Hello to all, in PIC why does the speed brake automatically retract on the ground when you throttle up after exiting the runway or throttle up for a go around after touchdown? Doesn

If i remember correctly, when auto-spoilers are armed for landing, or when the spoilers are deployed as a result of the selection of reverse thrust, the spoilers are restowed when the thrust levers are first moved past foreward idle.The advantage of this system is easily seen in the cas of the go around.In terms of why retraction doesn't occur in flight if the levers are moved out of idle, i suppose it may be because during some descents, power may have to be increased for sufficient airflow for things such as packs or anti-ice. The spoilers would thus have to remain deployed to stay on the vnav path.hope i've helped

Hi,This is exactly as it is in real life.The logic doesn't prevent the usage of speed brake in the air, even though thrust is applied at the same time.See the Cali 757 accident report, where that same logic, or more closely the lack of it, was maybe PARTLY responsible why the escape maneuver didn't succeed:http://www.rvs.uni-bielefeld.de/publicatio...li/calirep.htmlIn the ground, however, the logic is such that the speed brake is retracted when power is applied.Re: the go-around situation. That's how it should be. It's not an unseen thing in the go-around for the wheels to touch the runway. Understandably, the speed brake would extend (when armed) then, and then prevent the normal go-around (killing the lift), if there wasn't such a protective feature in the logic that retracts the panels when power is added and the mains are on the ground.So in short: It works exactly as it should.Tero

Tero,Thanks for the link to the accident report ... this is VERY VERY CHILLING READING ... in fact I could not stop reading until I finished. It's very clear that "automation" is not always 100% effective and that there is no substitute for the "old manual ways of doing thngs". The most scary part of this is the observation from research about people not wanting to change an approach to a problem once they have started, or admitting there might be an issue, even when all other circumstances should lead one to do so. Further it is very clear that ROUTINE should NEVER be routine. Even with two people and two brains working on a problem ... it's clear that too many things were missed .. continuing a descent while being LOST, relying on automation which provided ambiguous and incorrect information, so many circumstances simply ganged up on this poor flight crew and all of those people ... Amazing stuff ... thanks for sharing that.Regards,Paul BenoitKSAN

My friends at AAL felt that if the aircraft had been a "Jurassic Jet" (727) the accident would not have happened. Too much automation is not always a good thing.Scott

Yeah well maybe that 727 would have crashed a week earlier because a faulty VOR station guided that aircraft into a mountain somewhere else...Automation and glass cockpits were invented to increase safety and the statistics show that it was successful!Of course you will always find that there are exceptions..."that A320 that crashed into the trees during that airshow wouldn't have crashed if it would have been a boeing...""but then again that alaskan 737 wouldn't have crashed if it had been an A320..."I guess the most important thing is that you know your aircraft well!At least until we can beam people!Regards,Mark

Yeah that's a really scary CVR transcript read. I think the comms between Cali ATC and the plane also played a huge role in that crash though as well as the overreliance on automation and lack of cross checking between the two pilots. The term "direct" obviously meant something very different to this controller in his non-radar environment than it normally does to a pilot flying in the US. That coupled with not realizing that the attempt to enter the marker fix into the FMC resulted in a way off course waypoint is really what did it.Check out the AeroPeru 757 one too where the static ports were covered up, giving all sorts of erroneous air data - those guys had no idea what the actual problem was. If they'd relied on the EADI, radio altimeter, and the ILS, they probably could have made it back to Lima...