BMI Tests For Pilots: Avoiding The Issue

(This article was originally published on my fitness site www.liftlazy.com but due to its inherent focus on aviation, I’ve posted it here as well)

 

The proposed addition of neck circumference and BMI testing to the airman’s medical exam is inaccurate, misguided and of limited usefulness. The impetus behind this screening is the recent spate of tired pilots making mistakes and even falling asleep while on duty. In one such incident it was later revealed that the captain had sleep apnea which was viewed as a probable cause for his falling asleep enroute (since sleep apnea is not contagious, the reason for the first officer also falling asleep at the same time was chalked up to fatigue). While this change to the medical exam affects all pilots, including those who fly privately, this piece will focus on air carrier pilots.

Aviation is under a constant media microscope and these incidents while statistically miniscule, nevertheless raise the suspicion of the public. Falling asleep at a job as hazardous as those that exist in aviation should not be tolerated, but using a questionable screening process should not be accepted in an attempt to create a solution to a condition that may or may not exist and most likely is not the primary cause of exhausted pilots. For the record, each year there are over 100,000 motor vehicle accidents that are attributed to drowsy driving. Despite the loss of 1,500 lives, so far no public safety department has mandated obesity or sleep apnea tests for motor vehicle drivers, even commercial operators.

Body Mass Index Accuracy

It has been proven that people with extremely high body fat percentages are susceptible to obstructive sleep apnea. It has also been proven that sleep apnea causes both hypersomnia and insomnia, impairs cognitive function and can lead to cardiac arrest in extreme cases. These facts are also not in question. What is troubling is the method being used to determine this risk factor in pilots, namely, the BMI rating.

BMI, or body mass index is a handy method for calculating a person’s mass to height ratio. As such, it is useful as a quick evaluation concerning obesity. The problem with BMI is that it is a very “dumb” equation; it does not know what it is measuring. A “smart” doctor, trainer, or clinician has to interpret the number and take into account other physiological factors (even the CDC states that BMI is not a diagnostic tool). Unfortunately, because BMI requires no specialized equipment or tactile measurements on the patient, it is widely used by people who have limited knowledge about the human body, obesity, bone density or muscle mass. This results in gross misinterpretations and misdiagnosis for people of various body types.

Another problem with BMI is that it leaves out critical factors such as age, gender, and body fat percentage. As people age, they naturally lose muscle mass unless steps are taken to preserve it (such as lifting weights). The loss of muscle mass, while detrimental, will show up as a reduction in BMI, leading the patient to think that they are getting healthier. Women on average have less muscle mass than men, resulting in more women being classified as healthy and more men as obese, even if the opposite is true. And most tellingly, if a person is 5’8” and 190lbs with 8% body fat, they will score the same BMI as someone who is 5’8”, 190lbs and 30% body fat (it is the same logic as saying that a Ford F-150 and a Ford Mustang will perform exactly the same since they have the same horsepower). One would think that scenarios such as these would be easily noticed and accounted for, however that does not appear to be the case in several well publicized instances.

In recent months, stories have come out where middle schools with good intentions unwittingly labeled some student athletes as “at risk” or obese based on a BMI calculation. The fact that nobody in charge of the program even understood how to deal with off-scale errors caused by a student having more muscle mass than their peers is distressing. Part of this rampant misinterpretation stems from our nation’s obsession with weight as the be-all-end-all indicator of a person’s health. Weight alone is a useless metric. It merely tells us how much of an effect gravity has on a given person. It does not tell us the distribution of body fat or muscle mass, which are the critical values that directly affect a person’s well-being. And as previously mentioned, simply possessing the stats of being 5’8” and 190 lbs only means that you are 5’8” tall and 190 lbs. Any other inferences must be determined by checking body composition.

As angry as the students and parents were at this mislabeling, imagine if your job relied on BMI numbers that may not have any basis in reality. It has been shown that it is very easy to make sweeping generalizations based on spurious data and then pass off any errors as anomalies. Will an airline ignore high BMI numbers in a visibly fit pilot, or will they tell them to atrophy away some muscle mass in order to lose weight? Alarms should be going off in the head of every pilot in America. If it can happen to children in school, it can and is about to happen to them as well.

