What’s Your Poison – Glass Cockpit or Round Dials?

Glass cockpits have been around for decades, replacing the original round dials, first in transport category aircraft and then filtering down to the smallest general aviation and experimental aircraft.

Are glass cockpits for everyone? Traditionalists will maintain that using round dials is essential to obtain and maintain the excellent stick and rudder skills real flying demands, but glass cockpits are now a fact of life. Some new pilots may never have flown with round instruments.

Has this advanced technology improved safety or the flying experience? I had one sales rep for a major avionics manufacturer, in a moment of unguarded candour, describe his company’s product as “just eye candy”.

But glass cockpits do have many advantages over round dials some of which are listed below:


  1. No parallax. The next time you are pre-flighting an airplane, try to read round dial instruments from the right seat. In glass cockpit equipped aircraft, the viewing angle still makes a right-seater’s job difficult, but there is no parallax.
  • Accuracy – With a glass cockpit, you are not interpreting altimeter or airspeed needle position, the numbers are displayed on the screen.
  • Graphical weather display – The ability to have near real time data linked weather displayed in the cockpit provides pilots with forecasts, radar reports, satellite imagery, pilot reports, and more.
Image of Graphic Weather Display
Graphic Weather Display
  • Traffic display – In congested airspace, traffic display will never replace keeping the pilot’s eyes outside the aircraft but it can be an invaluable aid.
  • Terrain awareness and synthetic vision – Plays an important role in increasing situational awareness.
  • Check Lists – You always have checklists at your fingertips no more searching the cockpit for the paper copy.
  • Airspace Mapping – It’s sometimes hard to judge where airspace boundaries start and end. Glass cockpits show position compared to airspace boundaries.
  • Eye Candy – They do look great and can give passengers a sense of confidence in the aircraft.
  • Reliability – With fewer parts, no spinning gyros, etc. there is less to go wrong.
  • Bluetooth Syncing – The ability to transfer flight plans from an IPad directly to the avionics system.

It is a truism, however that no aircraft is ever safer than the pilot flying, and the accident data does not show glass cockpits to be inherently safer than round dials.

As the biggest impediment to the adoption of glass cockpits is cost, if you are looking for improved flying safety it may be better to invest in your personal flying skills and hours flown than in more technology.

The pros and cons of glass are a great debate to have. The technology is constantly evolving but it will be many years, if ever that glass becomes a must for every pilot or mission.

ADS-B What is all the talk about diversity?

Unlike the FAA in the United States, which over the last two decades invested in ADS-B ground stations to cover the majority of their landmass. Nav Canada invested in Aireon, a space-based ADS-B solution to cope with our vast and sometimes inaccessible geography.

Space-based ADS-B
Space-based ADS-B

This has resulted in most of the general aviation fleet having their transponder antennas on the wrong side of the aircraft, bottom verse top. So, do we just need to relocate the antenna?

It’s not that simple for several reasons. ADS-B ground stations are still located at many Canadian airports, requiring the bottom antenna to be retained. For anyone flying into US airspace only having a top-mounted antenna would not work with a ground-based system. To deal with these issues, transponders need to be diversity models.

Diversity in ADS-B

Diversity in ADS-B refers to having two antennae connected to a single transponder.

The way a single transponder system is connected to two antenna functions is through a technique called Diversity. Each antenna is connected to a dedicated receiver in the transponder. When the system is interrogated, the signal strength measured in each receiver is compared to the other and the one with the strongest signal directs the single transmitter to reply through its antenna only. The requirement for two separate receivers and the comparator circuitry is what increases the cost of diversity transponders by several thousand dollars.

ADS-B transponders are also mandated to continually broadcast the aircraft position and information regardless of interrogation. Diversity transponders alternate their broadcast between the two antennas the Aireon satellite system does not interrogate; it relies on this unsolicited ADS-B Out broadcast.

When can we expect implementation?

Unlike the United States all-or-nothing ADS-B Out equipage deadline on January 1, 2020, Nav Canada is planning a phased implementation. As to when – due to pressure from pilots and operators about the cost of diversity, Nav Canada has delayed implementation and is working with Transport Canada to finalize mandates. Stay tuned for updates.