This could mean trouble for someone

Discussion in 'Academy/Military News' started by AF6872, Sep 25, 2010.

  1. AF6872

    AF6872 Member

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  2. Mongo

    Mongo Banned

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    The evolution itself is not a big deal. Practicing and training for over water SAR is the responsibility of each and every Navy helicopter aircrew with maybe the exception of the MH-53 guys. Procedures are to approach the victim, drop to 5’ altitude and jump the swimmer, and then resend to a 40’ hover and hoist the swimmer and victim aboard. Fresh water is much more preferable than sea water due to the absence of corrosion. A post-flight wash job is not necessary. A good crew will never pass up a deserted fresh water lake in order to practice. They will not get in trouble for this.

    Now, the down side. Navy pilots don’t hover above sea level. Lake Tahoe is over a mile high in elevation. There is a lot less lift in the air. And these guys are not proficient at flying in it. Not seeing the initial part of the approach, I can only surmise, but apparently the helo entered a phenomena called settling with power. This is a state in a steep slow descent where a vortex sets up in the end of the rotor blades and they actually recirculate the same air. Consequently, much less lift available. The recovery is to actually reduce pwer, push the nose over, dive for the deck, and fly it out. Completely contrary to what one wants to do which is to add more power. This will only worsen the effects. My guess is that he added power to the point that the tail rotor lost directional control, hence the rotation to the right, and the aircraft continued to settle into the water. Supporting my theory is the fact that once the vortex dissipated, the aircraft had plenty of power to fly out of the water on its own (and it takes quite a bit more power to break free from the water than it does to hover.)
     
  3. Luigi59

    Luigi59 Banned

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    If this kind of stunt is normal, then why were they suspended/grounded by the Navy?

    "..both pilots have been grounded until the investigation is complete and they could face administrative action — and even lose their flying qualifications — depending on the outcome."​

    If this is normal, why is there even an investigation?

    Sounds/looks more like a joyride that went wrong, and they got caught.
     
  4. Luigi59

    Luigi59 Banned

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    As suspected:

    "US Navy officials from the Pentagon told NBC News this was not a training mission,
    but that the two helicopter crews were allegedly attempting to take photos of each
    other’s helicopters hovering just above the waters of Lake Tahoe with the mountains
    as a majestic backdrop when their photo op went horribly wrong."​
     
  5. AF6872

    AF6872 Member

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    I did see something about the lift factor at 6,000ft as compared to sea level which may have caused the problem. I remember my first day at Tahoe. Walked down a trail from the picnic area to the Lake on the east side. Nice down but the way back up coming from sea level on that morning was a real challenge. Think he RED-LINED???
     
  6. Mongo

    Mongo Banned

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    Yes, but because of the inefficiency of the rotors due to the settling with power issue. Once he was in the water and the vortex dissapated, he had plenty of power.

    The issues will be should he have recognized that he was too slow and too steep and in danger of entering a settling with power condition? Once in the condition, did he have enough altitude available to fly it out by lowering the nose and decreasing power? If by some slim chance, the answer to the first question was 'no' and the by examing the video, it is determined that the second answer is also 'no', and the only remaining alternative was to land in the water, perhaps he will be totally exhonerated. It was a good landing and takeoff.
     
  7. flieger83

    flieger83 Super Moderator Moderator

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    Mongo, did I miss something all this time? :scratch:
    (you MUST be a rotor head) :smile:

    I say this because your description of "settling with power" is text-book perfect! I have a very close friend who is a CFI-H and he was explaining an accident in Utah a couple of years ago, there was video, and he was like a school professor explaining the effect of elevation, density altitude, etc., on a helo and how to get out (dive, obtain if I remember correctly translational lift?) and then fly away.

    Nicely stated!!! :thumb:

    Steve
    USAFA ALO
    USAFA '8
     
  8. scoutpilot

    scoutpilot Member

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    Settling with power is a likely culprit, as Mongo identified. Of course, the natural reaction of increasing power only makes it worse. No room to dump power and fly out of it.

    Before I give much credence to the 6000' PA difference at Lake Tahoe, I'd want to see the weight & balance. With less than a full load if fuel and short of a heavy-*** cargo load, the -60 has an enviable power margin.

    Mongo, I haven't hovered IGE over water, but I'd assume that pull all that spray through the rotor can't help your lift as it effectively modifies the relative DA. Is that the case, in your experience?

    You know what they say...one "oh ****" wipes out all the "attaboys"!
     
    Last edited: Sep 25, 2010
  9. Mongo

    Mongo Banned

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    I don't think they were violating either FAA or Navy-wide regs being there. Tahoe is an established seaplane location.
     
