Home' RTCA Documents for Review : Addressing Human Factors/Pilot Interface Issues Contents 54
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located MW/MC within the primary field of view. When combined with the lack
of an aural, this type of annunciation design did not perform its intended function
of timely alerting for aircraft system state status.
Because of inadequate illumination, placards were not always visible. Although
there are regulatory and operational requirements for all placarded data to be in
clear view of the pilot, placards are often overlooked when designing flight deck
lighting. Also, lighting of placards is often overlooked when they are moved as a
result of a modification.
Instruments, displays, or controls were located outside the required field of view.
For example, some manufacturers and STC applicants have proposed placing
required engine instruments outside the pilot’s secondary field of view. The result
was the pilot’s scan to monitor and access information on the gauges led to higher
workloads and in some circumstances failure to notice anomalous engine or
powerplant performance indications.
Primary flight controls blocked PFD critical information. The control wheel
blocked critical information on the PFD during flight operations requiring
sustained roll inputs. For example, in some Multi-Engine Fixed-Wing aircraft, an
engine failure on takeoff required the pilot flying to put in a fair amount of rudder
and aileron to counter the rolling moment resulting from asymmetric thrust. This
sometimes resulted in a control wheel angle which blocked critical information
such as aircraft heading on the PFD.
Installing EFIS displays in a cockpit that had electro-mechanical primary
instruments has led to the display of primary information being located in a
different vertical or horizontal location than the original design. For example,
installing side by side electronic displays have resulted in the ADI moving
significantly outboard of the previous location. Pilot cross-checks were affected
by this type of placement. Additionally, some installations of electronic displays
in rotorcraft displace primary power instruments inboard to the center of the
instrument panel resulting in longer head-down pilot scans to monitor torque or
rotor speed during one-engine inoperative or autorotation operations.
Flight deck implementations with too much physical separation and visual scan
between existing instruments and new GPS status annunciations required constant
head movement while monitoring an LPV approach.
A standby flight display ADI used as a backup to mitigate the loss of a primary
flight display required significant pilot action to keep it displayed following loss
of normal power. A standby instrument’s intended function is to be used as a
backup attitude / air data reference during failure scenarios, when the flightcrew
has lost all normal display functions. Typically these are high workload conditions,
with degraded power sources and potentially adverse effects on manual flight path
Approved Design Examples
New equipment intended to be monitored frequently along with existing
equipment during high gain piloting tasks such as flight path control on final
approach, have been collocated close to each other and within the pilot’s primary
field of view to reduce pilot visual scan and ensure that indications and
annunciations are detectable.
Several options have been certified to comply with the requirement of no pilot
action required, such as the following:
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