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  • "Unusual dual engine failure" says report

    April Crash Of F-18 attributed To Rare Dual Engine Failure


    CNN) -- A Navy F-18 fighter jet that crashed into a Virginia Beach neighborhood in April experienced dual engine failure, marking the first time an F-18 has had two unrelated catastrophic engine failures at the same time, according to a report released on the investigation.


    In the first five seconds of flight, the jet's right engine stalled from a fuel leak, the investigators said. The pilot tried to compensate with extra thrust from the left engine but it also failed due to an unrelated problem with the afterburner.

    "It was not a single failure but an extremely unusual and complex multisystem emergency," Rear Adm. Ted Branch said at a press conference Monday.



    With a failed right engine and a malfunctioning left engine that was not generating sufficient thrust, the aircraft quickly lost altitude. When the F-18 dropped to 50 feet the crew ejected.

    One second later the jet crashed into an apartment complex, but no one was killed.

    The whole ordeal, from takeoff to crash, lasted only 70 seconds.



    If the right engine alone had failed, it is highly unlikely the aircraft would have crashed, Branch said.

    "We have never had this kind of unrelated dual engine mishap in the F-18," he said. "It's the first time its ever happened with this aircraft."

    Emergency procedures will be revised to take this rare occurrence into account, he said.

  • #2
    Re: "Unusual dual engine failure" says report

    I wonder what the descent rate/glide ratio... is of an F18 without power?

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    • #3
      Re: "Unusual dual engine failure" says report

      I found this info for the F-18 (not sure which variant):


      Best Glide is 245 KIAS. (That's based on a 16,000lb gross weight)

      With zero wind & a straight line glide (no tips or external stores, gear up & T/O flaps - 245 Knots will give you 9NM at 10,000ft of Altitude.



      At THAT speed you could probably get a brick to fly...

      Anyway, back to glide ratios... 9nm = 54,685.17 feet. 54,685 /10,000 = 5.46 glide ratio (I think....corrections?)



      These pilots had no open area large enough and nearby enough to dive, build up speed and then land it anyway. At 200+ knots landing speed you'd need a LOT of straight, open pavement at touchdown, and with the shuttle-like dive angle you'd need to maintain that speed would require more altitude than they had to work with.

      These pilots had to try and fly their craft as long as possible in hope of clearing neighborhoods and bring it down in an uninhibited area. The fact that they waited until 50-feet off the ground tells me that very clearly. Good form guys!
      Last edited by AirDOGGe; 07-06-2012, 06:59 PM.

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      • #4
        Re: "Unusual dual engine failure" says report

        Thanks for the figures on the F18. How about a comparison between a Cessna 182, Lear Jet, a 747, Rare Bear or Strega or a Stock Mustang or Stock Bear Cat all without power, so we have some idea of the variations.

        Would the glide ratio be 5.4' forward for every 1' descent at 245kph? 9 miles at 10,000 feet. That's almost a mile for every 1,000 altitude. Seems like it would be a lot worse than those figures?
        Last edited by SkyvanDelta; 07-06-2012, 07:20 PM.

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        • #5
          Re: "Unusual dual engine failure" says report

          [QUOTE=AirDOGGe;102842]I found this info for the F-18 (not sure which variant):

          Anyway, back to glide ratios... 9nm = 54,685.17 feet. 54,685 /10,000 = 5.46 glide ratio (I think....corrections?)QUOTE]

          Nope, looks like your seeing the same I found too, It is a home sick anvil.

          Best Glide is 245 KIAS. Which above 50,000ft is actually supersonic! he he.
          Thats based on a 16,000lb gross weight, you add 5 KIAS per extra 1,000lbs over 16,000lbs.

          With T/O flaps & Tips your approach speed is 225KIAS & touchdown is 196KIAS.. That'll make a Viper driver's eyes water! Laughing
          If you used LAND flaps those speeds change to 215KIAS for approach & 188KIAS for Touchdown.

