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I wonder if the report of a 4 g push over is accurate. The single poster ABusDrivr also said that the nose pitched up 10 degrees with the power increase but the NTSB said the pitch up was about 4 degrees in its March 12, 2019 update.
Under NTSB CVR protocols only a few people will ever hear the CVR recording. Has someone been authorized to release a gist of the contents through Atlas or the Teamsters? From the NTSB CVR Handbook cited previously, here is the non-disclosure agreement: Cockpit Voice Recorder Handbook for Aviation Accident Investigation, February 2016 CVR NONDISCLOSURE AGREEMENT ACCIDENT ID:_________________________________ Each of the undersigned acknowledges that he/she has read National Transportation Safety Board (NTSB) regulations in Title 49 Code of Federal Regulations 831.11 and 831.13, which are printed on the reverse side of this document, and agrees to comply with those rules. Each undersigned further agrees not to disclose or cause to be disclosed any information from the cockpit voice recorder (CVR) recording or any transcript thereof except as expressly authorized by the NTSB. Approval from the NTSB Investigator-In-Charge must be obtained before disclosure of any information. Disclosure of information to his/her respective organization shall include only that information which is directly related to safety and at no time shall non-pertinent remarks, comments, or conversations be disclosed to any person, party, or organization. By placing his/her signature hereon, the undersigned acknowledges that the unauthorized release of CVR information shall be grounds for immediate dismissal from the investigation, and may result in further legal sanction. I HAVE READ AND UNDERSTAND THE ABOVE CONDITIONS. SIGNATURE NAME (PRINTED) PARTY DATE ____________________ ________________________ ______________ _________ 8.3. CVR disclosure policy does not prohibit a party from implementing safety-of-flight related changes within its organization as a result of its participation in a CVR group, however, the NTSB requires approval by the IIC and the directors of the Offices of Research and Engineering and Aviation Safety of the subject matter prior to any disclosure of CVR information to the group member’s organization. It is the CVR group member’s responsibility to notify the CVR group chairman prior to disclosure. Disclosure of information to a group member’s respective organization shall include only information that is directly related to safety. At no time shall CVR remarks, comments, or conversations be disclosed to any person, party, or organization. It could literally be months before the CVR transcript is released. Did ABusDrivr give us a hot tip on what to expect? Or, did he drop off the Beale Ciphers and depart, never to be heard from again? |
Originally Posted by Murexway
(Post 10425913)
Just got the same sequence of events from an old classmate. Only thing additional was that the FO apparently entered the weather and turbulence with the speed brakes fully deployed. I also got the extra stuff about the FO.
Only additional stuff I saw was that the airplane crashed with the autothrottles and A/P engaged and the elevators were split due to cross inputs on the control columns. It was only 18 seconds from... |
Originally Posted by Old Boeing Driver
(Post 10427859)
1 post and gone?
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Originally Posted by MartinAOA
(Post 10427895)
Don't these comments by Murexway somehow validate ABusDrivr's post?
Originally Posted by Murexway
(Post 10425913)
I also got the extra stuff about the FO.
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Originally Posted by Airbubba
(Post 10427846)
I wonder if the report of a 4 g push over is accurate. ?
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This is in danger of becoming apochryphal. Can anyone point to a verifiable reference to this supposed 4g pushover?
If not, I suggest we move on ... |
This accident happened on feb 23. Almost 30 days ago, so a preliminary report is almost due. Should contain info about a 4g negative dive (with or without a mig 28) |
4g or 49 ?
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Originally Posted by DaveReidUK
(Post 10428149)
This is in danger of becoming apochryphal. Can anyone point to a verifiable reference to this supposed 4g pushover?
If not, I suggest we move on ... There are three families looking for answers. There is media feeding from posted comments. |
Originally Posted by Dave Therhino
(Post 10428105)
A "4g pushover" (-4g, or even -3g) is well beyond the design envelope. They were in a 4g pull up for the last several seconds - maybe that's what you read?
Originally Posted by ABusDrivr
(Post 10425322)
They hit a negative 4 G dive initialy on the FOs push. All you hear is stuff hitting the ceiling and at one point a loud thud. They think the thud may have been the JS hitting the ceiling and maybe not wearing the shoulder harness.
Originally Posted by DJ77
(Post 10428165)
4g or 49 ?
Originally Posted by ABusDrivr
(Post 10427941)
I have tried to respond a few times but for some unknown reason my responses are not being posted. The sequence of events I posted came from a non-Atlas pilot only forum from a US airline. I'm guessing, as well as one other poster here, someone has gotten a rough sequence of events from what happened from someone "in the know."
