Flying IFR in Older Aircraft

When is an airplane too old for the clag? Can retrofit glass bring new life or is the risk too high?


A reader recently questioned the wisdom of flying IFR in “old” aircraft with traditional flight displays that lack modern accouterments—GPS in particular. It’s a fair question and one that deserves some thought. I have to admit that growing up in an earlier age, and having flown IFR for almost a decade before I had the luxury of even a DME, and three decades before I experienced glass, I don’t feel deprived if I have to keep an E6B and a plotter handy to periodically check ground speed and ETAs. But there is more to it than this.

How Old Is Old?

When I took instrument training in 1973, the older training plane was a 1965 Cessna 172 with dual Narco NAV/COMs—hardly old by that day’s standard. Today, the C-182T that I often fly is a 2007 model with the G1000/GFC 700 and an XM WX subscription. So it’s about the same relative age as what I trained in, but the capabilities are of course, strikingly different.

The non-glass aircraft that I have access to today include a C-172P and a U-206G both have a GX-55 GPS. For the most part, these allow me to keep the E6B and plotter stowed, but they are still round-dial airplanes that are more than a quarter-century old. While it can be assumed that as long as the aircraft continues to have an annual and the various avionics pass the simplistic accuracy checks, they should be safe to fly—but in IMC?

Of course the other aspect is that you can have an old airplane updated with a modern Primary Flight Display (PFD) such as an Aspen EFD1000. But the firewall forward may still be an aging infrastructure. Should the vacuum pump and alternator be replaced periodically to reduce risk?

While I have flown some basic aircraft in IMC over the years, I have tried to maintain an awareness of the relative risk factor. There is no doubt that I would accept more challenging weather having the ability to “see” the current NEXRAD and lightning strike areas with the G1000. But I had no hesitancy in departing San Antonio (KSAT) in my steam-gauge C-172 with my wife and young daughter in a 600-foot overcast flying towards better weather.

The ability to evaluate weather (which is what flying IFR is all about) is one of the key factors in determining the level of risk that you accept, mitigate or reject. Among the factors involved in the risk matrix is the equipment being flown. Flying into IMC in an “old” aircraft that lacks GPS and other high-tech amenities is a personal decision, but to state categorically that it is not to be done, would ground a high percentage of flights that can (and do) fly the system daily with as high a level of safety as Technically Advanced Aircraft (TAA).

Level Of Proficiency

Although the FARs define “currency” relative to being legal to fly IFR, all instrument pilots should realize that legal and proficient are two different worlds. Read the accident reports to understand that pilots in TAA are flying into the ground almost as often as those in traditional non-GPS aircraft.

The last NTSB report that I read indicated that although the number of accidents for the period reported was slightly less with glass (141 vs. 125), the fatality rate was significantly higher (23 vs. 39). One of the more tragic is the two pilots who had a combined total of 55,000 hours flying into a mountain at night in good weather in a G1000 equipped aircraft—total lack of locational awareness.

Then there was the Cirrus SR-22 pilot who neglected to turn on the pitot heat resulting in the Air Data Computer output providing the big red X on the pitot static instrument displays. His life saver was the ballistic chute.

One of the problems with analyzing statistics is the inability to categorize the large number of variables involved and the often small samples available.

The NTSB study included:

1) An analysis of accidents and activity data of airplanes with and without electronic PFDs, to measure differences in activity, accident rates, and accident circumstances.

2) A review of training resources and requirements related to glass cockpit displays to characterize the training and identify areas for potential safety improvement.

3) A review of accidents to identify safety issues associated with the introduction of glass cockpit displays.

Problems of Glass Safety

While our reader emphasized the safety benefits of glass, they come with some liabilities. The lack of standardization of glass displays makes it awkward for pilots to move between the G1000 and Aspen for example. Although the layout of data is often intuitive that is not always the case—vertical speed readout for example. As more glass becomes available on the rental market this may be a major problem for FBOs.

The wide differences of operating the plethora of screens to obtain the desired information has resulted in the “head-in-the-cockpit” syndrome. This can lead to information overload.

Thus the pilot requires a fairly intimate familiarity with the various push, pull and twists to acquire the desired information in a reasonable time.

This leads us to the training problem. It has been shown that pilots who move from the traditional six pack to glass make the transition to proficiency quicker than the reverse. This may be because the scan acquired with the old layout required more discipline. Why? The chances are these “older” pilots did not have an autopilot they could call on when things got busy and they had to spend more time and talent developing and maintaining the aviate scan.

There may be a tendency for some pilots to over-extend themselves believing that the autopilot and the GPS moving map will supplement their lack of skill. Computers can perform many tasks quickly, but when not programmed correctly they do the wrong thing quickly as well. Unravelling a programming error while flying is not fun and can be outright dangerous.

With glass, there is a larger time-slice required to work and assimilate the information available. Often this information is superfluous (nice-to-know) rather than essential. The NTSB noted that pilots of glass are not always provided all the information necessary to adequately understand unique operational and functional details of PFDs. Overall, the study did not show a significant improvement in safety for TAA.

Other than ensuring that the alternator belt is not frayed there is little a pilot (especially a renter) can do to have some assurance that a 20 to 40 year-old airplane can be safely flown in IMC. Likewise, the TAA pilot needs to understand that despite all the glitter, there are serious considerations to flying with all the bells and whistles.

What Needs To Be Done?

If you fly an older aircraft with just the basic flight and navigation systems ensure that your scan is brought to a high level of proficiency. Periodic recurrent training (an IPC) should be a prerequisite for any pilot who flies in IMC—regardless of the age of the aircraft. Certainly a portable GPS or tablet is a consideration along with a hand held NAV/COM. But the study did not show these devices measurably decreased the accident rate.

Several accidents highlighted the complexity and unique functionality of glass cockpit displays. Pilots must be prepared to identify and safely respond to system malfunctions and failures. As aircraft become more complex, demands placed on pilots to manage and monitor equipment continue to increase.

In contrast to generalized training required to operate relatively simple systems in older aircraft, glass cockpits (that rival the complexity of transport category aircraft), need advanced training and periodic recurrency in their use.

The glass revolution came upon general aviation rather quickly and the major players moved to provide displays and functions that were innovative. But having subtle differences between the various vendors is troubling as pilots move from one cockpit to the next. Placement, color coding and functionality are but a few of the obvious standards that need to be addressed.

There may not be any possibility of a rational restructuring with respect to the knobs and buttons but that would be helpful as well. Datalinks, vast storage and flat panel software defined buttons provide unbelievable possibilities for information retrieval and display. The industry would be well served by an effort to provide standardization.

What Can We Conclude?

Certainly pilots must ensure that whatever they are flying has been properly maintained. Older aircraft are more likely to experience maintenance and in-flight problems than newer ones. Flying into heavy weather with just the basics is probably accepting a greater risk factor than may be prudent.

But, flying a TAA and not having your scan and skill levels at a high state of proficiency is likewise putting the flight in the high-risk category. Further, the knowledge required to find and use the various TAA functions is a formidable obstacle to using these safety features effectively.

The primary safety issues with IFR continues to be a lack of essential skills and procedural techniques that leads to fatal mistakes as frequently in steam-gauge as well as glass displays. Whatever you fly, make sure your training and proficiency will minimize the risk.

Ted Spitzmiller is a CFII, FAASTeam rep and the IFRR editor. He has an MS in Computing Information Systems.

This article originally appeared in the March 2014 issue of IFR Refresher magazine.

Read More from IFR Refresher, and learn how you can receive a FREE BOOK!