Flight Fatigue

The cockpit of a modern jetliner can be a very sleepy place physiologically speaking. Noise fatigue from the slipstream roaring past the windows (a very effective white noise generator), reduced oxygen levels even with a pressurized cabin, and the inability to simply stand up and walk around are just some of the fatigue inducing factors present. Any one of these factors by themselves are hazardous enough to have volumes written about their attendant risks. Somehow, they are not even mentioned as a possible factor in pilot fatigue in this new screening process.

In fact it is entirely possible that it is an attempt to divert attention away from the fact that the new rest rules enacted by the Federal Aviation Administration have not fully accomplished their goal of eliminating pilot fatigue. This is only because airlines are not required to fully implement these rules until the end of 2013. Federal regulations now allow air carrier pilots a maximum of 9 hours of flight time and at least 10 hours of rest per each 24 hour period. To those who don’t fly for a living, a 9 hour workday does not sound that difficult and 10 hours of rest seems like it should be adequate. In reality flight time only accounts for loggable time in the aircraft (in airliners, the parking brake serves as the aviation equivalent of a time clock).

The new rules do a much better job of eliminating fatigue due to deadhead commuting and excessive duty times. Preflighting, checking weather, waiting for ground stops to expire, briefing, and all other tasks directly associated with preparing to fly an aircraft are limited to no more than 14 hours per day. Unfortunately, traveling to the airport, leaving the airport and checking into hotels all accounts for time that is not yet definable by the FAA.

Confusion abounds in the general public as to how a pilot halfway through a 3 hour flight can fall asleep. While that one flight is only three hours, it may be the second flight that day on the third day of a four day trip away from home. Anyone who works 9 to 14 hours is going to be tired. Anyone who works 9 to 14 hours going back and forth between time zones, sleeping in unfamiliar beds, unable to establish a consistent exercise regimen and not having access to healthy, agreeable foods is going to be even more tired. Now ask that person to stay alert in an environment that is almost custom built to induce sleep for four days in a row. This is the real reason why pilots are tired, make mistakes and fall asleep. When two pilots fall asleep and overfly their destination, or when critical mistakes are made due to fatigue induced cognitive impairment, the last thing that should be looked at is sleep apnea. Is sleep apnea a risk? Absolutely, but in the long list of causal factors it is not anywhere near the top.

The combination of desire to generate profit, maintain public confidence in aviation and ensure pilots are not forced into unhealthy patterns is a difficult river to navigate. The FAA has tried to close a massive loophole in their prior regulations via their current definition of Flight Duty Period. Airlines have historically exploited this oversight and were against changes to the Flight Duty Period limits (see page 112). Currently the issue is that duty time ends once the aircraft is parked, not when the pilot arrives at the hotel (we are assuming the pilot is in the middle of a multiple-day trip and cannot simply go home). It can easily take an hour to go from the cockpit to a hotel room, sometimes more. Assuming the pilot eats immediately, that leaves roughly 30 minutes before they are supposed to be sound asleep in order to take advantage of the “8 hour uninterrupted sleep opportunity”. In the morning, the reverse is in effect as it takes a similar amount of time to get to the airport and check in at the crew room. It is easy to see how the 8 hours of sleep can quickly erode to 6 or less. As a good friend who flies for a major air carrier said, “The new rest rules need to address the fact that we can’t go to sleep while making the first turnoff, nor can we wake up at V1.”

Instead of neck circumference and BMI tests,  there should be demands for better scheduling practices for all air carriers. Require that pilots get up and walk around the cabin for a couple minutes every hour (security rules be damned). Mandate that pilots take a few breaths from their O2 masks whenever they feel tired. Implore the FAA to close the final loophole in the definition of Flight Duty Period. Consolidate preflight tasks or delegate them to a dedicated ground crew much like military does with its crew chiefs. Install better soundproofing insulation in cockpits to reduce noise fatigue and hearing loss. Encourage airlines to create dedicated “pilot apartments” at their bases to eliminate travel time for the crews. Any one of these potential solutions solves multiple major issues facing pilot workplace health, which is the most effective way of mitigating the fatigue issue.