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Regarding this GA button issue. From what I have read here, the button is only armed when flaps are not "0"
I assume that selection of flaps 1 causes the LED's to extend. If that is so, surely they would have been blown off the airplane by the time it reached 425 knots going down. However the NTSB said they found a very small debris field and there has neen no mention of parts and pieces being found elsewhere. |
A -49 degree pushover B -4g degree pushover C -4g pushover Im going with option A and calling it a typo. The -49 degrees has been established by the NTSB. A minus 4G has not. |
The aircraft would not have survived a -4G push. -1G is the normal airliner design goal for no damage and -1.5 for failure. In addition it’s doubtful to impossible that the airfoil on the 767 would be capable of producing -4 G’s at 210 knots. It’s not a symmetrical aerobatic airfoil and it CL would be very poor under negative G. It would exceed the stalling AOA well before 4 G’s. |
Originally Posted by Sailvi767
(Post 10428736)
The aircraft would not have survived a -4G push. -1G is the normal airliner design goal for no damage and -1.5 for failure. In addition it’s doubtful to impossible that the airfoil on the 767 would be capable of producing -4 G’s at 210 knots. It’s not a symmetrical aerobatic airfoil and it CL would be very poor under negative G. It would exceed the stalling AOA well before 4 G’s. If there is physical damage to the aircraft in this scenario, would there be bits and pieces departing from it, and which ones? |
Originally Posted by Euclideanplane
(Post 10428745)
Exceeding stalling AoA is incompatible with the video which does show a nose dive and not a stall, is there agreement about that?
If there is physical damage to the aircraft in this scenario, would there be bits and pieces departing from it, and which ones? So we can pretty safely rule out -4g on aerodynamic/physics reasons alone. |
Originally Posted by Euclideanplane
(Post 10428745)
Exceeding stalling AoA is incompatible with the video which does show a nose dive and not a stall, is there agreement about that?
If there is physical damage to the aircraft in this scenario, would there be bits and pieces departing from it, and which ones? |
Aerobatic performances do not reach that amount of negative G-force nor does a fighter plane. At -4G with a transport category aircraft the structure will fail. This is NOT a legitimate 767 Vg diagram but borrowed from another thread on here for the purposes of explaining. https://cimg2.ibsrv.net/gimg/pprune....6cb2d4050.jpeg You can’t just pull or push unlimited. You need to stay within the operating envelope both in positive and negative G. Again this is NOT a 767 diagram so ignore the speeds it’s about the aerodynamic principles. The “normal” stall speed is the speed at which the aircraft stalls under unaccelerated flight at 1G. Above this speed we call it an “accelerated stall” as we our now stalling the aircraft at a higher speed and higher then 1G. The limit for this is Va or maneuvering speed. Above this speed we will overstress the airplane before it stalls. Could be temporary or permanent deformations of structure depending on the speed. This requires inspections and possibly repairs. We have something similar below the 1-G line although the area in the graph is much smaller. Keep in mind that we float (weightless) at 0G and even -1G is a pretty radical maneuver let alone -2G. Design and certification criteria mandate the aircraft is much stronger on the “+” side then on the “-“ side of the graph. Just as an example, hard landings are “-” and even extreme turbulence may not go much past -1G if at all unless we fly into a massive thunderstorm. Keep in mind again, 0 is weightless and -1 we’re being accelerated out of our seats. Here is a rare example of extreme turbulence that sent a galley cart into the ceiling. That will already happen at -.01G during which it will float up and at -0.3 it will probably smack the ceiling. https://cimg5.ibsrv.net/gimg/pprune....eb9d53c67.jpeg With all respect but I think the ones that advocate the -4G theory have never experienced even -1G. Have a look at the diagram again. In short the airplane would have come apart at -4G or at the very least lost the tail. It did not, the videos show it with all major components attached. |
Originally Posted by B2N2
(Post 10429073)
Aerobatic performances do not reach that amount of negative G-force nor does a fighter plane. At -4G with a transport category aircraft the structure will fail. This is NOT a legitimate 767 Vg diagram but borrowed from another thread on here for the purposes of explaining. https://cimg2.ibsrv.net/gimg/pprune....6cb2d4050.jpeg You can’t just pull or push unlimited. You need to stay within the operating envelope both in positive and negative G. Again this is NOT a 767 diagram so ignore the speeds it’s about the aerodynamic principles. The “normal” stall speed is the speed at which the aircraft stalls under unaccelerated flight at 1G. Above this speed we call it an “accelerated stall” as we our now stalling the aircraft at a higher speed and higher then 1G. The limit for this is Va or maneuvering speed. Above this speed we will overstress the airplane before it stalls. Could be temporary or permanent deformations of structure depending on the speed. This requires inspections and possibly repairs. We have something similar below the 1-G line although the area in the graph is much smaller. Keep in mind that we float (weightless) at 0G and even -1G is a pretty radical maneuver let alone -2G. Design and certification criteria mandate the aircraft is much stronger on the “+” side then on the “-“ side of the graph. Just as an example, hard landings are “+” and even extreme turbulence may not go much past -1G if at all unless we fly into a massive thunderstorm. Keep in mind again, 0 is weightless and -1 we’re being accelerated out of our seats. Here is a rare example of extreme turbulence that sent a galley cart into the ceiling. That will already happen at -.01G during which it will float up and at -0.3 it will probably smack the ceiling. https://cimg5.ibsrv.net/gimg/pprune....eb9d53c67.jpeg With all respect but I think the ones that advocate the -4G theory have never experienced even -1G. Have a look at the diagram again. In short the airplane would have come apart at -4G or at the very least lost the tail. It did not, the videos show it with all major components attached. |
Pitch -49 must have been misquoted somewhere as Pitch -4g which then took a life of its own. Its not possible. Hard landings are actually “-“ as far as the structure is concerned. Previous post corrected. |
-4G’s in this accident is a myth |
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