Friday, May 10, 2013

Opinion: Learning to Fly with Glass vs. 6-Pack?

INTRODUCTION AND CAVEATS

I confess up front that I find the arguments that the 6 pack is a better learning vehicle than glass to be questionable. I do not claim that one is better than the other because it depends on circumstances. For example, if you plan to rent and most of the rental fleet you plan to use consists of 6 packs or you own an aircraft that has a 6 pack and you have no intentions to switch to glass then you want to learn in a 6 pack. On the other hand, if you have access to a fleet of aircraft with both types, you may want to flip a coin if you are not sure or perhaps a rental-price differential will help with your decision. Generally glass cockpit aircraft rental rates are higher. If your future is flying to nearby airports or flying to local pattern, a 6 pack is a good choice. If your future is with the airlines, corporate flight, you appreciate modern technology, you plan to do a lot of IFR flight, etc. you may want to start with glass from day one. Personally I am biased, I lean towards going with glass.

BACKGOUND AND SOME HISTORY

There are ongoing arguments that deal with whether a beginner or the instrument pilot should do their training using a glass or a traditional 6 pack avionics set.

Glass is aviator's slang for a box with a liquid crystal display, often 2 displays, one that shows the flight instruments (PFD) and another that shows useful flight data, moving maps, engine parameters, etc. (MFD). The glass box has both a GPS and a VOR receiver. Most glass boxes display a horizontal situation indicator (HSI) and the pilot chooses which receiver drives the HSI.

Many glass installations are equipped with solid state devices that replace moving gyros and eliminate the need for a vacuum pump (One of Murphy's laws states that about 5 minutes after entering a cloud, the vacuum pump fails.)

A modern 6 pack has 6 circles cut out on the avionics panel, 2 rows, 3 columns, each cut out contains a flight instrument in the same relative position from aircraft to aircraft.

(A photo is coming here soon)

 In 1929 Jimmy Doolittle was the first to fly by using instruments without looking out the window. In 1937, the British Air Force standardized their fleet using most of the flight instruments we see today. The 6 pack has been with us several decades.

THE CURRENT STATE

The general aviation fleet is largely of the 6 pack variety, but glass cockpits are gaining in number because of retrofits to older aircraft and as standard equipment in many new production aircraft. Several companies offer retrofits which remove the classic 6 instruments and replace them with a single flat screen, Garmin and Aspen Aviation are examples of manufacturers who provide retrofit products.

THE DIFFERENCE BETWEEN THE TWO COCKPITS

Modern glass panels have fewer or no moving parts. The heading indicator and the attitude indicator operate from solid state devices which means no gyros. Data is displayed in liquid crystal rather than with mechanical "steam gauges". In the Garmin 1000 everything is solid state. There is no need for a vacuum pump on an aircraft with this unit providing the standby attitude indicator's gyro is electric. Since there are no gyros, there is no precession and no bearing surfaces to wear out which lead to inaccuracies and eventual failure.

A CASE FOR THE 6 PACK

  Some aviators are adamant that all initial training, especially at the pre-private and instrument rating level be conducted in a 6 pack. Their reasons vary. For the pre-private arguments that training should be in a 6 pack are generally of the nature that the glass presentation is too distracting and the student needs to learn to keep their eyes out the window. Glass somehow will cause a student to fixate on the glass components and keep their focus somewhere below the glare shield.

 The other argument, usually unspoken is: I learned how to fly with a 6 pack 30 years ago, so should you.

 I guess that is the best I can do for the pro-6 pack argument. Remember my confession about my bias?


A REBUTTAL TO THE CASE FOR THE 6 PACK

 Personally I find arguments regarding distractions caused by glass to be specious. As an instructor, I encounter this problem with students whether they are flying glass or a 6 pack. In both cases, the student needs a serious dose of what I call "the other function of the aviation chart" which is when I use the chart to cover the flight instruments. It is my observation that pilots of both cockpit types initially spend too much time looking at instruments. CFIs can catch this early by observing the pilot demonstrating latency errors leading to pilot induced oscillations (PIO) or jerky bank rates, excessive push and pull on the yoke and more. The beginner needs help to become aware of the substantial latency, especially with the instruments in the 6 pack.

  I have heard some say that an analog presentation is better than a digital or ribbon presentation for items like airspeed and vertical speed indications, it is somehow more human. To me, this is a religious issue. I cannot fathom why someone who is brought up reading digital time from a cell phone would be uncomfortable with digital airspeed. I can fully understand why someone who has been looking at analog gauges and 3-handed watches for decades finds it difficult to read a digital value or read a ribbon, but this means your ability to catch on depends on your own past experiences, not an "inhuman" characteristic. Also, the load of instrument interpretation is fatiguing. For example, as a pilot who learned to fly instrument on a standard VOR omnibearing selector and then switch to an HSI. The HSI is clearly a winner because it overlays heading with course and reduces a part of the interpretation load by a noticeable factor. Not only does the HSI closer to representing reality, it also reduces the amount of scan work needed by the pilot. There is nothing better than having instruments that are as close as possible to representing reality. Some argue that the 6 pack does, but this takes a lot of brain work by the pilot especially understanding position and the scan real estate is much larger than the small rectangle displaying airspeed, course and heading data, altitude, vertical speed, etc., on a PFD.

