What's the big deal with Rolls-Royce engines? They're some of the most advanced and safest engines around? I know when I get on a plane and see that RR insignia on the engine nacelle I have a nice warm feeling.

Not really. I know that carbon fiber composites have a higher strength-to-weight ratio than traditional materials, which has obvious advantages but doesn't really matter to the pilots. In the early days of its use, there were some problems with bonding techniques use with this material, but I'm assuming they've worked all the bugs out of this over the last few decades.


Yes, I'd agree. They are some of the most advanced, along with GE, Pratt & Whitney and Snecma.

And of course, the reality is that the cost of technology development these days is often un-affordable without collaboration.

Hey W0X0F,
I stumbled on this article earlier today,

http://callcenterinfo.tmcnet.com/new...28/5811150.htm

It seems pretty crazy that you can roll the plane so easily, are there any anti-roll "devices" build in that would prevent what happened on this flight? (obviously not on this plane, but on others).

i've obv never flown a 737 but this seems pretty absurd for a number of reasons:

- does the door lock mechanism look/feel/act anything like the rudder trim?

- how bad does your reaction time have to be to allow the situation to escalate to a 131 degree bank(!!) before you can correct it?

- i would expect out-of-control rudder to cause the plane to turn and skid wildly, not to bank 40 degrees past perpendicular to the earth. is this explanation even plausible?

Here is a photo. They are somewhat close together, but then so are the gas pedal and brake pedal on most cars!!

Yeah, I can understand the mistake of twisting the wrong knob, but not to feel the plane bank is a little sketchy, maybe there is more to this story...

The 737 crashes caused by uncommanded rudder deflections lead me to believe that a rudder going hard over will cause things to go South very quickly. Also, given the type of switch he thought he was turning, it looks like he would have easily turned the trim knob all the way to the stop almost instantly. My question would be can the trim actually cause the rudder to deflect all the way? It seems like there wouldn't be much of a use for that feature. I would assume that the trim knob can only move the rudder a percentage of it's full range. Also, how fast would it react? Does trim operate on a different mechanism than the pedals?

Thanks for everything you done here! You explain everything with such great detail with a very civilian friendly translation. I have not been all the way through yet so I apologize if these questions have been answered already.

You often rent a Cessna and fly around. I know a pilot must stay under a certain number of flight hours per week/month/year or something along those lines. Do your flight hours logged on the Cessna take away from hours you can fly at Delta? Or because one is civil and one commercial do they count separately?

Are there any current US pilots flying for legacy carriers that are dual rated? I know you can have as many type ratings as you want but are there any pilots who remain current and fly the 757/767 and may also fly a 737 at times? If not how hard is it to switch back and forth every so often as recurrent training comes up?

If you were a Captain flying a 737 or MD-88 and wanted to upgrade to 757/767 or even the 777, would you remain a Captain or would you start again as a F/O? I know Continental right now is making Captains pretty quick, roughly 6 years from hire date which would theoretically make some pretty young 767 and 777 Captains.

I'm sure I have more questions but I don't want to overload at once. Again, thanks for what you do.

There are no anti-roll devices. Pilots are supposed to be able to keep an airplane upright.

I had been sent this article by a friend earlier today and here's how I think this happened:

On the 767, we have a spring-loaded switch on the overhead panel for unlocking the cockpit door. The switch has to be held in the unlocked position and springs back to the normal (locked) position if released. On the 737, this switch is located on the right, aft, center console. (Here's a picture I found doing a Google search.)

If you look at that picture, you'll see the rudder trim to the left of the flight deck door switch. It's quite a bit larger and I'm not sure how someone confuses the two. But, like the door switch, the rudder trim has to be held one way or the other; it springs back to neutral when released. Thus, if I hold the rudder trim knob to the left, the rudder moves left until I release the knob and then stays in the new position.

So, it sounds like this guy reached down and held the rudder trim, thinking he was unlocking the cockpit door. Meanwhile, while he's holding that knob, the rudder moves more and more out of neutral. The autopilot, meantime, is compensating for the added rudder by rolling in more and more opposite aileron. On the 767, this would be noticeable as the control wheel actually tilts more and more in that direction. I assume it's the same on the 737 (being a Boeing product).

At some point, the autopilot runs out of aileron to maintain heading and it disconnects. Essentially the autopilot gives up and turns the plane over to the pilot. When it disconnects, the aileron that the autopilot was holding is released suddenly and now, with the greatly out-of-trim rudder, the plane rolls violently in the direction of the rudder trim.