Conclusion

Should obesity screening be conducted? Considering that airline pilots must possess a 1st class medical certificate which can only be obtained after a battery of tests including an EKG, it seems odd that severely obese pilots are just walking around by the thousands. Many aircraft are tough to fit into even for an average sized person, so there’s yet another barrier to the truly obese sitting in the cockpit. But for the sake of argument, let’s say that there is a sizable population of obese pilots. There are far more accurate methods of determining levels of adipose tissue distribution than a distorted height to weight ratio. Aerospace Medical Examiners are certainly intelligent enough to use methods such as caliper skinfold or bioelectric impedance to make the necessary measurements. Then that physician can make recommendations on what the pilot can do to reduce their body fat percentage. Focusing on body fat, not weight, will have a far more effective result on the pilot’s overall health than zeroing in on one potential condition.

Flying aircraft is mentally and physically taxing. Pilots are still just mere mortals who have the same body the rest of us have. It requires food, exercise and sleep or it will not function optimally. To expect them to operate like machines is not realistic. Airlines need to accept this, the FAA has to continue to support this and pilots themselves have to live with this. Until it is determined that fixing the underlying causes is worth the cost, we will continue to see more pilots making fatigue induced errors and overflying destinations while fast asleep.

Suggested Further Reading

Center For Disease Control: “About BMI For Adults
Sept 13, 2011
 
FAA: “New Obstructive Sleep Apnea Policy” ; Fred Tilton MD
November, 2013
 
Mayo Clinic: “Sleep Apnea
July 24, 2011
 
FAA: “Fact Sheet – Pilot Flight Time, Rest and Fatigue
January 27, 2010
 
FAA: “Flightcrew Member Duty and Rest Requirements
December 21, 2011
 
The Sleep Foundation: “Sleep Studies
 
National Institutes Of Health: “Neck Circumference And Other Clinical Features In The Diagnosis Of Obstructive Sleep Apnea Syndrome” ; Robert J.O. Davies, Nabeel J. Ali and John R. Stradling
October 24, 1991
 
NHTSA: “Drowsy Driving And Automobile Crashes” ; Kingman P. Strohl MD, et al
 
International Journal Of Obesity: “Accuracy Of Body Mass Index In Diagnosing Obesity In The Adult General Population”; A. Romero-Corral, et al
February 19, 2008
 
FlightPhysical.com: “Summary Of Pilot Medical Standards
February 26, 2007

Six Degrees For Separation: One Way To Solve The DFW Airspace Issue

The airspace over Addison (KADS) is slated to be changed soon if the FAA proceeds with its plan to reduce congestion into Dallas Love (KDAL) and Dallas/Fort Worth (KDFW). The airspace change includes a lowering of the Class D over Addison from 3000 MSL to 2500MSL. While that may not seem like much, it is in an area where operations are already in a very tight fit with DFW traffic to the west, DAL traffic inbound from the east-northeast and large amounts of corporate, fractional, cargo and training traffic underneath at ADS. In fact, the final approach fix (JERIT) for ADS rwy 15 is at 2000 MSL, which would leave only 500 feet separation between IFR arrivals into ADS and DAL traffic at 2500 if this airspace change goes through. As it stands, ADS is already the busiest GA airport in Texas and in the top 5 in the United States.

The area of concern: The 3000 MSL roof of Addison's class D is slated to be lowered to 2500 MSL, leaving very little space for aircraft as big as MD-80s and 737s to maneuver. The proximity to DFW and DAL is noteworthy.

The area of concern: The 3000 MSL roof of Addison’s already highly modified class D is slated to be lowered to 2500 MSL, leaving very little space for aircraft as big as MD-80s and 737s to operate. The proximity to DFW and DAL is noteworthy.

There are numerous ways to avoid having to redesign the existing airspace. Although I’m sure some will suggest vectoring airliners further to the north and west before their southbound turn towards DAL, this is not efficient with respect to the jets. Anything that increases fuel consumption for the airlines is not only irresponsible environmentally, but financially. Likewise, the hundreds of businesses that rely on ADS should not be marginalized in the effort to reduce the impact to airliners. I am not writing this from the standpoint of “big airliners are against little piston planes”. Instead, I am writing this as the result of several years of observing, studying and testing new methods of utilizing existing airspace. After reading the NPRM on the changes to DFW’s airspace, I came to the conclusion that people may not be fully grasping the true capabilities of modern jet airliners.

