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Delta 767 emergency landing GSP

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  • Delta 767 emergency landing GSP

    http://www.wyff4.com/news/15645321/detail.html

  • #2
    Leave it to the media to create a dramatic event over almost nothing.
    Signatures are overrated

    Comment


    • #3
      Ruptured Bleed Air Duct

      A ruptured bleed air duct can be quite serious, depending on what the high temp air blows on. I had to investigate an accident where the probable cause was a ruptured bleed air duct. There wasn't enough of the plane remaining to be certain.

      Comment


      • #4
        Definately very dangerous not to mention scary to the passengers.

        Can anyone explain how hot bleed air can make it past the pack, primary/secondary heat exchangers and into the cabin? Aren't the ducts monitored by fire loops to inform crew to close off said bleed valves?

        Comment


        • #5
          Originally posted by T.O.G.A.
          Can anyone explain how hot bleed air can make it past the pack, primary/secondary heat exchangers and into the cabin? Aren't the ducts monitored by fire loops to inform crew to close off said bleed valves?
          The short answer to your question is yes, they are. The longer version is that we don't yet know what precisely happened in this case, whether this was a PACK overtemp or overpress or both or which duct blew and when. I don't fly the 76, but on our airplane the ducts downstream of the PACK are not monitored, the reasoning being that you will get a PACK overpress/overtemp with the PACK automatically kicking off before it will cause you any problems in the downstream ducts.

          We'll have to see what they find here.

          Comment


          • #6
            Originally posted by flyboy2548m
            I don't fly the 76, but on our airplane the ducts downstream of the PACK are not monitored, the reasoning being that you will get a PACK overpress/overtemp with the PACK automatically kicking off before it will cause you any problems in the downstream ducts.
            Right, they are also not monitored also because the air after the mixing valves is not particulary hot. Yet, a passenger was burned. Very peculiar.

            Looking forward to hearing what occurred.

            Comment


            • #7
              Originally posted by T.O.G.A.
              Right, they are also not monitored also because the air after the mixing valves is not particulary hot. Yet, a passenger was burned. Very peculiar.

              Looking forward to hearing what occurred.

              The article was written in an overly dramatic way. I would take little of what was in it for truth. The passenger that clamed to be burned refused treatment for the burn. That makes me think the passenger was not really burned. Here is different article less all the false drama

              Signatures are overrated

              Comment


              • #8
                Twa 800

                I forget the exact details of the pack and the fuel tank on TWA 800, I know the official explanation was a chafed wire bundle not the pack, but is it possible for a pack with a broken duct like on the Delta flight to get hot enough to start a real fire ?
                ASMEL-IA 1978 A&P-IA 1965 First Aloft 1954 DC-4
                Dad: B-24 Ploesti Self: U205A1 private ops Nam

                Comment


                • #9
                  agreed. a much better article.

                  Comment


                  • #10
                    Originally posted by Uncle Jay
                    I forget the exact details of the pack and the fuel tank on TWA 800, I know the official explanation was a chafed wire bundle not the pack, but is it possible for a pack with a broken duct like on the Delta flight to get hot enough to start a real fire ?
                    The temperature of the bleed air in the ducts coming from the engines is between 100 and 250 degrees C (about 200 to 480 F). It's hot enough to to get paper to burn, plastic will melt and smoke. The air is also under pressure, between 15 and 55 PSI depending on the engines power setting. The high numbers approximate take off thrust. The low numbers are idle.

                    At higher power settings the temperature and pressure can damage light aluminum secondary structures and composite fiberglass panels. Given a long enough exposure at high power settings, bleed air can damage primary structure.

                    I've seen 3 duct failures, all on the 747-100 pre AD. Two were in the wing, one was in the aft end of the forward belly. All caused some secondary damage to the surrounding area, none caused the pilots any concern once the appropriate check list was accomplished.

                    The AD changed the way the ducts were stress relieved after fabrication and before pressure testing.
                    Don
                    Standard practice for managers around the world:
                    Ready - Fire - Aim! DAMN! Missed again!

                    Comment


                    • #11
                      Bleed air come from the high pressure stage of the engine. That air gets VERY hot as per the pic.

                      Signatures are overrated

                      Comment


                      • #12
                        Video of passenger's account

                        This is a passenger account of what happened. Sounds like the fa didn't help matters by saying fire.
                        Click on enlarge video if it doesn't play the first time.

                        Comment


                        • #13
                          Originally posted by Airfoilsguy
                          Bleed air come from the high pressure stage of the engine. That air gets VERY hot as per the pic.
                          Bleed air comes from two different engine bleed ports depending on the needs of the aircraft. When the engine is operating at low power, the bleed port on the high pressure compressor is used. The pressure required by the aircraft is more than can be delivered by the low compressor bleed. At cruise or higher powers bleed air is supplied by the low compressor bleed. In the pylon, a heat exchanger cools the air before it enters the wing ducting. A part of the valve isolating the engine from the aircraft has a flow and temperature limiting feature that closes the valve if either flow or temperature is exceeded.

                          The engine bleed ports are normally identified be the stage of compression where the bleed is located. Generally the bleeds are located at the last stage of compression for each compressor spool. On the old JT3D (707 / DC8 engine) the bleeds were 9th and 16th. Each engine type may bleed air from a different port. The important thing is one bleed is from the low compressor spool and the other is from the high spool.
                          Don
                          Standard practice for managers around the world:
                          Ready - Fire - Aim! DAMN! Missed again!

                          Comment


                          • #14
                            Originally posted by Dmmoore
                            On the old JT3D (707 / DC8 engine) the bleeds were 9th and 16th.
                            On the CF34 it's 7th, 10th and 14th.

                            Comment


                            • #15
                              Typical but not appropriate

                              Originally posted by Airfoilsguy
                              Leave it to the media to create a dramatic event over almost nothing.
                              This is the "typical" response from those of us who know a lot about aviation and are quick to blame the media and/or the passengers for overreacting.

                              But if you think this particular incident is "almost nothing", I would strongly disagree.

                              This was a dangerous event and I would not want to have been a passenger on that flight.

                              Although, I must admit ... this is a bit ridiculous:

                              We're sitting four and five people in two seats.

                              Comment

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