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7. Reduce power to the entry power setting to maintain
the desired airspeed.
8. Re-trim the aircraft as soon as practical or continue
into a right hand steep turn and continue from step 3.
5-55
Figure 5-69. Unusual Attitude Recovery Protection. Note the brown horizon line is visible at the bottom.
9. Once the maneuver is complete, establish cruise flight
and accomplish all appropriate checklist items.
Unusual Attitude Recovery Protection
Unusual attitudes are some of the most hazardous situations
for a pilot to be in. Without proper recovery training
on instrument interpretation and aircraft control, a pilot
can quickly aggravate an abnormal flight attitude into a
potentially fatal accident.
Analog gauges require the pilot to scan between instruments
to deduce the aircraft attitude. Individually, these gauges
lack the necessary information needed for a successful
recovery.
EFDs have additional features to aid in recognition and
recovery from unusual flight attitudes. The PFD displays
all the flight instruments on one screen. Each instrument is
superimposed over a full-screen representation of the attitude
indicator. With this configuration, the pilot no longer needs
to transition from one instrument to another.
The new unusual attitude recovery protection allows the pilot
to be able to quickly determine the aircraft’s attitude and make
a safe, proper and prompt recovery. Situational awareness is
increased by the introduction of the large full-width artificial
horizon depicted on the PFD. This now allows for the attitude
indicator to be in view during all portions of the scan.
One problem with analog gauges is that the attitude indicator
displays a complete blue or brown segment when the pitch
attitude is increased toward 90° nose-up or nose-down.
With the EFDs, the attitude indicator is designed to retain a
portion of both sky and land representation at all times. This
improvement allows the pilot to always know the quickest
way to return to the horizon. Situational awareness is greatly
increased.
NOTE: The horizon line starts moving downward at
approximately 47° pitch up. From this point on, the brown
segment will remain visible to show the pilot the quickest
way to return to the level pitch attitude. [Figure 5-69]
NOTE: The horizon line starts moving upward at
approximately 27° pitch down. From this point on, the blue
segment will remain visible to show the pilot the quickest
way to return to the level pitch attitude. [Figure 5-70]
It is imperative to understand that the white line on the
attitude indicator is the horizon line. The break between the
blue and brown symbols is only a reference and should not
be thought of as the artificial horizon.
Another important advancement is the development of the
unusual attitude recovery protection that is built into the PFD
software and made capable by the AHRS. In the case of a nosehigh
unusual attitude, the unusual attitude recovery protection
displays red chevrons which point back to the horizon line.
5-56
Figure 5-70. Horizon line starts moving upward at 27°. Note that the blue sky remains visible at 17° nose-down.
These chevrons are positioned at 50° up on the attitude indicator.
The chevrons appear when the aircraft approaches a nose-high
attitude of 30°. The software automatically de-clutters the PFD
leaving only airspeed, heading, attitude, altimeter, VSI tape,
and the trend vectors. The de-cluttered information reappears
when the pitch attitude falls below 25°.
For nose-low unusual attitudes, the chevrons are displayed
when the pitch exceeds 15° nose-down. If the pitch continues
to decrease, the unusual attitude recovery protection declutters
the screen at 20° nose-down. The de-cluttered
information reappears when the pitch increases above 15°.
Additionally, there are bank limits that trigger the unusual
attitude protection. If the aircraft’s bank increases beyond
60°, a continuation of the roll index occurs to indicate the
shortest direction to roll the wings back to level. At 65°, the
PFD de-clutters. All information reappears when the bank
decreases below 60°.
In Figure 5-71, the aircraft has rolled past 60°. Observe the
white line that continues from the end of the bank index.
This line appears to indicate the shortest distance back to
wings level.
When experiencing a failure of the AHRS unit, all unusual
attitude protection is lost. The failure of the AHRS results
in the loss of all heading and attitude indications on the PFD.
In addition, all modes of the autopilot, except for roll and
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Instrument Flying Handbook仪表飞行手册上(113)