The upside-down wedding cake design of Class B airspace is optimized for steep climbs and descents. Standard Class B has a floor gradient of 300 ft/nm out to the 10nm ring. This equates to only 1000fpm at 200ktas or 1250fpm at 250ktas. But again, this is for the floor and operations in excess of these values would be well contained within the airspace. With the advent of RNAV STARs and GPS approaches, creating 3D highways in the sky is no longer a fantasy but an easily employable system that works in VFR or IFR conditions. The only way to fit more aircraft into the volume of airspace already set aside is to increase the angle of descent at critical segments inside the Class B.

For separation and flow purposes, many congested terminal areas drop arrivals down 30 or 40nm out so that departures can climb unobstructed above them. This is because in areas like the DFW Class B, the proximity of DFW, DAL, ADS, AFW, NFW, FTW, GKY, GPM and RBD makes it very hard to get everyone where they need to be at the same time. When most of the non-RNAV STARs were designed, it was hard to conceptualize how to position aircraft three-dimensionally. Now that airliners and many corporate aircraft feature VNAV, FPA symbology and the ability to climb or descend in excess of 2000fpm, being able to follow a constant descent path is much easier to plan and execute.

As mentioned before, the standard floor gradient for Class B is 300ft/nm. Modern jet aircraft can climb at more than twice this rate under most conditions. Descending is actually more difficult to manage in some cases as an angle which is too steep will preclude deceleration to flap and gear speeds. Testing this theory in various sims, talking to pilots of different aircraft and flying the procedure in real aircraft has shown that an average glide angle of 6 degrees results in a power-off approach with no increase in airspeed (in reality the range was roughly 4.5 to 7.0). Depending on configuration, very low levels of power may be required to maintain airspeed. This power setting will invariably be less than that used during the current step-down method of approaching. This has tremendous advantages for noise abatement, fuel conservation, airspace utilization and wake turbulence avoidance.

Jets are not as responsive as light GA airplanes in the approach phase which is why a 6 degree glide path converts to a standard 3 degree glide path at some pre-dplanned distance from the runway, most likely 1500 to 1000 AGL (depending on the aircraft type and wind conditions). Further out in the Class B airspace, descent angles can be more conventional if satellite airport conflicts are not present, allowing jets to “pre-configure”; going to a minimal flap setting that would produce enough drag to keep speed from increasing in the descent. Some aircraft that are extremely clean with high inertia such as the A330 and B777 may require shallower angles or the use of speedbrakes.

Using this type of approach in the northeast sector of the DFW Class B would bring Love arrivals over Addison between 3000 and 4500 MSL (depending on where they are vectored from). This is a substantial safety margin for both Addison and Love arrivals. An additional benefit is that Love’s lateral spacing would not have to be modified from what exists today, reducing the potential for conflict with Dallas/Fort Worth traffic on the Cedar Creek Six arrival when a south flow is in use. Around the DFW Class B, departures leave the terminal area on north, east, south and west headings, while arrivals enter on northeast, southeast, southwest and northwest headings. This existing deconfliction works well with 6 degree descent angle as departures would not risk losing separation with arrivals.

The whole idea behind the 6 degree approach is to use what we already have without making any particular group of operators have to suffer. If the procedure works well in our airspace, it can easily be implemented nationwide for reasons as varied as traffic management, noise abatement and reduced emissions. Please try this procedure in whatever simulators you have access to. An example to test out is DAL runway 13L, crossing WADES at 7500 MSL, NITER at 1900MSL and conducting a normal visual or ILS once crossing the FAF. Since this is an angle-based and not a rate-based procedure, your VS will change as you descend and or change airspeed.

KDAL ILS 13L 6 Degrees

Runway 13L Dallas Love. Note the modified IF crossing altitude to produce a 6 degree glideslope to the FAF.

If you want to convert any IAP to a 6 degree variant, simply decide what your conversion altitude or intersection is (when or where you go from 6 to 3 degrees) and how far back from that point you want to commence the approach. Applying basic trig will net you the IF crossing altitude. For example using DFW’s runway ILS 17L:

FAF = GBUSH, 2300MSL

IF = RIVET, Unknown MSL, 12.6nm from FAF

sin descent angle x distance to FAF x nautical mile in feet + FAF altitude

((sin6 x 12.6) x 6076)) + 2300 = 10302 MSL at RIVET

KDFW ILS 17L 6 degrees

Runway 17L Dallas/Fort Worth Intl. Notice the modified crossing altitude at the IF.

