# Lets open the floor for comments on this about Egyptair flight 990.. **URL:** \ **Category:** Great Debates\ **Created:** [November 16, 1999, 2:35am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964 "1999-11-16T02:35:00Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![Surgoshan](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Surgoshan](https://boards.straightdope.com/u/Surgoshan)\ **Post date:** [November 19, 1999, 7:28am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/41 "1999-11-19T07:28:00Z")
What’s that Tris? Explain the Manhattan bit? I’m talking about that one project alone. Are you talking about the large amounts of nuclear usage elsewhere? ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [November 19, 1999, 7:38am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/42 "1999-11-19T07:38:00Z")
> [@](#): > > I’m talking about that one project alone. Are you talking about the large amounts of nuclear usage elsewhere? Ok, Only the Manhattan Project, you can claim lower numbers, but people were allowed to be exposed to deadly levels of radiation, and the consequences covered up. Later projects in nuclear weapons, and delivery systems not specific to the Manhattan Project were as deadly, including to people in other countries, such as Micronesia, and those too were covered up. The US Government does kill people, and does cover it up. I don’t think that the whole fabric of conspiracy theory is more believable than the word of the Defense Department, or the Energy Department, but I don’t find their assurance to be unassailable, either. Just because there are some really whacked out people who are afraid of the Government, doesn’t mean that the Government doesn’t have its own completely whacked out folks, too. \

Tris\ ---

**Author:** ![Surgoshan](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Surgoshan](https://boards.straightdope.com/u/Surgoshan)\ **Post date:** [November 19, 1999, 3:19pm UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/43 "1999-11-19T15:19:00Z")
Hmm, I think I’ll sell my bonds now. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [November 19, 1999, 8:40pm UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/44 "1999-11-19T20:40:00Z")
E1Skeptic: I know some large airplanes have separate right and left elevators that can be controlled independently by the left and right control yokes, should any physical linkage between the control yokes fail. Is the B767 such an airplane? ---
**Author:** ![E1skeptic](https://avatars.discourse-cdn.com/v4/letter/e/3da27b/32.png) [@E1skeptic](https://boards.straightdope.com/u/E1skeptic)\ **Post date:** [November 20, 1999, 6:21am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/45 "1999-11-20T06:21:00Z")
Tracer: I don’t know if the 767 has such kind of split-controlled elevators. Could be. Unfortunately I don’t have access to any manuals or direct info right now (I’m in Canada, visiting my youngest son :), and using his computer). I will be back home in a few more days, and will be able to give you an answer. Saludos. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [November 20, 1999, 4:38pm UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/46 "1999-11-20T16:38:00Z")
My knowledge about split-elevator controls comes from one (1) paragraph in a book titled _The Turbine Pilot’s Flight Manual_, by Brown & Holt, Iowa State University Press, page 68-69: \“In pitch, redundancy is often accomplished by splitting elevator controls with a clutch, or it is achieved through the use of alternate power sources for the elevators.  Separate lines from each control yoke are again connected via a clutch, which may be overpowered or disconnected in a jamming situation.  On the Dash-8, for example, there’s a manually released clutch between the yokes.  When the controls are separated, each pilot controls only his or her own half of the elevator.  You may have noticed, when taxiing behind a DC-9 or MD-80, that one elevator sometimes droops well below the other.  This is because the elevators aren’t mechanically linked together in movement.  Until there’s enough airspeed for control tab effectiveness, each elevator seeks its own position, based on airflow over the control surfaces.  A stiff breeze can lift the upward elevator on the taxiing aircraft.”\ I’d be interested to know whether the position of EgyptAir 767’s control-yoke clutch is detectable by its flight recorder, and if so, whether it was engaged or disengaged at the time of the elevator split. * * * Quick-N-Dirty Aviation: Trading altitude for airspeed since 1992. ---
**Author:** ![E1skeptic](https://avatars.discourse-cdn.com/v4/letter/e/3da27b/32.png) [@E1skeptic](https://boards.straightdope.com/u/E1skeptic)\ **Post date:** [November 22, 1999, 7:45am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/47 "1999-11-22T07:45:00Z")
Tracer: Yes, the position of the elevators is recordable. I just got home, and will get some more info soon, but in the meantime, why don’t you check this thread in the PPRuNe out? [767 split elevators](http://www.pprune.org/ubb/NonCGI/Forum3/HTML/000473.html) Back later… ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [November 22, 1999, 11:24pm UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/48 "1999-11-22T23:24:00Z")
