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1. 10:07 AM - Re: Lost Hydraulic pressure in flight (yourtcfg@aol.com)
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| Subject: | Re: Lost Hydraulic pressure in flight |
BILL.............I never thought I would be disagreeing with you, but in th
is case I respectfully do. The factory is working on a solution for this p
roblem as we speak. The hyd system in all twisty gear Commanders has a fla
w. There have been many commanders damaged and at least one totaled (680FL
P in Canada) because of this. There have also been many more saved because
the pilot had the breaker pulled when the system failed, most recently, Ji
mmy Rodriguez in San Juan (500B, N106VC, S/N 1). In a perfect world, ever
y pilot would constantly monitor the hyd press gauge and pull the circuit b
reaker when they see the press falling. In the REAL world, most pilots sim
ply don't devote that amount of attention. Further, as the airplanes are m
odified and upgraded, the hyd press gauge is oft times moved and placed on
the panel where it is difficult for the pilot to see. By the time the nose
gear drops (assuming loss of fluid) the aux pump will have long ago pumped
the reserve fluid overboard, leaving the pilot with no steering or brakes.
Leaving the aux hyd pump energized allows a loss of press for any reason,
including loss of fluid, to turn the pump on and empty the reserve that Te
d Smith intended to be used for this emergency. It is a flaw or an oversit
e that has had dire results. As you said, the aux hud pump has no function
except to operate the brakes and steering in an emergency. (It will raise
and lower the flaps, but should not be used to do so in an emergency, only
on the ground). Pilots should ALWAYS check the hyd press gauge before lan
ding. If the press is low, then and only then enable the aux pump. This w
ill ensure there is adequate fluid in reserve to stop and steer the airplan
e. Caution should be used after landing on piston airplanes (no reverse) a
s the steering and brakes could fail if fluid is still being lost. Best to
clear the runway and call for a tug. All modern Commanders have dual eng
ine pumps and the odds of losing both in a single flight is extremely low.
Losing hyd press is almost always form a loss of fluid. Having the aux pu
mp enabled can only make things worse in a real failure. Thanks for all yo
u fine work in Commanderland Bill. Jim Metzger 360-903-6901
-----Original Message-----
From: BillLeff1 <BillLeff1@aol.com>
Sent: Tue, Feb 14, 2012 10:54 am
Subject: Re: Commander-List: Lost Hydraulic pressure in flight
No No No! The aux hydraulic pump should only be pulled during an emergency
. It is intended to be operational if you loose hydraulic pressure during t
ake off and landing.
During take off and landing if the hydraulic system fails due to a broken l
ine in the landing gear system the main system will fail (the first indicat
ion of a failure of the main system is the nose gear extending) but there i
s a reserve that only supplies the brakes, nose wheel steering and flaps. T
his system will be available during the landing roll if the main system fai
ls.
You do not have time to reach over and reset a CB or turn on a switch (this
would require a field approval) once you realize that you have a problem.
However, if you pull the aux hyd CB as soon as you recognize the hydraulic
system failure you will preserve the aux pump supply. This should me a memo
ry item as far as emergency check list are concerned.
The aux hydraulic pump has no function in extending the landing gear. So, y
ou should wait until you are on short final to push it in. On the other han
d, why do you need brakes in a 690 anyway!
Ted Smith was a smart guy, don't second guess his intension's about how to
operate his systems.
Bill Leff
In a message dated 2/14/2012 1:04:22 P.M. Eastern Standard Time, nick@conta
iner.com writes:
Thanks for your comments
From: owner-commander-list-server@matronics.com [mailto:owner-commander-lis
t-server@matronics.com] On Behalf Of yourtcfg@aol.com
Sent: Monday, February 13, 2012 8:10 PM
Subject: Re: Commander-List: Lost Hydraulic pressure in flight
That is what I always recommend. There should be a circuit breaker/switch,
similar to the Beechcraft switch's, installed. Congratulations on handlin
g the emergency well, it doesn't always have a happy ending!! jb
-----Original Message-----
From: nick <nick@container.com>
Sent: Wed, Feb 8, 2012 9:16 am
Subject: Commander-List: Lost Hydraulic pressure in flight
Dear Commander Gurus=99 :
We started to lose hydraulic pressure in my 690A commander .Pressure went f
rom 900# to 500# . We followed emergency procedure which calls for the pull
ing of the breaker for the aux. hydraulic pump and continued the flight .Th
en as is procedure we pushed in the breaker and the gear came down without
a problem..
My question is why not fly with the aux. hydraulic breaker pulled all the t
ime? This would prevent loss of all fluid if you did not catch the loss soo
n enough
Any comments ? Nick N674NM
From: owner-commander-list-server@matronics.com [mailto:owner-commander-lis
t-server@matronics.com] On Behalf Of Barry Collman
Sent: Wednesday, February 08, 2012 4:08 AM
Subject: RE: Commander-List: SALVAGE OR DERALICT COMMANDER
Hi Moe,
Last I knew:
N55GL, 680F(P) s/n 1200-104, was derelict at Berry Hill, Georgia. Info from
a photo taken in January 2011.
N27GA, 680F(P) s/n 1212-111, was derelict at Corona, California. Info from
a photo taken in February 2011.
N70QT, 680F(P) s/n 1208-109, was being parted out by Mountain Air LLC., Mar
ion, Iowa following its accident in July 2009.
If none of these prove fruitful, I=99ll try some of the other Models.
Very Best Regards,
Barry
From: owner-commander-list-server@matronics.com [mailto:owner-commander-lis
t-server@matronics.com] On Behalf Of Moe Mills
Sent: 08 February 2012 07:03
Subject: Commander-List: SALVAGE OR DERALICT COMMANDER
COMMANDERLAND'
DOES ANYONE KNOW OF A
680t
680flp
680F(p)
THAT IS EITHER DERALICT OR BEING PARTED OUT?
THANX!
Moe Mills
N680RR
680F(p)
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