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HAWK21M
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RTO Condition U/s ASI

Tue Jul 28, 2009 5:00 pm

Can a Flag on the F/O side Mach/ASI on Take off warrant a RTO or would the Stdy ASI be monitored.Considering a B757.What is the crew response normally.
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DescendVia
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RE: RTO Condition U/s ASI

Tue Jul 28, 2009 7:48 pm

Quoting HAWK21M (Thread starter):

I guess it would depend on the regime.

For example, you'll usually reject for everything before 80 knots. From 80 knots to V1 you should only do it for a engine fire, failure, PWS, or airplane becomes un-flyable.

I personally would consider airspeed un-reliable as a un-flyable condition.

[Edited 2009-07-28 12:54:27]
 
Mir
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RE: RTO Condition U/s ASI

Tue Jul 28, 2009 10:33 pm



Quoting DescendVia (Reply 1):
I personally would consider airspeed un-reliable as a un-flyable condition.

As would I. I'd abort for it at any speed below V1. Sure, you have two backups, but they're all using the same sort of sensor, and you never know if there is a certain condition that affects those sort of sensors - if so, your other ASIs may be quitting soon. Not a situation you want to have in the air.

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HAWK21M
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 5:28 am



Quoting Mir (Reply 2):
but they're all using the same sort of sensor

Different sources of DADC/Pitot/static,selectable by ISSS depending on the Instrument.
But I guess the phase would not warrant playing around.
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
movingtin
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 2:11 pm



Quoting DescendVia (Reply 1):
I personally would consider airspeed un-reliable as a un-flyable condition.

1 Failed indicator is NOT an Un reliable A/S condition.
 
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HAWK21M
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 5:23 pm



Quoting Movingtin (Reply 4):
1 Failed indicator is NOT an Un reliable A/S condition.

With an option of Speed tapes on both EADIs + Two ASIs & 1 Stby ASI should not be a problem to fly.However if the flag appeared on T/O roll,desicion time is limited.
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MEL.
I may not win often, but I damn well never lose!!! ;)
 
DescendVia
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 7:58 pm

Quoting Movingtin (Reply 4):
1 Failed indicator is NOT an Un reliable A/S condition.



Quoting HAWK21M (Reply 4):
desicion time is limited

  

Why even risk it? Its always safer to be on the ground second guessing, then in the air with 1 failed indicator possibly turning into a complete ADC failure. You have no idea why the ASI failed and its not the the time to try to figure it out.

If it was not a big deal, just start over again.

[Edited 2009-07-29 13:10:59]
 
CosmicCruiser
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 11:36 pm



Quoting DescendVia (Reply 6):
Why even risk it? Its always safer to be on the ground second guessing, then in the air with 1 failed indicator possibly turning into a complete ADC failure. You have no idea why the ASI failed and its not the the time to try to figure it out.

If it was not a big deal, just start over again.

I think you were correct when you said it depends on regime(speed). No high speed abort is a good thing in a heavy jet and the consequences may be worse than flying. Something else to consider is it night , day, VFR or IFR.
 
lowrider
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RE: RTO Condition U/s ASI

Wed Jul 29, 2009 11:53 pm



Quoting HAWK21M (Thread starter):
Can a Flag on the F/O side Mach/ASI on Take off warrant a RTO or would the Stdy ASI be monitored.Considering a B757.What is the crew response normally.

Prior to 80 knots I have and would again rejected for this very reason. A low speed reject is a relatively low risk event. Certainly lower than taking the aircraft airborne with an indication problem of an undetermined source. Above 80 knots we consider it to be a high speed reject. These are a higher risk event and are only attempted for the most serious reasons. An inop ASI is not dangerous enough to risk it. Better to take the aircraft airborne at that point.

Of course, the pilot monitoring should have noticed this right away, but that can be dealt with when all the big parts are safely stationary
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HAWK21M
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RE: RTO Condition U/s ASI

Thu Jul 30, 2009 9:10 am

A related query.A snag before chocks off is a Snag.A snag after Chocks off needing a return to the bay is an Incident,involving paperwork,investigation & SSCVR/SSFDR data downloads.
Thats how its here.How is it at other places?
regds
MEL.
I may not win often, but I damn well never lose!!! ;)
 
movingtin
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RE: RTO Condition U/s ASI

Thu Jul 30, 2009 12:59 pm



Quoting CosmicCruiser (Reply 7):
No high speed abort is a good thing in a heavy jet and the consequences may be worse than flying.



Quoting Lowrider (Reply 8):
A low speed reject is a relatively low risk event. Certainly lower than taking the aircraft airborne with an indication problem of an undetermined source. Above 80 knots we consider it to be a high speed reject. These are a higher risk event and are only attempted for the most serious reasons. An inop ASI is not dangerous enough to risk it. Better to take the aircraft airborne at that point.

Exactly, I would not want to be out on a closed runway trying to rhino jack a heavy with a couple of blown tires just because a F/O A/S flag appeared after 80 KTs. not to mention all the other insp that will have to done after you clear the runway.
 
lowrider
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RE: RTO Condition U/s ASI

Thu Jul 30, 2009 1:12 pm



Quoting HAWK21M (Reply 9):
A related query.A snag before chocks off is a Snag.A snag after Chocks off needing a return to the bay is an Incident,involving paperwork,investigation & SSCVR/SSFDR data downloads.
Thats how its here.How is it at other places?

What do you mean by a snag? Are you talking about an incident involving aircraft damage or a simple write up? A write up before block out must be resolved prior to block out. If something happens after block out and the item is not deferable or requires special proceedures to defer it, then you must return to the gate. If no special proceedures are required, continue and treat it as an en-route failure.
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HAWK21M
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RE: RTO Condition U/s ASI

Thu Jul 30, 2009 6:49 pm



Quoting Lowrider (Reply 11):
What do you mean by a snag? Are you talking about an incident involving aircraft damage or a simple write up

A Simple write up after chocks off & if the Aircraft returns back to the gate without completing its intended journey.....Its termed an Incident out here.
regds
MEL.
I may not win often, but I damn well never lose!!! ;)

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