that the Blackhawk in the vid could not possibly be in VRS or 'settling with power' - he just failed to appreciate his actual power requirements (within normal limits) to come to the hover at high DA - at the point he hit the water he will have pulled very hard past any engine or transmission limits to get back into the air. Very lucky the TR survived the impact.
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Crab
"at the point he hit the water he will have pulled very hard past any engine or transmission limits to get back into the air"
Not necessarily true. Once he was in ground effect he may have had a lot more power spare.
As the waterbird course shows, you don't need enough power to hover to get airborne from the water, though I'll accept that they did not use those techniques.
"at the point he hit the water he will have pulled very hard past any engine or transmission limits to get back into the air"
Not necessarily true. Once he was in ground effect he may have had a lot more power spare.
As the waterbird course shows, you don't need enough power to hover to get airborne from the water, though I'll accept that they did not use those techniques.
Sikorskys are Russian helos with the blades going counter clockwise
Sikorsky helicopters are American helicopters. Igor (RIP) set up shop some decades ago in New York and Connecticut. I think you will find that American helicopters made by Bell, Boeing, and Sikorsky all have rotors going counter-clockwise. (Not sure about Robinson, but I think they do as well). IIRC, many of the Euro (French is all I can recall at the moment) have them going clockwise so you use different rudder for adding power. Memory hazy on that ...
I see that the usual fun with power settling and settling with power is afoot. (Possibly ill coined phrases, but that was what I got taught way back when in Hueys ... )
From the SH-60 flight manual, same as I used to teach (*cough* how many years was it?) years ago ...
Excerpts from:
11.5.1 Vortex Ring State
The term “power settling” comes from pilot observations that the helicopter keeps settling even though full engine power is used.
The effect is measurable at descent rates greater than 700 fpm and airspeeds between 0 and 20 KIAS and is the worst at descent rates of approximately 1,500 fpm with airspeeds of 5 to 10 KIAS.
11.4.10 Power Required Exceeds Power Available (PREPA?)
At high density altitudes, high gross weights, or when operating with reduced power, power required may exceed power available.
EDIT: Senior Pilot, how did I miss your post? Nick's discussion relates to (I am guessing) UH-60A? Seahawk tends to begin at about 2K heavier than Blackhawk, but his point about vertical speeds of rotor wash means that the flight manual may have deliberately fudged the numbers on the conservative side as a cue to avoid getting into VRS ... interesting.
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To Lonewolf_50: I meant "Russian" in a somewhat "tongue and cheek" fashion. I have been to the factory to pick up new aircraft, and I have met Sergei as my unit was one of the first to fly the Fire Hawk and Medevac HH-60s.
I guess I'll beat this dead horse a little more. Not having enough power is an issue of aircraft weight and atmospheric conditions. There are techniques to minimize the power required to land in a mountain LZ, for example, but you either have the required power or you don't. People get into trouble when they attempt a landing with no escape route and they have not predetermined the power required. You must be on the lookout for changing conditions, winds, etc as you continue your approach.
I was stationed at the High Altitude school in Colorado where we teach a very proven and sound procedure for mountain flying.
I guess I'll beat this dead horse a little more. Not having enough power is an issue of aircraft weight and atmospheric conditions. There are techniques to minimize the power required to land in a mountain LZ, for example, but you either have the required power or you don't. People get into trouble when they attempt a landing with no escape route and they have not predetermined the power required. You must be on the lookout for changing conditions, winds, etc as you continue your approach.
I was stationed at the High Altitude school in Colorado where we teach a very proven and sound procedure for mountain flying.
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And that procedure is get someone else to fly it and retire to a safe distance - I belive it is known as "the pub"
Regardless - fly safe y'all. Plan the trip, brief the trip, fly the plan and debrief the flight.
Regardless - fly safe y'all. Plan the trip, brief the trip, fly the plan and debrief the flight.
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HeliChopper JoyRides
Official USN Mishap Report issued {excerpts}:
{San Diego Union-Tribune/U.S.}
Two U.S. Navy instructor pilots from San Diego have been forever stripped of flying status and two student pilots will have to repeat training because of a September 2010 incident in which they dipped two $33 million helicopters into Lake Tahoe while trying to take photos for the squadron’s Face-Book page, a Navy official said Wednesday.
.... Both aircraft went into the water, though the amateur video footage only captured one, Navy officials have said. Repairs totaled $505,000.
The Navy’s report on the incident, released Wednesday, holds harsh words for the two flight instructors, both lieutenants, at the controls that day...
“Their complacency, lack of flight discipline and succession of poor judgments nearly led to the loss of two aircraft and 10 U.S. Navy sailors for no benefit and did result in the damage of two aircraft.” ...
The commanding officer at the time, who was not named, created a climate that contributed to the mishap, it concluded.
The year before, the commander himself flew over Lake Tahoe at a low altitude, about 200 feet from the water — something that had “no valid training or operational reason.” The report also criticized the commander for laissez-faire oversight of flights headed outside of San Diego. ...
The two Navy helicopters were returning from participating in the California Capital Airshow at the former Mather Air Force Base. The report said one of the flight instructors organized the trip because the airshow was close to family members in Sacramento.
They decided to hover over Tahoe’s Emerald Bay so they could get a nearby island in the background of the shot, which they planned to offer for the squadron’s Face-Book page.
.... Both aircraft went into the water, though the amateur video footage only captured one, Navy officials have said. Repairs totaled $505,000.
The Navy’s report on the incident, released Wednesday, holds harsh words for the two flight instructors, both lieutenants, at the controls that day...
“Their complacency, lack of flight discipline and succession of poor judgments nearly led to the loss of two aircraft and 10 U.S. Navy sailors for no benefit and did result in the damage of two aircraft.” ...
The commanding officer at the time, who was not named, created a climate that contributed to the mishap, it concluded.
The year before, the commander himself flew over Lake Tahoe at a low altitude, about 200 feet from the water — something that had “no valid training or operational reason.” The report also criticized the commander for laissez-faire oversight of flights headed outside of San Diego. ...
The two Navy helicopters were returning from participating in the California Capital Airshow at the former Mather Air Force Base. The report said one of the flight instructors organized the trip because the airshow was close to family members in Sacramento.
They decided to hover over Tahoe’s Emerald Bay so they could get a nearby island in the background of the shot, which they planned to offer for the squadron’s Face-Book page.
{San Diego Union-Tribune/U.S.}
Last edited by DelaneyT; 24th Dec 2010 at 12:55. Reason: spell
Below the Glidepath - not correcting
Thread Starter
People get into trouble when they attempt a landing with no escape route and they have not predetermined the power required
