qslinger
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SQ 747-400: No Speed Brakes Deployed On Landing.

Fri Aug 17, 2007 9:22 am

Hi,


I flew SQ 747-400 (Star Alliance) fromSingapore to Auckland. The plane was packed to capacity and upon landing at AKL, the pilot did not deploy the speed brakes. I am assuming that the speed brakes(spoilers) are deployed automatically, but in this case the pilot did not use the speed brakes.

Question is,

When are the speedbrakes necessary? Any particular reason a pilot would not use them?

Regards

Qslinger
Raj Koona
 
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Jetlagged
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Fri Aug 17, 2007 11:20 am

Sounds like a question tailor made for PhilSquares! Speedbrakes are routinely used on landing, and I can't think of a reason not to use them. If the speedbrake lever is not armed and reverse thrust is not used then the speedbrake would not deploy on landing.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
PhilSquares
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Fri Aug 17, 2007 11:47 am

Normal SOP is to arm the spoilers for auto deployment. The auto function will occur "On the ground, the Speedbrake lever stop retracts allowing the Speedbrake lever
to be moved fully aft to UP position. All six spoiler panels on each wing extend to
their full travel positions.
When the Speedbrake lever is in ARMED position, thrust levers 1 and 3 are near
the closed position, and the main landing gear touch down, the Speedbrake lever
is driven to UP position, extending all spoiler panels.
If the Speedbrake lever is in DN position with the main gear on the ground and
thrust levers 1 and 3 near the closed position, and reverse thrust levers 2 or 4 are
pulled up to idle detent, the Speedbrake lever is raised out of DN detent and driven
to UP position. This provides an automatic ground spoiler function for RTO and
provides a backup automatic ground spoiler function for landing when the
Speedbrake lever is not armed during approach.
For go-around protection, if Thrust lever 1 or 3 is advanced from closed position,
the Speedbrake lever is driven to DN position. This occurs whether ground
spoilers were automatically or manually extended. The Speedbrake lever can be
manually returned to DN position.
The EICAS advisory message SPEEDBRAKE AUTO indicates a fault which
could result in the loss of the automatic ground spoiler function. If the Speedbrake
lever is in ARM position, the message indicates a fault which could result in
inadvertent spoiler extension in flight. No inadvertent spoiler extension can occur
with the Speedbrake lever in DN position. The spoilers can be operated manually."

What the speedbrakes do is to "spoil" the lift and put more weight on the MLG, thus braking efficiency is increased. At the landing weights for the 744 it's not a big deal. Some aircraft have a very "touch" armed position and having the lever in the armed position isn't quite there. If reverse isn't used then you have a situation where the spoilers won't deploy.

Bottom line: No big deal....
Fly fast, live slow
 
BAE146QT
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sat Aug 18, 2007 2:17 am

Phil,

Is it possible that the PIC didn't want to stop quickly? Perhaps his place at the terminal meant that being further down the runway was preferable and he wanted to get there without using more taxiways and turns than necessary?

I know it's difficult to speculate on a given case, (it would really only be true if either rwy 23 was the active, for example, since the passenger terminals are closer to the rwy 11 end) but that does happen for the sake of fuel/convenience, doesn't it?
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PhilSquares
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sat Aug 18, 2007 10:00 am

Quoting BAe146QT (Reply 3):
Is it possible that the PIC didn't want to stop quickly?

Well the issue is what the SOP directs. It's very clear about arming the speedbrakes. Using idle reverse and no autobrakes would accomplish the same thing.
Fly fast, live slow
 
9VSIO
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sat Aug 18, 2007 6:05 pm

This will probably sound silly, but are spoilers on the MEL? Are the certification stopping tests done without the help of spoilers?
Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
 
PhilSquares
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sat Aug 18, 2007 7:02 pm

Quoting 9VSIO (Reply 5):
This will probably sound silly, but are spoilers on the MEL? Are the certification stopping tests done without the help of spoilers?

No relief for the spoilers in the MEL. There is relief for the auto function.
Fly fast, live slow
 
Tristarsteve
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sat Aug 18, 2007 10:41 pm

Quoting PhilSquares (Reply 6):
No relief for the spoilers in the MEL. There is relief for the auto function

The A320 series allows one pair of spoilers to be inop.
 
jhooper
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Sun Aug 19, 2007 7:12 am

I can only speak for my airplane, and we deploy the spoilers as a matter of procedure, i.e. it's not our choice--we have to use them. I assume all other large airplanes and organizations operate the same way.
Last year 1,944 New Yorkers saw something and said something.
 
qslinger
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Tue Aug 21, 2007 8:17 pm

Quoting 9VSIO (Reply 5):
but are spoilers on the MEL?

Whats a MEL?
Raj Koona
 
fr8mech
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RE: SQ 747-400: No Speed Brakes Deployed On Landing.

Tue Aug 21, 2007 8:32 pm

Quoting Qslinger (Reply 9):
Whats a MEL?

"Minimum Equipment List". It is a list of equipment or systems that may be inoperative on an aircraft and the aircraft still be considered airworthy.

The Master MEL is produced by the manufacturer. Airlines are free to use whatever provisions they wish, with the FAA's (other other regulatory body's) concurrence. They then 'write' their own MEL.

Usually items in the MEL are broken down into 4 categories:
-A. Must fix within a certain set of flight hours or days
-B. Must fix within 3 days
-C. Must fix within 10 days (the most common)
-D. Must fix within 180 (I think) days (the least common)

The auto speedbrakes on most aircraft can be placed on MEL as long as manual deployment works correctly. Some aircraft do allow symmetrical spoilers to be inoperative. These are both category C items.
When seconds count...the police are minutes away.

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