          With Zero Wind & a straight line glide, No Tips or External Stores, Gear Up & T/O Flaps. 245 Knots will give you 9NM at 10,000ft of Altitude.

          20,000ft gets you 18NM
          30,000ft gets you 28NM
          40,000ft gets you 38NM
          50,000ft gets you approximately 48NM.

          You can achieve the same Glide Ratio without T/O Flaps by increasing your Best Glide Speed to 275KIAS

          The glide distance decreases by 5 1/2NM per 10,000ft with the gear down!

          I remember reading somewhere that generally, supersonic fighters have somewhere between 5 to 1, and 8 to 1 (coefficient of lift to coefficient of drag = glide ratio) while optimized for dead stick.

          Although, in the Hornets defense, I also seem to recall reading that F-4 Phantoms were kings of homesick angels at around 4 to 1.
          Hey! maybe "Bear Driver" can chime in!!!

          And, I for one am positive that if we asked Darryl Greenameyer about the glide characteristics of his F-104RB (Red Baron), even just the expression on his face all by itself would speak volumes!!!
          Carbon is groovy man...

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          • #6
            Re: "Unusual dual engine failure" says report

            Originally posted by SkyvanDelta View Post

            Would the glide ratio be 5.4' forward for every 1' descent at 245kph?
            Roger that. I should have said "5.46 to 1" glide ratio. Five and a half feet forward for every foot lost in altitude.



            Originally posted by SkyvanDelta View Post
            9 miles at 10,000 feet. That's almost a mile for every 1,000 altitude. Seems like it would be a lot worse than those figures?

            Well, lets not forget that at that best glide velocity they are covering over 400 feet every second, or a mile every 13 seconds! They cover that 9nm distance in less than 2 minutes.




            Originally posted by C_roundy View Post

            Although, in the Hornets defense, I also seem to recall reading that F-4 Phantoms were kings of homesick angels at around 4 to 1.


            Perhaps for in-service aircraft, but at a ratio of 1.5 to 1, here lie the true kings worthy of the title of "Flying Bricks":









            By the way, if you enjoy reading aviation books on aircraft as I do, click on that book cover image and your browser will take you to it.

            NASA has made a number of such books available for free on the 'net, including this fascinating release. Said image link will take you to an online version of the complete print, including photos.

            If you ever wanted to know practically everything there is about these "Six Million Dollar Man" wingless marvels, then this link is for you.



            (Click on the CONTENTS link in the lower left of the page to open the book after the title page opens.)




            Enjoy!


            .
            Last edited by AirDOGGe; 07-06-2012, 09:31 PM.

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            • #7
              Re: "Unusual dual engine failure" says report

              Some glide ratios

              Skydiving Wingsuit 2.5 to 1


              Cessna 172 = 9 to 1

              747 clean = 17 to 1
              Latest news coverage, email, free stock quotes, live scores and video are just the beginning. Discover more every day at Yahoo!



              Md-80 Twin Engine Short to Medium Range Commercial Airliner, clean = 28 to 1


              P51 Mustang = 15 to 1 at 175mph


              Space Shuttle = 1 to 1
              Latest news coverage, email, free stock quotes, live scores and video are just the beginning. Discover more every day at Yahoo!


              Standard Glider = 40 to 1


              F104 = 5 to 1 clean and 3 to 1 with flaps and gear down


              Some useful information on the F104


              The fuel system is designed so that the pilot must do little else but make sure it is full to start with, and that it is not empty before landing. Normal VFR reserve for this airplane is 1,000 lbs. of fuel. Starting with full internal and full tip fuel, the aircraft will go about 750 nautical miles. If you stay in burner and go fast, you are out of gas in less than 30 minutes

              Maximum Climb 450 knots, 38 degrees, 35,000/min
              Last edited by SkyvanDelta; 07-06-2012, 11:31 PM.

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