The rapid increase of cockpit automation and satellite navigation in General Aviation has been generally well received but is not without its critics. Much of the resistance to new technology has been a concern for lack of situational awareness and an overdependence on automation. Advanced cockpits such as the Garmin 1000 are not inherently problematic but become so when pilots fail to understand how such systems work, which is the focus of this article.
The Garmin 1000 (G1000) includes a multi-function (MFD) display with integrated moving map, like many of its competitors. One of the great features of the MFD is the ability to visually display holding patterns. But how does the system know where to put the hold and what size it should be? These are the types of questions we should be asking when learning to fly. The G1000 contains a database of navigational data, including the location, direction of turn and leg lengths of published hold. The database is designed to mirror paper navigational charts, including holding patterns and course reversals.
Holding patterns that are not in the database, unfortunately do not have the benefit of an MFD visualization. For patterns available in the database, the question remains; how does the system determine size and shape? First, the size of the pattern is determined by the groundspeed (and not airspeed) of the aircraft and recalculates continuously. Increasing the hold size as speed increases, and decreasing the size of the hold as speed decreases. This means that missing or inaccurate airspeed information has no bearing on the G1000’s ability to estimate the size of the hold. The shape of the hold is determined by groundspeed and wind conditions. Wind information is draw from the G1000, which compares ground speed and track to true airspeed and magnetic heading. In the event wind information is not available, the G1000 will assume no wind exists and draw the hold in a perfect racetrack shape, basing size solely on groundspeed.
One of the most common questions is whether or not a pilot should attempt to directly follow the MFD display or simply use it for situational awareness? The answer depends on whether or not the aircraft is equipped with a Flight Director and I will address that scenario first. The Flight Director (FD) places an indication on the attitude indicator directing the pilot to the roll and pitch required for that phase of flight, often referred to as a Flight Director Command. When the holding pattern is displayed on the MFD and a FD is in use, the best procedure is to select NAV mode on the FD and follow the commands on the attitude indicator. The G1000 FD commands the pilot to fly the hold as displayed on the MFD. Note that the FD holding commands will only be correct if the G1000 has accurate wind information.
In an aircraft without a FD, or when the FD is not providing the correct commands, holding patterns should be flow in the same fashion as a VOR hold. This includes flying inbound with the CDI and turning to the outbound heading at standard rate, as well as manually adjusting for outbound crosswind. There is a great temptation for pilots to visually follow the path on the MFD display, but this is not advisable. First, the position, speed and direction of the miniature aircraft on the MFD lags behind the actual aircraft, causing pilots to overshoot turns. Second, following the MFD may lead to fixation and distract the pilot form other critical functions such as communications, weather updates and fuel status. Finally, attempting to follow the MFD will result in substantial head motion and time looking away from the primary instruments. This runs a high risk of causing spatial disorientation and/or altitude deviation. Therefore, the holding pattern displayed on the MFD should only be cross-referenced for situational awareness and not as a primary navigation source.
While, the MFD does provide a great tool for situational awareness, some stages of flight may be better flow without attempting to use every automated feature possible. As planes continue to evolve, they will no doubt become even more automated and pilots will transition in to systems operators. But until then, pilots are just that – pilots, and they should fly the plane.
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