bigphilnyc
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Gear Problems; Why Return?

Sat Sep 13, 2003 3:01 pm

Also fomr reading maintenance records, I notice that whenever a plane has trouble iwth its gear retracting properly, they always return right back.

Why is this? Is there really a danger to flying with the gear partially or fully down?

If they can land ok at the airport they just departed form, why not at the one they are going to?

-Phil
Phil Derner Jr.
 
flyf15
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RE: Gear Problems; Why Return?

Sat Sep 13, 2003 3:05 pm

One main reason is that having the gear down creates excess drag. Excess drag equates to greater fuel burn and therefore less range. They might not have enough fuel to get to their destination. There are also other operational considerations such as maximum speeds. Other things are considered, such as why the gear isn't retracting -- maybe it is part of a bigger problem, they may have just departed their hub (where they could quite possibly have a maintaince base), etc.
 
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Bruce
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 12:51 am

YOu cannot operate a jet with gear down at normal speeds, simple as that. The gear strut would probably just break off its not designed for that kind of pressure. Not to mention the greater fuel burn..of course the fuel burn would be reduced when the wheels fall off but then landing might be a tad difficult and unpleasant for the passengers!


bruce
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
AAR90
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 1:10 am

I notice that whenever a plane has trouble iwth its gear retracting properly, they always return right back.

Common sense. If you have problems retracting the landing gear, you attempt to return the gear to its original (lowered) position. If successfully lowered, you do not attempt to raise the gear again. I am no longer paid to be a test pilot, and the pax did not pay to ride a test flight.  Wink/being sarcastic With the gear now stuck in the "down" position, it very rarely makes sense to go any significant distance from where you currently are.... uses lots of gas.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
OPNLguy
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 4:57 am

...so you don't end up like this:


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ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
ThirtyEcho
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 8:22 am

The gear strut would probably just break off its not designed for that kind of pressure.

Oops, Bruce; you got that wrong. Its not the gear that is the problem, its the gear doors. There have been numerous instances of the gear being operated at high speed (to correct an out-of-control overspeed) with nothing untoward happening to the gear struts. Its the gear doors being blown off, distorted or damaged that causes the problem.

In general, you have to ask yourself why the gear aren't operating correctly; this could be a symptom of something far more serious. Best to take it to the barn and find out on the ground.
 
JBirdAV8r
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 8:47 am

Aside from the obvious speed restrictions...it just seems like common sense to me.

When the gear malfunctions in ANY way, you come back around and land. No use risking causing additional malfunctions by flying around any longer than you have to with the gear in an unusual condition.

@ThirtyEcho:

Bruce is partially correct. Vle, or maximum landing gear extended speed, is almost always different (higher) than Vlo, or maximum landing gear operating speed. The gear doors really only come into play (on MOST aircraft) when the landing gear is in transit. There is still a speed restriction with the gear extended, though, because the added pressure of higher-speed flight would still be very hard on various components of the gear.
I got my head checked--by a jumbo jet
 
OPNLguy
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 10:02 am

At normal speeds, the gears are pretty sturdy... At higher speeds...

Back in 1979, TWA had a 727-100 hit .96M in a dive from FL390, and they extended the gear during the recovery sequence... (The "Hoot Gibson" Affair). The paragraph below is from the NTSB's report:

"Both main gear landing doors and their operating mechanisms were damaged extensively and a hydraulic line was ruptured. The sidebrace and actuator supports beam on the right gear were broken; the support beam for the left gear was intact. The uplock for the left gear was bent. The secondary wing skin panels above both actuator support beams were buckled upward."

They did get an unsafe gear indication as they headed to DTW, but a fly-by showed the gear appeared down. They landed OK. If the gear can survive .96M, anything less would appear to be a non-issue. (Gear doors are another matter).

BTW, this is NOT the same "Hoot Gibson" who was a NASA space shuttle pilot; they're two separate people...  Big grin



ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
CX Flyboy
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RE: Gear Problems; Why Return?

Sun Sep 14, 2003 5:17 pm

I remember a certain manager/pilot of a certain famously miss seeing a gear pin during a walkaround and then flying their short flight with the gear down the whole time creating a lot of noise and drag. They had the fuel for it, but still...whoops!
 
buckfifty
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RE: Gear Problems; Why Return?

Mon Sep 15, 2003 12:10 am

I remember a certain manager/pilot of a certain famously miss seeing a gear pin during a walkaround and then flying their short flight with the gear down the whole time creating a lot of noise and drag. They had the fuel for it, but still...whoops!

I get reminded of that story time and time again...

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