In the meantime, please send the FAA your comments and suggestions on the proposed airspace change. My solution is not the only one and the more minds that work on this issue, the better.

http://www.regulations.gov/#!docketBrowser;rpp=25;po=0;dct=PS;D=FAA-2012-1168

 

 

Aerobatics Undefined

At the airport the other day, we got into a discussion of FAR 91.307, lovingly known as the “parachute” or “aerobatics” reg depending on who you talk to. The point of confusion was that an instructor had been told by another pilot a while back that doing spins was illegal since they weren’t wearing parachutes. The concerned pilot had seen 91.307 (c) and assumed that since spins exceed 30 degrees of pitch in most cases, that the reg had been busted. However, reading further to 91.307 (d) (2) it clearly states that spins and other checkride-required maneuvers are legal to fly without a parachute. In fact, there is no restriction on attitudes whatsoever provided everyone in the aircraft is a crew member. Actually, 91.307 (c) gives us a lot more latitude than we think. It states the following:

(C) Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft carrying any person (other than a crewmember) may execute any intentional maneuver that exceeds–
(1) A bank of 60 degrees relative to the horizon; or
(2) A nose-up or nose-down attitude of 30 degrees relative to the horizon

If you and a fellow pilot go up and do a 90 degree bank wingover, you do not need parachutes. If you go up solo and pitch up to 50 degrees and do a reduced-G float over the top, that’s legal without a chute as well. If you take your non-rated friend up, you either have to provide parachutes for the both of you, or keep the angles to the 30/60 limit. Also, if you and 3 other pilots go up, the 2 pilots in the back seats do not count as crewmembers so the 30/60 limitation will also apply. Note, that 30/60 is not the boundary of aerobatic flight. The litmus test for what defines aerobatics for your aircraft is in the operating manual. If your manual states that aerobatics are not approved except spins, Chandelles, accelerated stalls and Lazy-8s, then you know that rolls are out of the question. But nowhere in the FARs does it describe aerobatic as being flight in excess of 30/60 degrees. FAR 91.305 defines aerobatic flight as:

For the purposes of this section, aerobatic flight means an intentional maneuver involving an abrupt change in an aircraft’s attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.

That’s pretty vague, probably one of the most open ended regs next to 91.119. What defines abnormal? What is abrupt? And what is normal flight? I get the feeling when this was written, it was with point to point transportation in mind. As such, the regulation is conspicuously open-ended to allow for other types of operations that involve more aggressive maneuvering. The catch is that the FAA can also randomly define what “normal” and “necessary” is in response to a complaint or to issue a violation. But there is still another catch. “Aerobatic” also counts as a category of aircraft.

Say that I’m out over farm fields at 3,000 feet AGL in a utility category airplane doing wingovers. My airspeed never even gets into the yellow arc and my G-load never goes over 2.0. An overeager observer down below assumed that I was “hot-dogging” and “barnstorming” and called the FAA to say that I was doing “flips and tailspins in a Piper Cub” (it’s always a Piper Cub to non pilots). Short of having a data recorder onboard, its my word against theirs. Lacking this hard data, its very hard to validate what you did or did not do. And knowing what maneuvers were flown is critical in order to defend yourself. After all, it is entirely possible to do “aerobatics” in normal category airplanes without imposing more than 2Gs on the airframe. Before you get angry and call me dangerous, I’ll explain.

While it would be tempting fate to do a snap roll in a normal category aircraft, you can freely apply full control deflections (well below Va and in one direction only), pitch, roll or yaw to whatever attitude you like. The danger is in building up too much speed in an extreme nose low attitude and needing to pull more G than the airframe is rated to (that’s when you hear the loud POP and then enjoy the rush of the wind as your wingless, tailless airframe plummets to earth). However, an abrupt change in attitude does not always imply a high load factor. Imagine using full aileron in a Piper Saratoga to roll into a steep turn (50 degrees) quickly. Was the maneuver abrupt? Compared to “normal flight” in the same type airplane, yes. Is the attitude abnormal? Not really? Was the acceleration abnormal? Not even close. So was it aerobatic? Ask your FSDO…seriously, find out how they define it.

