Alternate static on "big iron"?

Last night 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 and
not removed. As you might imagine, the airspeed indicator and altimeter gave
erroneous readings and fed the onboard computers erroneous data; after a
series of bizarre warning messages (zero airspeed and "over speed warning"
from the computer) the pilots attempted to correct for contradictory
information and multiple warnings and the plane crashed into the ocean

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

Marc

Marc Lattoni wrote:

Last night 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 and
not removed. As you might imagine, the airspeed indicator and altimeter gave
erroneous readings and fed the onboard computers erroneous data; after a
series of bizarre warning messages (zero airspeed and "over speed warning"
from the computer) the pilots attempted to correct for contradictory
information and multiple warnings and the plane crashed into the ocean

I do not know the answer to your question, but an important point about
this crash is that the aircraft was completely flyable and should never
have gone down.

What caused the aircraft to crash was the fact that both pilots were so
distracted attempting to troubleshoot the problem that neither paid any
attention to flying the aircraft. I couldn't tell from your synopsis if
you were aware that the availability of alternate air was most likely
irrelevant to the outcome of this unfortunate accident.

--
Peter

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

"Marc Lattoni" wrote in message
news:c3%hc.1386$2q2.192@edtnps84...
Last night 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
and
not removed. As you might imagine, the airspeed indicator and altimeter
gave
erroneous readings and fed the onboard computers erroneous data; after a
series of bizarre warning messages (zero airspeed and "over speed warning"
from the computer) the pilots attempted to correct for contradictory
information and multiple warnings and the plane crashed into the ocean

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

Marc

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

The pitot tube was NOT taped over, only the static ports. The runway at
Puerta Plata is fairly level, not much slope. Would the airspeed operate
normally until the altitude changed, which would be after rotation?

D.

"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.

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?

ASI works just fine on takeoff is the static ports are blocked.

Hilton

Woops, I had pitot on my mind!

"Capt.Doug" wrote in message
news
"Brad Z" wrote in message Why did they even take off? Isn't airspeed a
required call-out and part of the operating rules for all carriers?

The pitot tube was NOT taped over, only the static ports. The runway at
Puerta Plata is fairly level, not much slope. Would the airspeed operate
normally until the altitude changed, which would be after rotation?

D.

On the B727, the Captain's or F/O's static sources are selectable from
Normal to "Alternate", which would provide the static instruments with
static air which is used for the Mach Airspeed Warning and Pressurization
systems

"Marc Lattoni" wrote in message
news:c3%hc.1386$2q2.192@edtnps84...
Last night 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
and
not removed. As you might imagine, the airspeed indicator and altimeter
gave
erroneous readings and fed the onboard computers erroneous data; after a
series of bizarre warning messages (zero airspeed and "over speed warning"
from the computer) the pilots attempted to correct for contradictory
information and multiple warnings and the plane crashed into the ocean

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

Marc

Marc,
The Canadair Regional Jet has a three static sources. They are
selectable from normal to alternate. This usually cross connects the
Captains to the F/O and vice versa. The third one is independent for the
Mach speed transducer and the Cabin Pressure Acquisition module.
It would be safe to assume that if one or more of the static port was
taped over for painting then all of them were taped over.
Our Turbo Props do not have a selectable static source. They do have
selectable Air Data computers though.
Michelle

Marc Lattoni wrote:

Last night 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 and
not removed. As you might imagine, the airspeed indicator and altimeter gave
erroneous readings and fed the onboard computers erroneous data; after a
series of bizarre warning messages (zero airspeed and "over speed warning"
from the computer) the pilots attempted to correct for contradictory
information and multiple warnings and the plane crashed into the ocean

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

Marc





--

Michelle P ATP-ASEL, CP-AMEL, and AMT-A&P

"Elisabeth" a Maule M-7-235B (no two are alike)

Volunteer Pilot, Angel Flight Mid-Atlantic

Volunteer Builder, Habitat for Humanity

"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?


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.