Aviation technology has experienced massive breakthroughs in the last century since the Wright Brothers first flew in Kitty Hawk. Airframe and propulsion technology have progressed manned flight capabilities from flying two feet off the ground for a few hundred feet to flying faster than the speed of sound tens of thousands of feet in the air.
But one of the most significant aviation breakthroughs just in the last few decades is avionics technology. Specifically, the transition from traditional “steam gauges” (more on why they are called that in a minute) to glass panel cockpits that integrate traditional instruments into dynamic displays.
As the prevalence of glass cockpits continues to increase, student and seasoned pilots alike now have the chance to decide if they want to fly using traditional instruments or modern glass avionics. So one of the great debates in aviation right now is this: steam gauges vs. glass cockpits: which is better?
Aviation technology as a whole is moving towards glass avionics, which are more expensive but less prone to mechanical errors and provide more redundancy and integrated systems information than traditional steam gauges. However, both technologies are still widely common today and safe to use.
For many pilots it isn’t as simple as selecting which type of avionics technology is better, because different pilots in different situations will have different preferences, experiences, and budgets. To better diagnose which route is “better” for you, let’s rank each using seven different grading factors.
Steam Gauges vs. Glass Cockpit: 7 Factors Compared
I have trained in and owned several different airplanes over the years with both types of avionics and each of them come with pros and cons. About a third of my time is on glass panels and the rest either on steam gauge or partial glass panels. You’ll have to decide which path is ultimately better for you, and that path might change over the years as you have different needs, budget, and preferences.
Here are the seven different factors between steam gauges and glass avionics I’ve come to notice after many hours flying both:
Factor #1: Training
For a student or newly minted private pilot, in a single engine, non-complex aircraft (Cessna and Piper) he or she might find it easier to interpret “steam” gauges at a glance more efficiently than searching for information on the glass display.
The important element of this in training is to understand the ‘basics’ of what keeps the airplane stable in controlled flight. It is pitch and airspeed, and it is easy to grab at a glance in a steam gauge cockpit.
In my experience, I prefer some of the steam gauges in my Cessna 182 because the needle nature of the visual representation gives me a better feel for the trend of the flight characteristics.
For example, if the nose is pitched up and the wings have a high angle of attack (not level with the horizon) I can feel and see the impact on airspeed because I can see the needle moving the direction toward lower numbers and zero. Furthermore, I can see that the VSI (vertical speed indicator) isn’t straight and level on a “0” indication.
In a glass cockpit, the airspeed is represented as a ‘tape’ with the tape changing numbers on a small field without the benefit of seeing zero on the tape until you are at zero! The same is true for the VSI. At level flight, the steam gauge needle is horizontal. If there is even the slightest climb or decent, the needle will trend down or up depending on the direction of the airplane relative to the horizon.
On a glass display, the numbers will simply increase or decrease, which is fine, it’s just different. You just have to take an extra step to interpret what the numbers are telling you. I think it is better to have a “glass display” in much faster more complex aircraft flying complex instrument approaches and higher altitude flights, but in many cases, my preference is to have steam gauges in less complicated aircraft. I am comfortable with either platform but have my preferences depending on what I am flying and where. More on that below.
Factor #2: Transitioning Between Steam Gauges and Glass
The easiest way to explain the reality of transitioning from steam to glass is in one story. A very good friend of mine who is a very accomplished instrument rated pilot, owns and has owned several airplanes including a turboprop, recently told me that he had taken his primary training in a glass cockpit that he purchased, but when he pursued his next rating using the flight school airplane he had to do so in a steam gauge airplane and it was quite the challenge.
He was a little more colorful in his full description of the experience. It helped that it was a two week course so he had the total immersion process taking place, but he told me he wished he had learned on steam gauges then transitioned to glass later.
Glass avionics are able to display so much integrated information, including systems, navigation, and flight planning, that you can very quickly get spoiled with their features. When having to move back to steam gauges some pilots can be lost (figuratively and literally) without the technological help of the newer avionics.
