Moving from round dials to a glass cockpit

What actually changes on a glass panel

The six instruments are all still there, redrawn on the primary flight display (PFD) in roughly the same basic T. For a part-by-part tour of one common panel, see how to read the G1000 PFD.

• Attitude fills the whole screen, horizon to horizon, instead of a small dial in the middle of the panel.
• Airspeed is a moving tape on the left, with the coloured arcs turned into bands.
• Altitude is a tape on the right, with vertical speed beside it and the selected altitude above.
• Heading becomes a horizontal situation indicator (HSI) at the bottom: a compass rose with the course needle laid over it.
• The turn coordinator splits in two: a turn-rate arc on top of the HSI, and a small slip/skid bar under the roll pointer.

Tapes and trend vectors

A tape gives you an exact number but loses the shape a needle gives you. To put back the sense of movement, the PFD draws trend vectors: magenta lines on the speed and altitude tapes, and the arc on the HSI, whose tips show where the value will be in about six seconds (six on this site’s panel). On the HSI there are marks for half rate and rate one, so a rate-one turn puts the arc tip on the 18° mark.

Behind the screens

Three units feed the PFD. The AHRS (attitude and heading reference system) replaces the spinning gyros with solid-state sensors. A magnetometer keeps its heading aligned with magnetic north, so there is no heading indicator to reset. The air data computer (ADC) turns pitot and static pressure into airspeed, altitude and vertical speed. It still reads the same pitot tube and static port, so a blockage fools glass exactly as it fools round dials.

The multi-function display

Beside the PFD, the multi-function display (MFD) carries the moving map with your flight plan, and a strip of engine and fuel information that used to be a row of small gauges. The map is a picture of where the GPS thinks you are. It is not a flight instrument.

The challenges pilots meet in the first few hours

Numbers instead of needle positions

On round dials you read speed and height from where a needle points, often without reading the number. On tapes the numbers roll past and it takes a while to see a trend in them. Pilots new to glass tend to chase digits, correcting a 20 ft error by staring at the altitude box. The trend vectors are the cure: they show the change before the number has moved much.

Fixation and heads-down time

Everything is on two screens, so it is easy to look at one tape, or the map, for too long while a heading drift builds on the HSI. In visual flight the pull is to look in, not out.

Knobs, softkeys and menu-diving

The buttons along the bottom of each display change meaning from page to page, and the same knob can set a frequency, a course or a waypoint. Hunting for a page in a busy moment is the new version of fumbling for a chart. Our G1000 basics guide covers the softkeys, page groups and FMS knob.

Autopilot mode confusion

A glass panel usually comes with an autopilot that shows its modes in a strip across the top of the PFD: armed modes in white, active in green. The classic trap is assuming it is doing what you meant rather than what you selected, or missing a mode that changed by itself, such as an altitude capture or a reversion to pitch hold after a failure.

Leaning on the map and the automation

The magenta line is very easy to follow. Pilots who always follow it, with the autopilot engaged, lose the habit of knowing where they are without it.

Trusting the screens without cross-checking

Crisp graphics look authoritative. A frozen or wrong display can look just as crisp, so keep checking the PFD against the standby instruments and against what the aircraft is doing.

How to build confidence

Start with a structured conversion with an instructor. In the UK and EASA countries this is formal: an electronic flight instrument system (EFIS) is one of the differences within the single-engine piston class, so you need differences training from an instructor, who signs your logbook. It does not expire. In the UK the entry names the particular system, and can be marked “VMC only” if you do not hold an instrument or IMC rating; you then need more training before flying it under IFR. The CAA also advises further differences training when you move to a different EFIS system. In the US there is no separate endorsement, but schools, clubs and insurers usually want a checkout. A sensible order:

1. Learn the system on the ground first: the pilot’s guide, a desktop trainer, and the aircraft with the master on, until you can find each piece of the six-pack without searching.
2. Chair-fly each phase of flight: which knob sets the heading, where the frequency goes, which button arms the approach.
3. Add one function at a time. Hand-fly first, then navigation on the HSI, then the autopilot.
4. Practise the failures with your instructor: each screen, each sensor, and limited panel on the standby instruments.

Then build the habits that keep you ahead of the automation:

• Brief the modes before each phase: which lateral and vertical mode, what is armed, and the altitude it will level at.
• Say every mode change aloud as it appears on the annunciator strip, whether you pressed the button or it changed by itself.
• Ask “what is it doing now, and what will it do next?” If you cannot answer, drop a level of automation and hand-fly until you can.

How to practise on this site

This site is a free trainer in your browser. It is not an approved training device and does not count towards logged training, but it is a cheap place to learn where to look and which buttons do what before you pay for an aircraft. The instrument rating course can be flown in a glass cockpit or a round-dial one.

Try it: Fly “Straight and level, climbs, descents and rate-one turns” on the glass panel

That lesson is hand-flown with the autopilot off: a 500 fpm climb from 3000 to 4000 ft, a level-off, a descent back and rate-one turns. Then fly the same lesson on round dials and notice where your eyes go on each. After that, try “Attitude indicator failed: limited panel” on glass, which fails the AHRS so you fly on the standby attitude indicator with the speed and altitude tapes still working, and “ILS from radar vectors, 8 NM final” to manage the course source and autopilot modes on an approach. The ILS guide explains the needles.

Free play lets you set up your own flight with the failures you choose: pitot, static or vacuum in either cockpit, plus the AHRS and air data computer on glass. On the glass panel, the Failures tab can also blank the PFD or the MFD so you see reversionary mode.

To learn the panel itself, button by button, use the glass cockpit trainer for the Garmin G1000, set up as a Cessna 172S, with an instructor who rings the control to press and talks you through power-up, the softkeys, the menus and the page groups, then the radios, flight plans, the autopilot and failures.

Try it: “Power up and find your way around the controls” in the glass cockpit trainer

What you gain

• Situational awareness. The moving map shows your position against the route, airspace and terrain at a glance.
• Trend information. Speed, altitude and turn trends show where you are heading, not just where you are.
• Integrated navigation. GPS, VOR and localiser all show on the HSI, with the source named, and the flight plan is on the map.
• Alerts in words. Cautions and warnings appear as messages, such as LOW VACUUM, rather than a gauge you have to notice.
• Reliability. Solid-state sensors have no spinning parts, and the main attitude display no longer depends on a vacuum pump that can fail slowly and silently.

The NTSB’s 2010 study showed that these gains do not arrive by themselves: they come with equipment-specific training.

The pitfalls: failures, complacency and going back

New kinds of failure

On round dials one failure usually takes out one or two dials. On glass you lose whole units. An AHRS failure puts red crosses over attitude and heading and disconnects an autopilot that depends on it. An air data computer failure crosses out the speed, altitude and vertical speed tapes, and autopilot modes that need air data drop out. If a display fails, the other one reverts to a combined layout.

The standby instruments are your way out: on this site’s panel an attitude indicator, an airspeed indicator and an altimeter. Its standby attitude indicator is vacuum-driven, as in some earlier glass trainers; many newer aircraft use an electric one with its own battery. The standby airspeed indicator and altimeter share the pitot and static ports with the air data computer, so a blocked port affects them too.

Automation complacency and skill decay

An autopilot that flies well makes it easy to stop flying. Hand-flying skills fade quietly, and the day you need them is usually the day something has already failed. Hand-fly some of every flight, including an approach now and then.

Going back to round dials

The gaps are no trend vectors, a heading indicator that drifts and has to be reset to the compass, and no map. Slow the scan down, give the needles time to settle, and plan your navigation the old way. The VOR guide is a good refresher.