# I pit the NTSB's conclusion regarding Flight 587

**URL:** <https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478>\
**Category:** The BBQ Pit\
**Created:** [October 27, 2004, 5:00pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478 "2004-10-27T17:00:25Z")\
**Posts on this page:** 20\
**Page:** 2

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**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\
**Post date:** [October 27, 2004, 7:24pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/21 "2004-10-27T19:24:38Z")

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During a Safety Board investigation, they review all training, checkride and peer evaluations of crew members. That would lead to this statement:

> [@](#):
>
> The first officer had a tendency to overreact to wake turbulence by taking unnecessary actions, including making excessive control inputs.

They also include observations similar to those posted above regarding changes to the aircraft, and training procedures:

> [@](#):
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> The American Airlines Advanced Aircraft Maneuvering Program ground school training encouraged pilots to use rudder to assist with roll control during recovery from upsets, including wake turbulence.

> [@](#):
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> The American Airlines Advanced Aircraft Maneuvering Program excessive bank angle simulator exercise could have caused the first officer to have an unrealistic and exaggerated view of the effects of wake turbulence, erroneously associate wake turbulence encounters with the need for aggressive roll upset recovery techniques, and develop control strategies that would produce a much different, and potentially surprising and confusing, response if performed during flight.

> [@](#):
>
> Before the flight 587 accident, pilots were not being adequately trained on what effect rudder pedal inputs have on the A300-600 at high airspeeds and how the airplane’s rudder travel limiter system operates.

> [@](#):
>
> Because of its high sensitivity (that is, light pedal forces and small pedal displacements), the A300-600 rudder control system is susceptible to potentially hazardous rudder pedal inputs at higher airspeeds.

The worst part about this is that the Safety Board is a toothless watchdog. After every incident, they issue recommendations to appropriate authorities such as the FAA, NHTSA, AAR and others, but they are not empowered to \*require \*corrective action. If the entity holding the power to effect correction does nothing, all the Safety Board can do is cite their previous findings after the next accident.

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**Author:** ![Brutus](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@Brutus](https://boards.straightdope.com/u/Brutus)\
**Post date:** [October 27, 2004, 7:30pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/22 "2004-10-27T19:30:31Z")

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> [@World Eater](#):
>
> Nice, now only if they’ll fedex my wishing machine before the election. 😛

I don’t know what you are worried about, since you can get detailed plans on making a [Philosophers Stone](http://www.futurehorizons.net/strange.htm) for only 99 US-of-A greenbacks!

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**Author:** ![blowero](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@blowero](https://boards.straightdope.com/u/blowero)\
**Post date:** [October 27, 2004, 7:57pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/23 "2004-10-27T19:57:36Z")

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> [@Brutus](#):
>
> Fine, so I didn’t read that bit. But goddamn, that use of normal control surfaces can result in the loss of precious bits is disconcerting. I know that you can do stuff that results in the loss of lift or turns you into a lawn dart or whatever, but what next, pull back on the fly-by-wire control column hard enough and rip off the wings? Sheesh.

But is it even _possible_ to design a plane that’s completely idiot-proof? If I were in the pilot’s chair, knowing nothing about flying, and started randomly pressing buttons, I would pretty much _expect_ the plane to crash. I certainly wouldn’t expect the control mechanisms to “know” that I wasn’t supposed to be doing what I’m doing, and automatically ignore every incorrect input. They could build airplanes like tanks, so it’s impossible for them to break apart, but they wouldn’t be much use if they couldn’t get off the ground.

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**Author:** ![Brutus](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@Brutus](https://boards.straightdope.com/u/Brutus)\
**Post date:** [October 27, 2004, 8:23pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/24 "2004-10-27T20:23:59Z")

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> [@blowero](#):
>
> But is it even _possible_ to design a plane that’s completely idiot-proof? If I were in the pilot’s chair, knowing nothing about flying, and started randomly pressing buttons, I would pretty much _expect_ the plane to crash. I certainly wouldn’t expect the control mechanisms to “know” that I wasn’t supposed to be doing what I’m doing, and automatically ignore every incorrect input. They could build airplanes like tanks, so it’s impossible for them to break apart, but they wouldn’t be much use if they couldn’t get off the ground.

