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Just out of curiosity, I want to ask why do we have to check that the speed brakes lever is retracted during a GPWS (Ground Proximity Warning System) maneuver using the A320 memory items?

It clearly says in the F/CTRL SYS that the SPD BRK is inhibited if the thrust levers are above the MCT detent.

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Because that is how American Airlines Flight 965 went down.

Long story short, the pilots deployed the speed brakes to increase descent rate during approach, and did not notice they were off course. The GPWS warning sounded. The pilots reacted within one second. They did everything they could - except they did not retract the speed brakes. They crashed.

Why is it a memory item? Because GPWS means imminent terrain contact. You don't want to wait around for some automatic mechanism to retract the speed brakes for you. Let alone take the chance of that mechanism failed. You do it. NOW.

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  • $\begingroup$ But that was a Boeing 757, not an Airbus. The A320 should automatically retract the speedbrakes. $\endgroup$ – Bianfable Oct 3 '19 at 13:26
  • $\begingroup$ @Bianfable yup, it should. But when the GPWS red warning light is flashing, it is not time to take chances. And it doesn't really take that long to execute, so there is no downside. The glance takes a split second. And if needed, the handle is right next to the throttle. $\endgroup$ – kevin Oct 3 '19 at 13:35
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    $\begingroup$ @Bianfable your comment on Dave's answer mentioned the speedbrakes stay retracted until the inhibition condition disappears, I'm guessing the logic in checking the lever is to make sure that speedbrakes don't pop back up again unintentionally once inhibiting conditions are no longer present. $\endgroup$ – Jpe61 Oct 3 '19 at 13:37
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    $\begingroup$ @Jpe61: After the automatic inhibition (retraction), the lever needs to be manually moved to retracted position for at least 5 seconds before extending again. $\endgroup$ – ymb1 Oct 3 '19 at 16:03
  • $\begingroup$ @ymb1 that's not what I'm after. I was referring to Bianfables comment on Dave's answer, as it gave the impression that speedbrakes would automatically extend back if they were retracted by GPWS, and the "situation" was normalized and speedbrake lever was still in extended position. $\endgroup$ – Jpe61 Oct 3 '19 at 17:27
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I think you are missing a key term, I don't have the official SOP's on hand but many of the secondary references are using the same verbiage:

Speed brake extension is inhibited under the following conditions...

  • Either thrust lever is above MCT

In other words you cant extend the speed breaks if the throttle is over the MCT but if they are extended they may remain that way.

So why is it a memory item... If you are to low or in danger of hitting an obstacle the general solution is to CLIMB and the best climb rates wont be achieved with speed brakes out as they generally spoil lift so in the event of a GPWS alarm you will want to retract the speed breaks and climb.

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    $\begingroup$ The FCOM says "If an inhibition occurs when the speedbrakes are extended, they retract automatically and stay retracted until the inhibition condition disappears [...]." And "Thrust Levers above MCT position" is listed as an inhibition condition, so they should retract automatically. $\endgroup$ – Bianfable Oct 3 '19 at 12:57
  • $\begingroup$ @Bianfable Is there a case where you would climb with the throttles not in MCT? $\endgroup$ – Dave Oct 3 '19 at 16:09
  • $\begingroup$ I found the steps in this QRH online (see p. 66) and they clearly say "THRUST LEVERS ... TOGA, SPEED BRAKES LEVER ... CHECK RETRACTED", so they are above MCT and one should still check the speed brakes for some reason. $\endgroup$ – Bianfable Oct 4 '19 at 9:49

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