Personally, I learned steam gauges and the jump into glass was much easier because it removed so many other steps and processes I otherwise had to do manually on steam gauges. Going from glass to steam would have been much harder.
Factor #3: Reliability
There is no doubt that glass cockpits, generally, are more reliable simply because their power source is a battery only and there is not the reliance on vacuum pumps and analog technology. However, glass cockpits do fail, sometimes a piece at a time.
I had a Cessna 182 with a G1000 glass cockpit and my wife and I were flying in instrument conditions at 8,000 feet. With NO notice, bells and whistles started ringing and the oil pressure was flashing with a big fat “0” showing for oil pressure. We declared an emergency with Houston Center and flew a circling approach into a most convenient uncontrolled airport within an easy glide of our location.
The problem? A failed wiring harness that needed to be replaced.
A little paperwork with the FAA, a couple days at a repair station and we were on our way. So much for the advantage of glass.
Glass doesn’t mean no problems. However, there is one major advantage to most glass software applications; the system monitors itself for system errors.
If a component is trending to a failure it will give you an indication with an error message. This is very helpful in an environment when relying completely on instruments.
For example, in a steam gauge environment, the vacuum pump (which drives/turns the gyros necessary for coordinated flight) can begin to slow down without giving you any notice, resulting in an attitude indicator that will begin to fail, without telling you, and showing the airplane in a turn as it loses its ability to display correct information.
If the pilot doesn’t catch this and tries to adjust to incorrect information he / she could be chasing incorrect information and fly the airplane into the ground. The pilot is required to ‘trend monitor’ to confirm with other instruments whether there is an actual problem or not. Until glass gauges, that was the way every airliner and every aircraft in the world flew. Today’s glass panel has some advantages.
Factor #4: Cost
With few exceptions, glass avionics simply cost more than steam gauges. Whether you are purchasing an airplane, upgrading an existing one, or even renting, the price of the panel will manifest itself in the overall costs of flying that airplane.
The cost of conversions from steam to glass cockpits can be from reasonable to staggering. Many private aircraft owners are combining steam and glass gauges to get the best of both.
Flight schools are buying new airplanes coming from the factory with glass panels and students are having to pay the higher rental rates per hour as a result of the increased expense for the flight school.
Luckily, the overall price of glass avionics is coming down with each passing year as it becomes more and more common. Garmin, Aspen, and others are releasing pretty powerful partial glass panel solutions that are very feature rich relative to their cost.
There are other reasons to upgrade some of the panel in a private airplane. The upgrade may include integrating new navigation and communication radios as well as engine monitory dynamics. Admittedly, once you start some of the upgrade, if resources are available, it is hard to stop the upgrades!
Alternatively, the used aircraft market has more and more airplanes that are already equipped with full or partial glass avionics. It might be cheaper to buy an airplane that was recently upgraded rather than paying for the upgrades yourself.
Factor #5: Situational Awareness
Probably the biggest reason to choose glass over steam is the Situational Awareness (SA). When things get busy in the cockpit, with weather, navigation or communication or other distractions, a quick glance can tell you the airplane is where it is supposed to be.
A glass cockpit will give the pilot a moving map with the airplanes location, including an HSI overlay (horizontal situation indicator), which is teeming with information for the pilot, including synthetic vision showing where the runway is, weather, traffic nearby, and much more. Once you get used to it, particularly in a very fast airplane, you will come to very much rely on it.
Conversely, steam gauges present this information to you separately, and so situational awareness can be much more difficult. Reading the CDI on your VOR (article: CDI, HSI, OBS, and Heading Indicator Explained) in order to visualize where you are on an approach can be MUCH more difficult than just seeing it on the large GPS of your glass display.