Another argument against the glass cockpit: the complexity and pretty colors are too distracting and the pre-private will fixate on the nooks and crannies of the device, being awed by pretty colors, knobs, pages, etc. and will not become a proper stick and rudder pilot. Again, this argument is pretty weak because it is up to the instructor to emphasize which features of the glass panel are relevant to the VFR student and keep the focus on those items. When the proper focus is set and enforced by the instructor, the glass panel is arguably easier because data the pilot needs to reference are in close proximity rather than spread out, sometimes over long distances in older cockpits that have undergone mystical retrofits. For example, VHF radios are often scattered over the panel (common retrofit condition on older aircraft) causing the pilot to sometimes have to lean to reach a considerable distance to tune radios or other equipment. Having all critical instruments displayed on a LCD in a few square inches of real estate is a good thing.

  Advocate for the 6 pack claim that you need to learn from that first and then learn how to use glass. I find this to be a weak argument. As an instrument instructor, I have found that in teaching for the instrument rating that the student who starts with glass has very little problem going back to a 6 pack. It does take a few hours with an instructor, but it is apparent to me that knowledge acquired from a glass panel with and HSI, etc. can easily be transferred to learning how to fly the analog gauges of a 6 pack. On the other hand, my experience has been that those who learned in a 6 pack have a much more difficult time of transitioning to a glass panel. It takes longer and leads to a lot more cussing than going the other direction. A lot of this is to do with using the various knobs and buttons. To successfully learn how to use either system, you need to a lot of repetition in the learning process. The glass system seems more complicated and in some ways it is, but remember that the comm radio, the nav radio, a CDI selector, an altimeter setting function, etc. are all in one box instead of scattered over several places on the avionics panel. A higher density of knobs and buttons exist, but not necessarily more, it's just a lot of stuff is in closer proximity. Then, add to this flight plan storage, and a host of other things one can add to an MFD (weather, airport data, etc.). No question it is a lot, but so is carrying a green AFD, the one in your pack on the back seat, and suffering through the experience of not having near real time weather at your finger tips when making long cross country flights.

Both panel types take a lot of time to learn and to use competently. If you think that you will eventually be using glass, why wait? Start early in your lessons where new things tend to stick with you.

Personally, I have heard no good reason to not use glass, but it does boil down to what is you intend to do with your learning experience after you get your ticket. IMHO, pilots who advocate against glass really do not present a strong argument. Analog gauges are not human and require a deep understanding of what it is that is producing the data that drives each gauge, how to interpret each item and how to take data from several instruments that are far removed from reality and process these between your ears to help acquire situation awareness. Much of this load is replaced by an HSI and a moving map. I am sure that the aviators of the 1930s claimed you needed to learn using low frequency radio ranging (A-N ranging) to really understand how to navigate before you used VOR when the VOR system came out in the 1940s. I am sure that many aviators lament the passing of the NDB/ADF combination, but personally I would rather take the non-precision GPS approach if available and it is getting hard to find airports without GPS approaches.

I guess if you went way back, pilots would tell you if you could not follow railroads you couldn't call yourself a pilot. I have seen the same phenomenon in blue water boating when the GPS came out and navigators using sextants would ask me what would happen if I dropped my GPS receiver in the water. My stock answer was what if you dropped your sextant into the water? I have a dry, spare GPS receiver, did you bring a spare sextant? That was when hand held GPS receivers were not cheap. Today they are a dime a dozen so to speak. There was an important advantage to using the GPS over the sextant - time. In seconds I could do what a skilled star shooter took a few hours to accomplish and I could do it even when it was cloudy and anytime time of the day. Yes, sextants are fun to learn to use for most of us, but not necessarily the best tool given today's technology.

The same is true in the cockpit. For example, using a G1000 I can immediately size up my cross and head wind components while on an instrument approach - just look at two wind vectors in the liquid crystal. I can recognize and correct approach errors much more rapidly than if I only had a CDI (near real time ground tracking data). The tools of the modern cockpit save time in assessing the external environment and this promotes a higher level of safety.

Most modern glass estimates the ETE to your next waypoint and the fuel expected to be consumed between your current point and the next waypoint and your destination. This can be calculated in one's head or by bringing along an E6B which has now fallen under your seat and is out of reach. Two of the most useful things that glass brings to the pilot is instantaneous ground track and ETE as mentioned earlier. When doing an approach with a 6 pack, at best I could sometimes get distance data to the next way point (DME or radial crossings). Distance, however, is marginally useful. I find time to the next way point a more human measure, how many more minutes do I have to do my next few things before I have to do a step down? Given distance only, I would have to estimate ground speed and then do a calculation to convert that to time. Anyone who does an approach with a 30 kt tail wind vs. a 30 kt head wind appreciates what I am getting at when I say that ETEs are much more useful than knowing indicated airspeed, guestimating ground speed, etc. Having an instantaneous track readout is wonderful because it clues the pilot to early deviations from a desired ground track, often before they show up in the deviation bar of the HSI.

