Alternate static on "big iron"?

"Capt.Doug" wrote in message ...
"Marc Lattoni" wrote in message Do modern airliners not have an
alternate static source as on my 172?

The MD-80 does have an alternate static source for each side. It is a
checklist item. However, the crew was distracted at a busy time. Switching
to alternate static probably wouldn't come to mind very quickly.

D.

Where is the alternate static port vented? It can't be vented to the
cockpit in a pressurized aircraft, no?

"C J Campbell" wrote in message
...
Modern airliners have multiple static ports, but they do not have one like
your 172. The alternate static port in your 172 uses cabin air. Airliners
are pressurized, so an alternate static port like on the 172 would be
worthless.

I wonder. After all, the time you'd really need the alternate static port,
you'd be low enough for the cabin to be left unpressurized. More than
likely, the pilots would notice the need for alternate static reference
before they climbed above an altitude where pressurization is required.

I can believe that pressurized transport category airplanes don't bother
with a cabin-vented alternate static port, as a matter of the designers not
bothering to provide that. But I don't see any reason why that wouldn't be
a feasible safety feature.

Just select the cabin-vented alternate static port, and allow the cabin to
climb to ambient pressure altitude.

Pete

"Marc Lattoni" wrote in message news:c3%hc.1386$2q2.192@edtnps84...


Do modern airliners not have an alternate static source as on my 172?


They have alternate static, but it's not as simple as the one on
your 172. If yours is like most spamcan alternate static sources, it
opens the static system to the cabin air. Simple and almost
foolproof, but that sort of system wouldn't work on a pressurized
airplane. The artificially high cabin pressure would generate
erroneous readings. A pressurized airplane would have to have its
alternate static source open to the outside air (where it can be taped
over).

John Galban=====N4BQ (PA28-180)

On Fri, 23 Apr 2004 at 02:55:09 in message
hA%hc.5284$0u6.1143009@attbi_s03, Brad Z wrote:

Why did they even take off? Isn't airspeed a required call-out and part of
the operating rules for all carriers?

Because the airspeed read almost normal until they started to climb I
believe.
--
David CL Francis

"Andrew Sarangan" wrote in message Where is the alternate static port
vented? It can't be vented to the cockpit in a pressurized aircraft, no?

The alternate static port is inches away from the primary static port. Now
that you mention it, if one was taped over, the other would likely be taped
over also.
D.

on Discovery Channel there was a story of a Peruvian 757 that
went down because the two static ports had been taped over for cleaning

That and many other stories are recounted in a book (I got it as a gift) called
"The Black Box" and there appears to be a new edition out. Many of the stories
have transcripts of radio conversations, and there's background information on
the crews and circumstances as well as the information later gathered about the
incidents, many of which are unfortunately fatal crashes.

The events often seem to have been avoidable and in some cases you'll read it
shaking your head over the carelessness or lack of communication that clearly
led to poor decisions. I'd recommend it, though it's depressing reading and
you should never let your nonpilot friends read it!

http://www.amazon.com/exec/obidos/tg...-3567979-74566
41?v=glance