It’s worth noting that there are some very affordable solutions to improve your situational awareness even in an aircraft equipped with only steam gauges. While my 182 does have an Aspen 1000 and a Garmin 430W that provide me with decent situational awareness, my favorite tool by far is using Foreflight on my iPad, coupled with my Sentry (link to read reviews on Amazon – I LOVE this thing) that will also provide weather and traffic information within Foreflight.
It will overlay approach charts to scale on top of moving maps, and show you exactly where you are at all times. Compared to actually upgrading the onboard avionics of the aircraft, this setup is VERY affordable. But most importantly it can give you a massive leap in situational awareness compared to just steam gauges alone.
Factor #6: Cockpit Resource Management
There is no question that data supports the improved safety of a two-person crew over single pilot operations and it is called Crew Resource Management (CRM).
The nod goes to glass with its capabilities to serve in a co-pilot role using the autopilot and giving immediate access to key flight information such as weather along the route of flight, instrument approach plates and information, frequencies for everyone you will need to talk with, checklists, flight progression while managing step down altitudes, etc.
This amount of information is not only helpful in a single pilot cockpit, but especially a two-pilot cockpit. Glass displays such as the Garmin 3000 are fully customizable in what each pilot needs to see on their screen in additional to primary flight display (PFD) information, whether that be traffic, weather, approach charts, aircraft systems, or more. With this kind of technology, it is even easier for a crew to better split up duties and focus areas within a flight. Steam gauges are inherently less dynamic.
Factor #7: Nostalgia
All of the bells and whistles of glass panels aside, some of us simply like steam gauges (either as a whole panel or at least part of one) for the nostalgia alone. Whether it’s a preference in how the instrument actually displays information, the cost to buy or fix it, or the history of it, sometimes you just can’t beat the old technology.
I become more sentimental about outdated technologies when I realize where they came from, or why they were a huge technological advancement at the time. The cockpit we know today is very different from what used to be.
Here’s a very abbreviated edition of some of the major advancements that happened over the years. It might give you a new appreciation for an instrument still in your airplane that you see as outdated.
In the ‘early’ days, the cockpit instrumentation consisted of critical measurements of oil pressure and oil temperature, engine RPM and at a later time, airspeed. By WWII there were additional gauges in the cockpit including radio receivers, compass and gyros and roll, pitch and rudder information to help maintain controlled flight.
By the 1970’s advances in weather detection (sferics: lightening detection) entered the cockpit. The radios for communication and navigation (area navigation RNAV) improved in quality and reliability. Advances were made in aircraft performance and airplane sales of general aviation airplanes was solid year over year, and pilots were trained to AVIATE, NAVIGATE AND COMMUNICATE.
Training was focused on the flight characteristics of the airplane, without using an autopilot or “wing leveler”, the precursor to the 2 and 3-axis autopilot. All training was conducted by hand flying the airplane from takeoff to touchdown.
Not as much discussion these days on hand flying characteristics over coffee in FBO’s and hangars of America. Today the discussion is about the latest data upload and whether it was done directly from the cockpit or from the pilots living room.
A lot has changed but I hope the love for and the desire for the next flight isn’t being lost in the pursuit of more technology. There’s something special about flying an airplane that is decades or more older, using the same or similar equipment to what they would have used in that era.
It’s cool to fly fast, sleek, technologically advanced aircraft around, but I hope we’ll never lose to aviator’s dream of taking off in the early morning in a slow single engine tail dragger from a damp freshly mowed grass runway, with the window open and cruising in stable air at 80 mph over the countryside waving to neighbors. My, oh my, now that is flying.
Conclusion
Whether you are deciding what kind of airplane to train in for the first time, rent, upgrade, or purchase, avionics technologies definitely have their pros and cons. As with most decisions in aviation, I believe it comes down to what your average mission is going to be. Deciding which avionics package is right for you is a combined decision of the average requirements, budget, and context of your typical flight. Regardless of what avionics you have, never ever forget that your first responsibility is to fly the airplane.
Blue skies!