A NOTE TO HELP THE INSTRUMENT STUDENT DECIDE

A general note first: Many instructors tell you need learn your IFR skills while hand flying, that is, not using any automation. I do not agree with this approach because it takes time to develop the finger skills to operate this kind of equipment just as it does for operating a modern glass panel with a flight management system. The only way you will become proficient with this equipment is to start using it from day one in your training.

Am I advocating that we never learn to hand fly? Heck no because stick and rudder is a must-have skill to possess if you want to fly safely. However, as an instrument pilot if you can hand fly an aircraft for at least an hour demonstrating good stick and rudder flight and you can do a hold and two approaches with no outside references while flying partial panel, what more do you want? No question, it is important to become a good stick and rudder pilot. Too much effort is placed on hand flying in the instrument environment even when a student is learning in an automated cockpit (glass + autopilot) producing pilots who are poor at using the automation. Many CFIs believe you need to hand fly and then at the very end of your instruction, learn to use automation. I respectfully disagree.

If you have an autopilot integral to the glass box (G1000 with a GFC700 autopilot) or even when it is not integral but nonetheless is a well integrated system (e.g., Avidyne/G430 with an S-TEC55 found in many older Cirrus aircraft) it will likely set an example for a learning instrument pilot on how to fly by instrument because of the smooth control, standard rate turns, etc.

Automation is your friend. Today automation is exceptionally reliable, but this does not mean 100% reliable (what man made apparatus is?). A modern autopilot will generally fly the airplane better than most pilots especially when the automation is obtaining digital input from reliable (no gyro) devices.

Yes, there is overhead in learning to use automation. There is also overhead in fully understanding the limitation of the automation. However, the return on investment in workload reduction and improved situational awareness pays back big time (IMHO).

If you start you instrument lessons in a glass cockpit and you have not had any glass experience, it will be difficult because you have to learn basic operations of the glass functions. For the pilot that did start with glass there are a lot of new things to learn that deal with IFR flight. Whether or not you have experience with the glass, it is best to undertake your lessons at a facility with a reasonable simulator incorporating the same equipment you plan to use in the aircraft. Also, consider purchasing a trainer-simulator that will run on your home PC/Mac so you can play and understand the features of the glass box you will be using. I like to think of trainers as a way to make sure I really understand what is going on - head work if you will rather than than use proficiency which will come with an training device or the real thing in the cockpit. Also, download either the user's manual or pilot's guide, preferably both and read it in while playing with your trainer-simulator at home.

If you are using a modern airplane with good automation, I would be wary of learning to first fly instrument by hand only leaving the automation part until later in the lessons. My approach has been to start with full automation and once the student becomes proficient, start breaking things so that they have to cope with a bad ADHRS, ADC, etc. or an autopilot that has gone south. Furthermore they must be able to operate under a heavy workload for at least an hour with these failure modes, demonstrating they can hand fly, keep on top of the workload and perform whatever approaches are available to them given the type of failure. And they have to demonstrate good stick and rudder technique at the same time using good trim and appropriate control input to keep the aircraft coordinated and flying at assigned altitude and heading or course.

Most of the glass failures will likely have to be experienced with the use of a ATD, especially when damage can result to opening circuit breakers in an aircraft and the manufacturer of the glass or the aircraft prohibit the use of breakers to simulate failures in the cockpit. Some failure can be simulated with Post-it paper while in flight, but some of these failures do not invoke various side effects, for example an inibility to display track up on an MFD when the ADHRS fails or flying an approach with a heading indicator not working on the HSI. You need to experience these failures on a simulator so that you can recognize them right away and understand how your scan will change.

SUMMARY

 Know your automation and how to use the knobs on your glass box like a concert pianist who has memorized a concerto. Later, learn how to fly with various components broken, including the autopilot. The instrument pilot must recognize each type of failure and what response is needed. It is imperative that the pilot always be in front of the automation by noting what is the next thing the automation going to do and making sure it does the next thing correctly. You still must stay on top of the gauges and monitor the automation. Even with this workload, it is much less fatiguing than hand flying, managing comms, dialing in nav frequencies, ID'ing localizers (instrument pilot), etc. all at once.

Remember that modern equipment, if used correctly is a wonderful workload reducer because it is not as fatiguing as hand flying and it gives the pilot more energy to use towards the safety of the flight. Another part of the safety aspect is due to the integration and display of information on the flight plan, aircraft systems and external parameters such as airport information, frequencies, weather and wind conditions.




1 comment:

Anonymous said...

The blog is absolutely fantastic. Lots of great information and inspiration, both of which we all need. Thanks.
Flight Instructor Course