Urges Caution Following Reports Of Incorrect Readings
Avionics manufacturer and OEM supplier Avidyne Corporation has
issued an urgent 'Safety Alert' following reports of incorrect
altitude and airspeed information being displayed on some Entegra
EXP5000 Primary Flight Displays (PFDs) manufactured or serviced in
the past seven months.
"Avidyne has received a limited number of field reports of PFDs
displaying incorrect altitude and airspeed information," the
manufacturer states. "None of these occurrences led to an accident
or incident."
The company says these occurrences included incorrect display of
information at system startup, including one or more of the
following:
-
Altitude significantly
in error when compared to field elevation with local barometric
correction setting entered on PFD.
- Altitude significantly in error when compared to backup
altimeter with identical barometric correction settings on
both.
- Non-zero airspeed (inconsistent with high winds or propwash
from a nearby airplane) indicated at system startup.
- Altitude or airspeed indications that vary noticeably after
startup under static conditions.
- Erroneous airspeed indications in combination with erroneous
attitude indications.
- A steady or intermittent "red X" in place of the airspeed
indicator, altimeter, VSI or attitude indicator.
Avidyne stresses aircraft exhibiting any of these incorrect
indications should not be flown -- even if the indication only
appears on startup, and later returns to normal. In such cases,
"...the PFD should nonetheless be considered unreliable and the
aircraft should not be flown," the company states.
The manufacturer also reiterates the need for pilots to be
vigilant in conducting proper preflight and inflight checks of
instrument accuracy -- including preflight checks of the accuracy
of both the primary and backup altimeter against known airfield
elevation and against each other, and verification of airspeed and
other instrument indications against backup instrumentation, and
real-world conditions, while inflight.
Should pilots encounter suspect PFD information while inflight,
Avidyne urges pilots to contact ATC for assistance on determining
correct altitude, attitude and airspeed -- while also keeping in
mind the limitations of that information. Pilots who experience
incorrect PFD readings are also urged to discontinue the flight at
the earliest, safest opportunity to do so, and to stay out of
instrument flight conditions.
"Avidyne has notified the FAA and its OEMs about these events,
and Avidyne’s technical investigation is ongoing," the
manufacturer states. "At this time, this issue is considered to
affect all Avidyne Primary Flight Displays manufactured or serviced
between July 27, 2007, and February 1, 2008."
The final list of affected PFDs may differ based on the results
of Avidyne's investigation. Stay tuned.
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