Author Topic: What meens "Retard" at Airbus  (Read 1569 times)

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Offline Bogdan Ghincea

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What meens "Retard" at Airbus
« on: February 17, 2014, 10:35:04 AM »
"The reason that Airbus uses the phrase "retard" is because the Airbus fly-by-wire system does NOT physically move the "thrust leevers" when using the Auto-thrust system. That's why they are called "thrust leevers" instead of throttles. They aren't physically connected to the engines like throttle cables are so they don't move during autothrust power changes. To engage auto-thrust, the thrust leevers are moved from the TOGA (Take-Off/Go-Around) position which is full foward, or nearly all the way forward, back past the MCT (Max Continuous Thrust) detent to the CL (Climb) detent. All phases of flight and autoland approach are flown with the thrust levers in the CL detent. At touchdown in autothrust, the thrust levers are still in the CL detent...they don't move with autothrust changes in power settings. So at touchdown or thereabouts, the automated voice reminds the pilots to "retard, retard" the thrust levers out of the CL detent so engines can be brought back to idle and reverse thrust if needed. That's why it says "retard". Retard the levers out of the CL detent and back to the idle stops."

Offline Adrian Chitan

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Re: What meens "Retard" at Airbus
« Reply #1 on: February 20, 2014, 06:44:00 PM »
I love when we, as virtual pilots, get into the nitty-gritty of flying different machines. In this respect a virtual pilot is a pilot+chief mechanic as opposed to a pilot who usually doesn't get into so much detail about his apparatus. Thank you, Bogdan for opening this thread.

The fact is that this announcement comes as a two "retard" call when the flight computer has calculated imminent touch-down. The good thing is that you can ignore this and should actually be very carefull when you do it. What happens when you pull the levers to the retard notch is that the A/T disconects and the engines go to idle (quite fast in a A320). As you may have probably seen on pilotseye or live, the pilot won't retard untill he is confortable enough with the touch-down conditions of the aircraft (I've seen ignores spreading through 3 retard announcements) - you are the pilot. I think the best time to retard si when you're already at least half way on your flare. That's because the descent rate would increase dramatically after the retard so if you're not flaring, then you don't have the added cushion of the high AOA obtained in the flare. Furthermore, if you decide to go around, the engines spool up a bit laggy from idle to 40-50 % N1. So the retard is usually a comitment to landing (the announcement comes on under 20 ft AGL so you really cannot T/O again without a touch-down). On the other hand, if you don't retard, you can go nose up and the A/T will keep the app speed and you can start the GA procedures. So don't retard just because the computer tells you to. Of course, if you're coming in for an autoland, then you have to listen to the computer because he's doing everything so the A/T disconect is synchronized with the autoflare. But in manual app I sometimes find myself in a late flare condition (could'see the PAPI very well or screwed up the G/S folowing part of a manual ILS app) so I won't retard untill the descent rate matches my expectations (because the vertical velocity actually lags behind the actual flare).
I know this is known information but I thought it was the best place to write it down. Even though it's an Airbus you are still the one flying it.

Offline Bogdan Ghincea

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Re: What meens "Retard" at Airbus
« Reply #2 on: February 20, 2014, 08:03:24 PM »
Thank you Adrian for your great explanation. Those discussions are priceless. Better then the tutorials.

 

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