  10. scoutpilot

    scoutpilot Member

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    Yes, the textbook solution is to reduce power and arrest the rate of descent with translational lift, achieved with directional airspeed, which is almost always forward. Of course the real world solution can be much harder, since the conditions that play into settling with power factor (20-100% of available power applied, low airspeed, and rate of descent >300 fpm) usually are manifested in situations where terrain is a factor, e.g. during a steep approach to a hover or landing. When you're 100 feet off the deck and you start settling, it's likely that you'll smack the earth. You're going to lose altitude before you realize the condition, and then when you nose over to get out of it you've put the aircraft in a dive attitude with a rate of descent with maybe 50-75 feet left before a significant emotional event occurs.

    In general, the Army has found that the more powerful the aircraft, the more likely a settling event will occur.
     
  11. kp2001

    kp2001 USMMA Alumnus

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    It is apparently being investigated as a Class C Mishap.

    Depending on the findings (or possible concurrently) there will be a FNAEB (Field Naval Aviator Evaluation Board) which would then determine the disposition of the pilots.

    I won't even pretend to know all the circumstances of this event, that's what the mishap board is for. I'm just glad I'm not on the board, although a free trip to Tahoe might have been nice.
     
  12. kpforson

    kpforson Parent

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    LTE maybe... Loss of Tail rotor Effectiveness ...spinning right... low sink rate
     
  13. Mongo

    Mongo Banned

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    Yes, but it is secondary to the real problem. Note that prior to hitting the water that the main rotor blades are severely coned. It has lost it's effectiveness because it is turning at probably about 80% or less.
     
  14. flieger83

    flieger83 Super Moderator Moderator

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    THIS is one of the reasons I really REALLY love my twin throttles and around, oh, 50,000lbs or so of raw thrust in zone 5! :worship:

    :worship: Burner :worship: to the wall baby and power out of it!!! :thumb:

    Steve
    USAFA ALO
    USAFA '83
     
  15. raimius

    raimius USAFA Alumnus

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    Flieger, I just got the image of the Emperor from Star Wars yelling "Power! Unlimited Power!"...crossed with an F-15 going vertical.

    :yllol:
     
  16. flieger83

    flieger83 Super Moderator Moderator

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    Until you've taken an Eagle vertical...you just DO NOT know....:thumb:

    Steve
    USAFA ALO
    USAFA '83
     
  17. Mongo

    Mongo Banned

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    That's why jets are for kids. They're easy to fly.
     
  18. Bullet

    Bullet Member

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    So easy, even a WSO can do it! :biggrin:

    Steve post reminds me a my all-time favorite radio call during my career:

    Diverted to Eielson for an IFE. RTB sortie to Elmendorf the next day (Saturday, so just a quick cross-country home planned), Conformal tanks locked out (no gas = 9K # lighter), 229 engines (the big thrustee - kind for Eagles), cold Alaska day (easier to climb in). Requesting unrestricted climb on departure, got the OK (Saturday morning, no traffic out of Fairbanks, so easily approved)

    400 Kts by 7000', keeping it low to the deck, and PULLLLLLL to the vertical....

    Look through the tails, and Eielson departure end is STILL under neath us as we are rocketing straight up.

    Our radio call (climbing through 10,000 feet): "Alaska Center, Dice 1, Departure from Eielson, request direct Elmendorf"

    Center's reply: "Dice One, good morning, climb and maintain Flight Level 290"

    Pause for a potato, then he comes back up, laughing: "Never mind, you're already there!"

    Yep, and having that much power can be fun as heck!:thumb:
     
  19. majmattmason

    majmattmason Member

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    Funny story!
     
  20. AF6872

    AF6872 Member

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    For those who might be following this it is in any pilots DNA. "F-4 Pilot 'I am three minutes out your site and requesting Bubble Check'. "Dressy Lady to F-4 you are clear" Everyone runs for every available camera. F-4 screams in at about one hundred feet over the mountain, rotates ninety degrees and flys between two radar towers, recovers and goes gate on vertical to about two thousand feet. Asked if he could do it one more time for those who couldn't get the cameras out in time and the answer was "sorry BINGO and RTB". Unathorised pickup on pad by Huey. Command pilot asks "has everyone ridden in a helicoptor before?" New second Lieutenant says "No". Pull the belts real tight. Pilot flys down jungle road at about fifty feet for one hundred yards with nose down about sixty degrees. Pops out of the canopy and begins to rock and roll side to side. Thank heaven for that certain DNA strand. They risk their lives every time the wheels leave the tarmac.
     

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