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Author
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Topic: Shuttle landings: CDR, PLT and autopilot
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Flying Dutchman
Member Posts: 161
From: Heemstede
Registered: Jan 2007
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posted 11-09-2007 08:10 AM
   
Hi can someone help me out? When the CDR is flying the shuttle on hand below mach 1 there is a certain point one is saying "on at the 90". That has something to do with the flight pattern to reduce excessive speed, but what does it exactly mean? I would furthermore like to know, what the task of the PLT is during landing. I think CDR is flying the shuttle on hand... what is PLT doing? And does anyone know if there have been landings made on autopilot? |
onesmallstep
Member Posts: 1310
From: Staten Island, New York USA
Registered: Nov 2007
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posted 11-09-2007 08:32 AM
I believe the shuttle PLT monitors the displays and drops the landing gear right before touchdown. On STS-120, CDR Melroy allowed PLT Zamka to take over the controls for a spell. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 11-09-2007 09:22 AM
On at the 180 and on at the 90 I am pretty sure are references to the heading alignment cones. These are a pair of invisible radio aids on each side of the runway and the shuttle uses them to help maintain the proper turn during the glide. They appear as like a large circle to a pilot on one of the CRTs. They use these aids to maintain the proper turn.Think of it as like a hairpin turn on a race course. A race car wants to hit the proper apex of the turn and the shuttle is the same way to a certain extent. If the shuttle tries to turn too steep, then it won't be situated right for the final. If it turns to shallow, then it might lose too much energy and land short. On at the 90 and on at the 180 just mean that the shuttle is on at the proper track with the proper speed at both 90 degrees from their entry point to the final turn and 180 degrees (when they should roll out on final). As for the pilot's role, he indeed does do certain callouts and manages systems onboard if they need it. He can take over flight control if needed and I believe pilots now also do one minor role reversal manuever late in the flight to get an idea of how the controls work before the CDR takes over for landing. And yes, they also drop the all important landing gear. The gear can only be deployed once as it has no retract system and it is the pilot's job to drop it at just the right time. Too soon and it is excess air drag, too late and it might not be deployed fully when the shuttle hits the runway. |
kimmern123
Member Posts: 83
From: Norway
Registered: Dec 2006
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posted 11-09-2007 04:19 PM
On at the 180 means the orbiter is on the nominal trajectory with 180 degrees to go on the HAC. On at the 90 is the same, but is called out when the orbiter has 90 degrees left of the HAC-turn.I think it has occured that the CDR has gotten a call like "Low at the 90" or something. If my memory serves me correctly it happened on STS-98. No big deal though as it's often just off by a small margin and nothing major. Too low however would give the orbiter too little energy to manage the landing |
Flying Dutchman
Member Posts: 161
From: Heemstede
Registered: Jan 2007
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posted 11-09-2007 05:03 PM
Thanks you for helping me out !! Wow everyday I still learn !! thanks |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 11-09-2007 11:15 PM
Kimmern got it right on the terms. It is indeed 180 and then 90, before the final (which I suppose could be considered on at the zero). |
OV-105
Member Posts: 816
From: Ridgecrest, CA
Registered: Sep 2000
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posted 11-10-2007 03:10 PM
I think STS-37 was the first to ever get a low on energy. They had a really bad head wind come up really late in the landing. |
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