And I would certainly expect the plane to crash if the pilot were getting jiggy with the controls at the wrong time. I hardly expect the onboard computers to prevent unsafe manuevers (though some do prevent/limit some manuevers, from my understanding, like limiting angle of attack). But I do expect the plane to not start falling apart at (relatively) low-speed from the use of control surfaces. I am not a pilot (though I pretend via flight sims), but I am not aware of modern aircraft that lose their ass when you kick the rudder. (well, I know of one now)

It would be like getting in your car, accelerating to 55mph, and cutting the wheel hard left. Sure, you very well may flip over. That is not unexpected behavior for a car going at that speed trying that manuever. But you wouldn’t expect the wheels to rip off from the axle-thingees, would you? Sure, it may not make a practical difference, since you’re about just as fucked, but stilll…

Not to make it sound like I am trying to pin it all on Airbus or something; It does look like there is blame to spread around.

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**Author:** ![MEBuckner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mebuckner/32/2896_2.png) [@MEBuckner](https://boards.straightdope.com/u/MEBuckner)\
**Post date:** [October 27, 2004, 8:26pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/25 "2004-10-27T20:26:33Z")

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> [@The Chao Goes Mu](#):
>
> After the horseshit the NTSB cranked out after TWA flight 800 and the fiasco after the crash in Chicago in 1983 (I forget the flight number.) I am a little skeptical of of their “findings.”

Yeah, because the armchair speculations of assorted tinfoil-hat-wearing conspiracy theorists is clearly more valid than the findings of people with vast collective experience in assorted fields of science and engineering who actually spend months or years sifting through the wreckage of an airplane to try to piece together what happened to make it fall out of the sky.

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**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\
**Post date:** [October 27, 2004, 8:26pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/26 "2004-10-27T20:26:40Z")

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> [@Brutus](#):
>
> But I do expect the plane to not start falling apart at (relatively) low-speed from the use of control surfaces. I am not a pilot (though I pretend via flight sims), but I am not aware of modern aircraft that lose their ass when you kick the rudder. (well, I know of one now)

Don’t forget that the rudder wasn’t flapping about in still air - a contributing factor was the wake turbulence which the co-pilot was trying to deal with.

> [@](#):
>
> Not to make it sound like I am trying to pin it all on Airbus or something; It does look like there is blame to spread around.

Couldn’t agree more.

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**Author:** ![blowero](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@blowero](https://boards.straightdope.com/u/blowero)\
**Post date:** [October 27, 2004, 9:57pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/27 "2004-10-27T21:57:30Z")

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> [@Brutus](#):
>
> It would be like getting in your car, accelerating to 55mph, and cutting the wheel hard left. Sure, you very well may flip over. That is not unexpected behavior for a car going at that speed trying that manuever. But you wouldn’t expect the wheels to rip off from the axle-thingees, would you?

But that was my point: They could make the entire airplane out of the same hardened steel that car axles are made of, but it would be too heavy to ever get off the ground.

And there are certainly ways to destroy a car just by driver input. If I rev the engine up to 6000 RPM and then repeatedly jam the shifter back and forth from 1st gear to reverse, the transmission is going to fall apart. Why does it allow you to do that? I would think there’s a certain amount of assumption that the operator isn’t going to do completely inappropriate things with the controls.

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**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\
**Post date:** [October 28, 2004, 12:11am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/28 "2004-10-28T00:11:57Z")

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> [@World Eater](#):
>
> The whole time I’m reading these articles, I’m having the same thoughts as the OP. The fucking plane is fly by wire. Just add a line of code that if airspeed is larger then X, limit the rudder movement by 50% or something.

Ya know I am just a poor dumb auto mechanic, but the cars I work on have speed sensetive power steering. You get more boost and easier steering at low speed than you do on the highway.  
How fucking tough would it be to modify the programing for the fly by wire system in the ScareBus to tone down a very sensitive rudder as the speed of the plane increases? If done correctly it will feel completly natural to the pilot.

