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Autothrottles…

January 7th, 2009 · 4 Comments

My company is in the process of developing a program that will revolutionize the way we navigate our aircraft from one point to another. We are transitioning to a “performance-based” navigation program, which will allow us to further automate the following of our planned flight path in all phases of flight. Essentially, we pilots will be allowed to fly new routing based upon the performance capabilities and navigation ability of our aircraft.

The process to certify the fleet is a long one, and I sure am not ensconced in the planning and execution of the new program. I’m merely a line pilot who completes the required training modules, reads the required manual revisions, and takes the required simulator training as the program gets rolled out in several phases.

As part of the first phase of the implementation of the performance-based navigation program we’re moving towards, my company has decided to get with the times and switch on the autothrottle systems that had lain dormant (with a big INOP placard slapped on them) since each of the airplanes was first delivered.

“Why is it,” you ask, “that you’ve been flying these airplanes since the mid 80′s without using all the wonderful automation that was part of the aircraft when they were delivered?” My answer to that question is a hearty, “I have no idea!”

The Boeing 737 autothrottle system isn’t unlike every other airliner’s autothrottle system. It is essentially a computer that controls a set of servos that move the thrust levers automatically in response to pilot input on the autopilot mode control panel and with reference to the aircraft’s performance. It can be used in all phases of flight from takeoff to rollout, and will maintain speed/Mach or vertical speeds set by the pilots in climbs, level flight, and descents. For the first phase of the perf-based nav, we get to use the autothrottles above 10,000 feet only, and only after the successful completion of about three hours worth of computer-based ground training. This will give us five or six months of “getting used to the system” time (also known as “what the hell is it doing now?” time) before we take some more classes and start using the A/T for takeoffs as well.

The system gets turned on (supposedly) on January 12. I’ll be reviewing the study books before then to refresh my memory of the system.

Tags: Airliners

4 responses so far ↓

  • 1 PlasticPilot // Jan 7, 2009 at 9:15 pm

    If I may ask, was the autothrottle simply “de-activated”, or was the computer not installed, to reduce weight, and lower the buy price ?

    My two cents…

  • 2 gcalvin // Jan 7, 2009 at 9:21 pm

    Was there an opinion in there somewhere I missed?

    As far as I know, the AT system was installed when the planes were built by Boeing and deactivated after they were delivered to the airline I work for. I know for sure that was the case for the -700′s we operate. The 300′s might be another situation altogether.

  • 3 Sam Weigel // Jan 10, 2009 at 6:12 pm

    The JungleBus comes standard with autothrottles and we are, of course, encouraged to use them full-time, albeit with the usual advice to turn off the automation just often enough to be proficient should it fail. I make it a point to fly at least one approach per trip without them and encourage my FOs to do the same; some are a bit hesitant as we have a few Captains that are rather militant about autothrottle usage.

    I’ve had a few times that the autothrottles have been MEL’d, and it makes you realize just how lazy they’ve made you. I’d imagine it’d be worse if you hadn’t turned them off in several months….

  • 4 gcalvin // Jan 19, 2009 at 1:57 am

    Well, the actual turn-on date for our A/T systems was the 13th. I flew that day, but in an older -300 that did not have an operative autothrottle system.

    As of today, I’ve flown two days and seven legs in A/T equipped aircraft. Having practical experience with the system now brings a higher level of understanding of the operation. There have been a couple “What’s it doing now?” instances, but nothing excessively out-of-whack.

    Using the A/Ts has caused the two of us to pay more attention to the operation of the airplane than we have in a long time, however. Not because we didn’t pay attention before, but because we’d gotten used to certain outcomes being expected of certain actions that we took. Now, with the A/Ts working, we’ve got a need to pay closer attention to ensure they’re doing their job correctly. It would be very easy to let yourself fall out of the loop.

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