We don't really use the door unlock switch very often. For one thing, we never leave one pilot alone in the cockpit. If one of us has to answer the call of nature, a flight attendant comes into the cockpit while one pilot leaves. This is so we don't have a situation where the remaining pilot becomes incapacitated and the absent pilot can't immediately get back into the cockpit. So when the absent pilot returns, the FA will open the cockpit door after looking through a peephole and verifying that it's the pilot there. Maybe it's different in Japan and they allow one pilot to remain alone up front.

(See previous answer.) The rudder trim is larger and it's round (vs. a the small knob for the door lock), but it does act similarly in that it's a spring-loaded switch. I don't think I'd confuse them.

The bank happened quickly when the autopilot disengaged and was due to the greatly out-of-trim rudder.

Yes it is. Although the uncoordinated flight should have been apparent to the pilot (control wheel dramatically tilted and the ball on the turn coordinator well out of center), the real problem occurred when the autopilot kicked off. I have no idea of the background of the pilot, but many foreign carriers are putting very low time pilots in the right seat. In some cases, they make a "pilot" out of someone with zero time and teach them enough to operate the controls. I have no idea if that's the case here, but I can't imagine this happening on one of our planes.

(You know, I should really post this disclaimer: I don't know what happened exactly. This is just the scenario I can envision with what I know of the controls.)

So what you are essentially saying is: While the Captain was in the can, the FO and an FA were locked in the cockpit and the FO decided he wanted some trim?

Seems perfectly understandable to me.

Nice pic...much better than the one I posted a link for. Thanks. You can see the rudder trim indicator just above the rudder trim knob. As you can see, full deflection is about 18 units (not sure if that's 18° of rudder or not; we always talk of units when adjusting the trim).

That reminds me of something my father used to say occasionally:

"Meanwhile back at the ranch, Tonto, not realizing the Lone Ranger was disguised as a door, twisted his knob."

(I'm sorry. This was hilarious to me as a 10 year-old.)

Not really. The trim knob moves the rudder at a measured pace and is fairly slow. On the 767, full deflection is indicated as about 18 units on the trim gauge.

In normal flight, the rudder is neutral (or very close to it). With an engine failure after takeoff (low airspeed, full power), we'll need about 15 units of trim into the good engine. It takes a few seconds to get the trim to this point holding that dial. Once we level off and pull the power on the good engine back for cruise, the rudder has to be adjusted to about 10 units. During the descent, with power even further reduced, we use about 5 units.

If we select full rudder trim, there might be a little more rudder authority using the pedals, but not much. The use of this feature is during an engine out situation. Without being able to trim the rudder, the pilot would have hold a lot of continuous pressure on the rudder pedal and after a while the leg begins to shake from holding that pedal down. (You have to experience it to know what I mean.)

The trim changes at about two units per second, so the dial has to be held about 7-8 seconds following an engine failure during climbout. Usually, the flying pilot delegate that job to the non-flying pilot ("Give me 15 units of rudder to the right.")

The trim actually sets a new neutral point for the rudder. I can't remember offhand whether or not it causes the rudder pedals to move. On some types of planes it does, but I just can't picture it on the 767 right now. I'm due to go in the sim in November, so I'll try to remember to look.

The flight time limitations only apply to commercial flying, so the flying I do on my own for fun in a Cessna doesn't count at all. However, if I go out and give a flying lesson in a Cessna, that's commercial flying and it does count. Military flying, even though the pilots are getting paid, also doesn't count in civil flight time limitations.

It's rare, but not unheard of. Usually this would be a pilot in the training department who is maintaining currency in two or more types. For line pilots, it makes no sense and would be too expensive for the company to keep the pilot current in multiple types. I think I've discussed this at greater length elsewhere in this thread.

It all depends on your seniority. You will remain a Captain if you're senior enough to hold that seat. I know one guy who recently moved from Captain of the MD-88 to right seat (FO) on the 767-400 just for better quality of life (control of schedule; better destinations; more time off).

Continental Express maybe, but I don't think anyone at mainline is upgrading that quickly, especially with the recent merger with United and all the pilots they still have on furlough. Of course, I could be wrong (wouldn't be the first time).

I thought it was strange too. Continental was the only airline, other than ExpressJet and the like, that promoted so quickly. Got the info from here - http://www.airlinepilotcentral.com/a...ntinental.html

Says this: Most junior captain hired: May 2005 (737/EWR). I believe American was the longest. Most junior captain hired: Mar 1992 (MD80/LGA)

Thanks for the quick reply!