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**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\
**Post date:** [October 28, 2004, 12:24am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/29 "2004-10-28T00:24:45Z")

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> [@Rick](#):
>
> Ya know I am just a poor dumb auto mechanic, but the cars I work on have speed sensetive power steering. You get more boost and easier steering at low speed than you do on the highway.  
> How fucking tough would it be to modify the programing for the fly by wire system in the ScareBus to tone down a very sensitive rudder as the speed of the plane increases? If done correctly it will feel completly natural to the pilot.

A car steering system is completely different. It functions via physical contact with the road. A single rotating tyre exerts force in one direction only - an aeroplane involves all three forces at al times.

Nobody seems to be bothering to look at the actual NTSB findings. Comparing with a car is meaningless - comparisons with ships would make more sense. But they still don’t fully explain what happened. Very very very basically - the co-pilot tried to cope with the wake turbulence from the jumbo ahead, but got it very wrong. The plane ended up twisting sideways. The resulting force on the tail was enough to take it off.

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**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\
**Post date:** [October 28, 2004, 9:16am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/30 "2004-10-28T09:16:12Z")

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> [@GorillaMan](#):
>
> A car steering system is completely different. It functions via physical contact with the road. A single rotating tyre exerts force in one direction only - an aeroplane involves all three forces at al times.

The front wheel of a car is more complicated than an aircraft rudder.

A rotating tire is required to exert force in all three dimension; drag (and if it’s on a front-wheel-drive car, it provides thrust as well), lateral force, and the normal force of supporting the car’s weight on the road.

An aircraft rudder is designed to provide lateral force only, and will have negligible effects in the other dimensions

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**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\
**Post date:** [October 28, 2004, 9:25am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/31 "2004-10-28T09:25:55Z")

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> [@Robot Arm](#):
>
> An aircraft rudder is designed to provide lateral force only

…so when the plane ends up twisted sideways, the rudder will encounter forces which it’s not designed to cope with?

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**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\
**Post date:** [October 28, 2004, 10:27am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/32 "2004-10-28T10:27:28Z")

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> [@GorillaMan](#):
>
> …so when the plane ends up twisted sideways, the rudder will encounter forces which it’s not designed to cope with?

I’m not sure exactly what “twisted sideways” means. It could be that the plane yawed to the left or right (like a skidding car), or that it rolled to either side (one wingtip higher than the other). (Or any combination of the two.)

Also, since the entire fin broke off, it seems to me that the rudder (at that airspeed and angle of flight) produced forces that the vertical stabilizer was not able to cope with.

In one of my early flying lessons, I was doing a walkaround inspection of the plane before the flight. I was new at it, and being kind of tentative around this exotic piece of machinery. Then my instructor grabbed the wingtip and started yanking it up and down, rocking the whole plane. I was a little startled, but he said that if the plane couldn’t handle what he just did, he certainly wasn’t going to fly in it. These are not fragile machines made of wood and fabric anymore.

On the other hand, even in Cessna I used for my lessons, there are limitations the pilot’s supposed to know about. There’s a white marker on the airspeed gauge (like the red on a car tachometer); if you’re going faster than that, don’t use the flaps or you’ll mess them up.

The question here is which category the Airbus rudder belongs in. Was it a bad design to have a rudder that could generate more force than the airframe could tolerate, or was that an unavoidable limitation that the crew should have known about?

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**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\
**Post date:** [October 28, 2004, 10:49am UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/33 "2004-10-28T10:49:41Z")

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The NTSB animation shows what happened: [http://www.ntsb.gov/events/2001/AA587/board\_mtg\_anim.htmhttp://www.ntsb.gov/events/2001/AA587/board\_mtg\_anim.htm](http://www.ntsb.gov/events/2001/AA587/board_mtg_anim.htmhttp://www.ntsb.gov/events/2001/AA587/board_mtg_anim.htm) Basically, the back end kicks out.

(FWIW, I know of somebody who was in a mid-sized plane stuck in the wake of a 747 for an hour. He was physically sick, and was far from the only one.)