Hmmm … that thread E1Skeptic just linked to contained the following passage by a DrSyn: > [@](#): > > On the 767, both sides of the stabilizer are mechanically linked as one unit. The elevators and control columns, however, are protected by overides which allow breakout if either a column (and its runs) or an elevator jam. I believe a force of around 50 lbs has to be applied in order to activate the overide. It sounds as though, if the captain were to have PULLED really hard and the first officer were to have PUSHED really hard, this override would be activated and each control yoke would control its half of the elevators independently. It still isn’t clear whether the engagement of that override would be recorded on the flight recorder, even if the positions of the elevators themselves were. * * * Quick-N-Dirty Aviation: Trading altitude for airspeed since 1992. ---
**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\ **Post date:** [November 22, 1999, 11:51pm UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/49 "1999-11-22T23:51:00Z")
This is what I read on Yahoo news today: [FBI Investigating EgyptAir Pilots](http://dailynews.yahoo.com/h/ap/19991122/us/egyptair_investigation.html) > [@](#): > > So far, this picture of the crash has emerged from the voices and data recorded in the cockpit and radar: > > The Boeing 767 rose routinely after takeoff from New York’s Kennedy Airport. It had reached its cruising altitude for the 11-hour flight when the 57-year-old pilot, Ahmed al-Habashi, apparently left the cockpit briefly. > > This appeared to have left the plane in the hands of El-Batouty, 59, the relief co-pilot who shortly before had come into the cockpit announcing he wanted to fly earlier than scheduled. > > After the captain left, El-Batouty apparently made the remark about his fate being in God’s hands. Then the autopilot was disengaged. It was 1:49:46 a.m. > > Eight seconds later, the plane was in a steep dive at near supersonic speed. > > Investigators say the pilot could be heard on the cockpit recorder saying, ``What’s going on?’’ and apparently grabbed the steering yoke to try and bring the plane out of its descent. > > ``Pull with me! Please. Pull with me!’’ investigators quoted him as saying. > > The plea was met with silence from El-Batouty, the recorder showed. Flight data indicates that while the pilot pulled up, the co-pilot apparently pushed down to point the nose toward the ocean. * * * La franchise ne consiste pas à dire tout ce que l’on pense, mais à penser tout ce que l’on dit. H. de Livry ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [November 23, 1999, 12:06am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/50 "1999-11-23T00:06:00Z")
Well… Apparently what was said wasn’t said…so it wasn’t suicide? Aircraft malfunction has been ruled out… Where do they go next? * * * If you can’t convince them, confuse them. Harry S. Truman ---
**Author:** ![E1skeptic](https://avatars.discourse-cdn.com/v4/letter/e/3da27b/32.png) [@E1skeptic](https://boards.straightdope.com/u/E1skeptic)\ **Post date:** [November 23, 1999, 5:43am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/51 "1999-11-23T05:43:00Z")
**Tracer** : most probably the override’s condition is not going to get recorded, and besides, what the DFDR records depends a lot on what’s fitted to the particular aircraft, which itself depends on Country’s regulations, Company policies, etc. FAA’s minimum requirements are listed on this page: [FAA’s DFDR Req’s](http://members.aol.com/mcdpilot/dfdr.html). (courtesy of one of the pilots on the PPRuNe MB). Seems that the 767-300 DFDR’s record about 150 items, but I still doubt it records the condition of the elevator’s override. Probably the best thing would be to retrieve the whole gadget from the ocean floor, and analize it. Let’s wait. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [November 24, 1999, 2:54am UTC](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964/52 "1999-11-24T02:54:00Z")
Arnold quoted Yahoo! News as saying: > [@](#): > > Flight data indicates that while the pilot pulled up, the co-pilot apparently pushed down to point the nose toward the ocean. If they got this from the same NTSB report that E1Skeptic pointed out above, then Yahoo! News is as guilty of jumping to unjustified conclusions as CNN was. The _elevators_ were showing a 7-degree difference in angle. The control yokes _controlling_ those elevators weren’t mentioned in the report. It is entirely possible that one elevator was reporting “up” while the other was reporting “down” because the overspeed condition the plane was experiencing during its dive pushed the two elevators into chaotic angles. As E1Skeptic says, let’s wait and see. It typically takes the NTSB months to analyze an aviation accident before they arrive at a conclusion. Resist the temptation to make up your mind prematurely, no matter how much the news media cater to that desire. * * * Quick-N-Dirty Aviation: Trading altitude for airspeed since 1992. [Previous page](https://boards.straightdope.com/t/lets-open-the-floor-for-comments-on-this-about-egyptair-flight-990/16964.md?page=2)