Fine example of Tarver Engineering release for service

"mah" wrote in message
...
Rich Ahrens wrote:


Yes, those static ports are pretty unreliable! :-)

All those moving parts...

Yep, I've got a can of static port grease on the shelf next to my
bottle
of horn fluid and the box of muffler bearings.

Well the only tiny grain of truth in that statement is that a static
port can be occluded by a
foreign object. On the ground this can be something like an insect
setting up housekeeping
in it, in flight ice is probably the biggest risk factor. Since loss of
the static port will bugger up
3 basic flight instruments (altimeter, ASI and VSI) this is non-trivial.

The CO

"Gord Beaman" ) wrote in message . ..
mah wrote:

Tarver Engineering wrote:


The sole reason for using a static port is so the guts can be removed from
the pitot tube, in order to improve reliability. A pitot port produces no
static pressure datum.


Just as an example, when the aircraft is sitting still on the ground -
airspeed = 0. Since the pitot and static ports are in the same state,
doesn't that imply that static pressure is present at the pitot port?

MAH

Sure it's there, but it's there only until the a/c starts to
move. It's then no longer 'static pressure' because it's been
raised by the ram effect of the movement.

That's why you now need a 'static port' to supply the static
pressure to use as a reference. Is it really that difficult to
see?!?


where are the mud bees?

"The CO" wrote in
:

Well the only tiny grain of truth in that statement is that a static
port can be occluded by a
foreign object. On the ground this can be something like an insect
setting up housekeeping
in it, in flight ice is probably the biggest risk factor. Since loss of
the static port will bugger up
3 basic flight instruments (altimeter, ASI and VSI) this is non-trivial.

Or masking tape left in place after maintenance. At least one airliner has
crashed because of this. Many fatalities.

--
Regards,

Stan

(running with scissors)
Date: 3/2/2004 5:18 PM Central Standard Time
Message-id:

"Gord Beaman" ) wrote in message
...
mah wrote:

Tarver Engineering wrote:


The sole reason for using a static port is so the guts can be removed
from
the pitot tube, in order to improve reliability. A pitot port produces
no
static pressure datum.


Just as an example, when the aircraft is sitting still on the ground -
airspeed = 0. Since the pitot and static ports are in the same state,
doesn't that imply that static pressure is present at the pitot port?

MAH

Sure it's there, but it's there only until the a/c starts to
move. It's then no longer 'static pressure' because it's been
raised by the ram effect of the movement.

That's why you now need a 'static port' to supply the static
pressure to use as a reference. Is it really that difficult to
see?!?


where are the mud bees?

Shacking up in the pitot tubes.

Dan, U.S. Air Force, retired

Can you point to a reg tht says that? I don't think it is true. Mine was
IFR certified when I bought it, and it did not have alternate static (I've
since added it). Also the FAA materials for the IFR written mention several
times that breaking the VSI glass is the way to get alternate static on an
airplane that doesn't have a valve. I wouldn't think they'd make such a big
deal about it if an alternate static source was requried for IFR cert.

The CO wrote:

IIRC in fact, for an aircraft to be certified for IFR it has to have an
alternate
static source *as well*.

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

"The CO" wrote in message =
...
=20
=20
Well the only tiny grain of truth in that statement is that a static
port can be occluded by a
foreign object. On the ground this can be something like an insect
setting up housekeeping
in it, in flight ice is probably the biggest risk factor. Since loss =
of
the static port will bugger up
3 basic flight instruments (altimeter, ASI and VSI) this is =
non-trivial.
=20
The CO
=20
=20
Well, let me tell you of the time my airplane was released from an =
annual
inspection with the static line open to the air in my pressurized cabin.
Since I'm cautious, I'd waited for MVFR conditions before launching.

My cabin began to pressurize just as I entered the base of the stratus,
and my rate of climb suddenly showed zero, among other annoying signs.
I continued my climb by maintaining attitude until I popped out on top,
and asked for an ILS approach and return for landing.
An airliner ahead of me called out the tops of the clouds, so I had
a pretty good idea of my altitude before intercepting the ILS.

If I hadn't been so close to the airport, I'd probably have thought =
about
dumping pressurization to see if the altimetry would come back,
but in this case it was easy just to return and let the mechanic
re-connect the hose. He was pretty embarrassed.
---JRC---

Ray Andraka wrote:

Also the FAA materials for the IFR written mention several
times that breaking the VSI glass is the way to get alternate static on an
airplane that doesn't have a valve. I wouldn't think they'd make such a big
deal about it if an alternate static source was requried for IFR cert.


It should be mentioned here that this trick only works on an
unpressurized a/c. You won't get much activity on the VSI needle
if you try this with a pressurized aircraft!.

--

-Gord.

Tarver Engineering release for service
From: Stan Gosnell
Date: 3/2/2004 5:26 PM Central Standard Time
Message-id:

"The CO" wrote in
:

Well the only tiny grain of truth in that statement is that a static
port can be occluded by a
foreign object. On the ground this can be something like an insect
setting up housekeeping
in it, in flight ice is probably the biggest risk factor. Since loss of
the static port will bugger up
3 basic flight instruments (altimeter, ASI and VSI) this is non-trivial.

Or masking tape left in place after maintenance. At least one airliner has
crashed because of this. Many fatalities.

--
Regards,

Stan


Masking tape should NEVER be used to wrap pitot tubes or cover static ports.

As far as leaving the tape on the maintainer is supposed to write it up, the
maintainer is supposed to remove the tape when he is done and document it, the
pilot is supposed to read the forms, the pilot is supposed to preflight the
aircraft which specifically includes checking the static ports etc.

Dan, U.S. Air Force, retired

"Ray Andraka" wrote in message
...
Can you point to a reg tht says that? I don't think it is true. Mine
was
IFR certified when I bought it, and it did not have alternate static
(I've
since added it). Also the FAA materials for the IFR written mention
several
times that breaking the VSI glass is the way to get alternate static
on an
airplane that doesn't have a valve.

That might work if the cabin was unpressurised, depends on whether the
guage face
was vented to the static side of the pressure balance.

I wouldn't think they'd make such a big
deal about it if an alternate static source was requried for IFR cert.

Ah, in Australia mate. I can't quote the ANO/R off the top of my head
but
to be certified for Class 1 it needs an alternate static source IIRC.
I'll see if
I can find the ANO/R somewhere.
(ANO= Air Navigation Order ANR= Air Navigation Regulation)

I can't speak for the FAA, so if they don't require alternate static
source for
Class 1 IFR I'm rather surprised, but I guess it could be the case, I
don't know.

Class 4 IFR (NVMC) doesn't require it in Oz.

The CO

(B2431) wrote:

Masking tape should NEVER be used to wrap pitot tubes or cover static ports.

As far as leaving the tape on the maintainer is supposed to write it up, the
maintainer is supposed to remove the tape when he is done and document it, the
pilot is supposed to read the forms, the pilot is supposed to preflight the
aircraft which specifically includes checking the static ports etc.

Dan, U.S. Air Force, retired

Y'know, I find it amazing to hear of where someone 'missed' a
taped over static port before a flight. In all of the multi
thousands of preflights that I've done I've NEVER done that,
never, nor heard of any of my compatriots doing it
either...amazing indeed.
--

-Gord.