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**Author:** ![fortytwo](https://avatars.discourse-cdn.com/v4/letter/f/f9ae1b/32.png) [@fortytwo](https://boards.straightdope.com/u/fortytwo)\
**Post date:** [October 28, 2004, 12:01pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/34 "2004-10-28T12:01:27Z")

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> [@Rick](#):
>
> …How fucking tough would it be to modify the programing for the fly by wire system in the ScareBus to tone down a very sensitive rudder as the speed of the plane increases? If done correctly it will feel completly natural to the pilot.

Most modern passenger aircraft do have a rudder limiting system. A typical system would have the pilot’s rudder input physically moving the same distance, but rudder movement is diminished ( by a ratio changer) as speed is increased. If I read it correctly the Airbus also had a rudder limiting system but the physical distance the pedals moved is also diminished as the physical distance the rudder moved is diminished. The critical difference seems to be that there was no “blowback” system where if an excessive input was made the increased air loads blowback the rudder. (As fitted to the MD- 80 for instance)  
This site has a final summary but it’s [a pdf file](http://alliedpilots.org/Public/Topics/Issues/apa587/finalsubmission.pdf)

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**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\
**Post date:** [October 28, 2004, 2:29pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/35 "2004-10-28T14:29:04Z")

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> [@GorillaMan](#):
>
> The NTSB animation shows what happened: [Page not found](http://www.ntsb.gov/events/2001/AA587/board_mtg_anim.htmhttp://www.ntsb.gov/events/2001/AA587/board_mtg_anim.htm) Basically, the back end kicks out.

Linky no work. ☹

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**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\
**Post date:** [October 28, 2004, 2:37pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/36 "2004-10-28T14:37:03Z")

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> [@GorillaMan](#):
>
> (FWIW, I know of somebody who was in a mid-sized plane stuck in the wake of a 747 for an hour. He was physically sick, and was far from the only one.)

I can’t see any reason why one plane would stay in another’s wake for an hour, assuming it could even keep up with a 747; or how a passenger on the plane would know about it if they did.

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**Author:** ![Shrinking\_Violet](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@Shrinking\_Violet](https://boards.straightdope.com/u/Shrinking_Violet)\
**Post date:** [October 28, 2004, 2:59pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/37 "2004-10-28T14:59:32Z")

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> [@Rick](#):
>
> Linky no work. ☹

[Linky fixy](http://www.ntsb.gov/events/2001/AA587/board_mtg_anim.htm)

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**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\
**Post date:** [October 28, 2004, 4:16pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/38 "2004-10-28T16:16:24Z")

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> [@NTSB](#):
>
> the vertical stabilizer was exposed to aerodynamic loads that were about twice the certified limit load design envelope and were more than the certified ultimate load design envelope

Sounds like somewhere there was a failure-of-imagination in the sense of under what circumstances you could put twice the designed “limit load” on the assembly. Apparently Airbus did figure out that it was easier than expected after the planes were already flying, but its communication of that info to the airlines failed to convey a sense of urgency (or American failed to conclude that they needed to change procedure).  
BTW the A300-600 is not a “pure” FBW aircraft – it has a computer flight control system but in the primary controls the pilots have ultimate manual authority – unlike the A320 which is FBW all the way.

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<div class="post-metadata">

**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\
**Post date:** [October 28, 2004, 4:40pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/39 "2004-10-28T16:40:31Z")

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> [@Robot Arm](#):
>
> I can’t see any reason why one plane would stay in another’s wake for an hour, assuming it could even keep up with a 747; or how a passenger on the plane would know about it if they did.

Because there’s not much option in the crowded airspace into Heathrow, and because the pilot told them what was happening.

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<div class="post-metadata">

**Author:** ![blowero](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@blowero](https://boards.straightdope.com/u/blowero)\
**Post date:** [October 28, 2004, 5:42pm UTC](https://boards.straightdope.com/t/i-pit-the-ntsbs-conclusion-regarding-flight-587/271478/40 "2004-10-28T17:42:13Z")

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By the way, why was the co-pilot flying the plane? I don’t know anything about piloting a plane, but I would think that the take-off and landing would be the more difficult tasks to handle. Wouldn’t it be the responsibility of the pilot to handle the more demanding tasks? Not that I don’t think co-pilots are capable, but just that it sort of begs the question of why they would have the designations of “pilot” and “co-pilot”, if the roles are actually the other way around.

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