AFH Chapter 4-31 Human Factors

Human Factors

VMC to IMC

Unfortunately, accident reports indicate that continued VFR flight from visual meteorological conditions (VMC) into marginal VMC and IMC is a factor contributing to LOC I.

 

A loss of the natural horizon substantially increases the chances of encountering vertigo or spatial disorientation, which can lead to upset. 

 

IMC When operating in IMC, maintain awareness of conditions and use the fundamental instrument skills—cross-check, interpretation, and control—to prevent an upset.

 

Diversion of Attention

In addition to its direct impact, an inflight anomaly or malfunction can also lead to an upset if it diverts the pilot’s attention from basic airplane control responsibilities.

 

Failing to monitor the automated systems, over-reliance on those systems, or incomplete knowledge and experience with those systems can lead to an upset.

 

Diversion of attention can also occur simply from the pilot’s efforts to set avionics or navigation equipment while flying the airplane.

 

Task Saturation

The margin of safety is the difference between task requirements and pilot capabilities.

 

An upset and eventual LOC-I can occur whenever requirements exceed capabilities.

 

For example, an airplane upset event that requires rolling an airplane from a near-inverted to an upright attitude may demand piloting skills beyond those learned during primary training.

 

In another example, a fatigued pilot who inadvertently encounters IMC at night coupled with a vacuum pump failure, or a pilot fails to engage pitot heat while flying in IMC, could become disoriented and lose control of the airplane due to the demands of extended—and unpracticed—partial panel flight.

 

Additionally, unnecessary low-altitude flying and impromptu demonstrations for friends or others on the ground often lead pilots to exceed their capabilities, with fatal results.

 

Sensory Overload/Deprivation

A pilot’s ability to adequately correlate warnings, annunciations, instrument indications, and other cues from the airplane during an upset can be limited.

 

Pilots faced with upset situations can be rapidly confronted with multiple or simultaneous visual, auditory, and tactile warnings.

 

Conversely, sometimes expected warnings are not provided when they should be; this situation can distract a pilot as much as multiple warnings can.

 

The ability to separate time-critical information from distractions takes practice, experience and knowledge of the airplane and its systems.

 

Cross-checks are necessary not only to corroborate other information that has been presented, but also to determine if information might be missing or invalid.

 

For example, a stall warning system may fail and therefore not warn a pilot of close proximity to a stall, other cues must be used to avert a stall and possible LOC-I.

 

These cues include aerodynamic buffet, loss of roll authority, or inability to arrest a descent.