I was going to wait a while before posting my other questions so I didn't seem like a thread hog but since it's slow at the moment, I'll go for it.

1. Would you be allowed to rent a GA plane in another country with your FAA license? You obviously have the skills but I know countries are weird about their regulations. If I were in your shoes, I would love to spend the middle day of my trip flying around Paris or other areas of interest.

2. SWA pilots fly multiple legs per day, even on the same aircraft for most of it. I know it's fairly unique compared to other US carriers but how similar or different is a domestic pilot's schedule at Delta? I am asking mainly about smaller aircraft such as MD's and 737's. If i'm not mistaken, the domestic routes you fly in the 757 are similar to your international routes with a 3 day trip, flying only one leg a day (Correct me if i'm wrong). Also do the 737 crews that fly short international routes to South America and the Carib get the same international 3 day schedule that you do going to Europe, or are those flights treated more like a domestic route where they return the same day?

3. Last question and i'll stop bothering for a while. You mentioned before that most of your weight and balance information is received via ACARS. Do the ground crews not give you loadsheets and fuel slips anymore? I presume what happens is they load the aircraft, crunch the numbers, and send the info to your FMS. Although i'm sure this information is very accurate, you would think the pilot would be the one figuring out V-Speeds etc.. I can see why they give you the CG. What about the runway slope and cost index?

I don't know but my guess would be no. I've flown a plane in Japan, but that was with the Yokota Aero Club. At the time, I was a civilian contractor to the Air Force (and Navy) and I had been granted base privileges (along with a military ID card). I flew a lot with the Hickam Aero Club in Hawaii and then I spent three months in Japan living on Yokota AB. I took several local flights, flying around Mt. Fuji and overflying downtown Tokyo at night (makes the lights of Times Square look like a kiddie show).

Domestic trips rarely have more than four flights in a day but some MD-88 trips will have more. A busy three-day trip on the 757 might have eight flights total. There are some down and back trips to Central America or the islands. The determining factor is total block time. We're limited to eight hours of block in a duty day, so if the round trip can be flown in under eight hours that's how they'll schedule it.

We don't get load sheets, but we still get fuel slips at most stations (though some, like Las Vegas, send an electronic fuel report via ACARS). All of the number crunching is done by the company after they get the data (baggage load, fuel, passengers) and they send us our final numbers via ACARS, often before we push back and more than 95% of the time before we leave the ramp. These numbers include passenger load, CG, ramp weight, flap setting and V speeds for the runway(s) in use. The computed speeds take into account current temperature, winds and, of course, airport parameters such as elevation and runway slope.

As for the cost index, that is something that the dispatcher sends us with the original flight plan. That number is chosen based on schedule and fuel burn considerations. With very favorable winds, they might choose a low cost index for fuel savings since we'll be early. If we're running late due to delays of any kind, they might bump the cost index to sacrifice fuel in an attempt to make up time. (I should probably point out to others that the cost index is simply a number which we put in the FMC which is used to compute power settings for the flight.)

Follow-up question on the 737 roll incident. The article said that the plane achieved 131.7 degrees of roll and 35 degrees of pitch at one point. On commercial aircraft (obviously it varies by aircraft) where's the point of no recovery? In an extreme roll situation like that, if you have enough altitude would it be possible to complete the roll vs stopping the aircraft's inertia then leveling off? It wouldn't be very pleasant for the FA's and pax, but they'd be alive.

Boeing barrel roll http://www.youtube.com/watch?v=-KNbK...e_gdata_player

An airplane pilot?

I only have one question... how did you end up here?

Related to EgyptAir 990:
Five minutes of research explain how this is possible, but I still don't get why it's possible. For one thing, I don't get what the contingency is that would make each yoke commanding each elevator a good thing. Also, if there's a cam that connects the two systems together, is that something that can be disengaged, or does it fail when the two yokes are pitted against each other? And out of curiosity, what happens to flight control in a split elevator situation? I suppose that if you're already hurtling downward, it's going to hamper recovery, but what happens if it occurs in level flight?

This "demonstration" by Tex Johnson of the prototype Boeing 707 (it was called the 367-80, or "Dash 80") is a great story. The plane now resides in the Steven Udvar-Hazy Air & Space Museum, just south of Dulles Airport. Here's a pic I took from one of my visits there:

I like poker and the people who play it.