The more knowledge you have about what you’re doing, the better. An untrained observer may say that they saw an airplane doing “acrobatics” and “stunts” when really you were doing Chandelles. If you can confidently state what maneuvers were performed along with some rudimentary info on entry altitudes and speeds, it may convince whoever is inquiring that you aren’t just throwing the stick around to see what happens. Unfortunately, society loves to point out when they think someone else is doing something wrong or unsafe without actually knowing what was going on in the first place. If you take the chance of actually having fun in other than straight and level flight, there’s the risk that someone with an iPhone is going post video of everything you did while commenting on how “unprofessional” and “dangerous” the pilot of that little airplane was.

Quite frankly, every time you fly, you are at the mercy of someone’s self-narrated cellphone video (even an airplane well above 1,500 feet AGL will show up on a phone camera). The only way to protect yourself legally is to make sure you understand the regulations fully. However, the only way to keep yourself alive is to make sure understand the aerodynamics fully. Use 91.307 to your advantage. Go up with an instructor and practice really unusual attitudes. Take some aerobatic lessons. Get used to the fact that airplanes operate in a three dimensional ocean of air. If your comfort zone ends at 30 degrees of bank, work your way up to 45 and 60 degrees (maybe even a little beyond). Once you experience that an airplane will not just drop out of the sky because the bank angle increased beyond 45 degrees, you will have a lot more confidence in handling it in all phases of flight.

There Is Never* Too Much Airplane

* Let’s get the disclaimer out the way up front. When I say “never”, I’m not talking about your fringe elements. You know the guy who somehow managed to buy a functioning SR-71 for trips from Tamiami to Beale. Nor am I talking about the person who has 50 hours in a Cessna 152 and buys a P-51D because he’s “always wanted one”. I’m ruling these aircraft choices out because they are pretty rare. This article is meant for the pilot who wants to upgrade from a trainer to a faster/larger aircraft in the same class and category and is intimidated by the change in cruise speed or engine size.

Part 1: Speed

“Speed is relative. If he’s doing 600 and you’re doing 600 what’s the difference? Zero.”     ~ Brigadier General Robin Olds

When sitting around hangars, the talk occasionally brings up some guy who allegedly went from a Cherokee to an Arrow and got so far behind the airplane that he was just contacting departure at the same time he was beginning his initial descent to the destination. And the talk will progress to how complex the new airplane is and how much power it has, which inevitably leads to someone belting out “It’s the same old thing, it was waaaaaay too much airplane for him.” At which point I sigh and hold in what I really want to say.

What I really want to say is “That’s nonsense.” Simple and to the point. Sure there may be some truth in not taking someone who had an intro flight in a Skycatcher and suggesting that they do the rest of their training in a T-38. But the chances of that happening are very, very remote. It doesn’t help pilots to keep them in slow airplanes for hundreds of hours anymore than it helps to teach them how to fly in said T-38. How can I say this with a straight face? Go to the FARs and look at Part 23.49c which regulates stall speed for all single engine aircraft (we’re ignoring twins in this discussion). No aircraft can stall above 61 knots in landing configuration unless an equivalent level of safety is demonstrated with respect to occupant restraint. This stall speed important because it’s a benchmark for any certified single engine aircraft.

Example: Bill Generic wants to upgrade from a Cessna 172 to a Piper Saratoga. Aerodynamically, it’s not a huge leap. In terms of systems of course, it is a completely different aircraft and if Bill doesn’t get transition training, he has a few cotter pins loose. But once Bill finishes training and goes out on his first solo cross countries, he may end up blasting past intersections or call on the wrong frequency because he’s not keeping up mentally with his progress and there’s no instructor/mentor next to him to help coach. The easy way for Bill to fix all that is to simply pull the power back. No he won’t drop out of the sky. No he won’t be hanging on the edge of a stall. Since all singles are created equal in that they cannot exceed 61 knots Vso, it means you can cruise any single between 100 and 120 knots without any superhuman effort at all.

Will the faster airplane like loafing along so slowly? It may not handle exceptionally crisp and depending on how far back Bill has to pull back the power, the engine may start getting warm if he tries this at 2000 feet over Death Valley. But done with agreeable weather conditions, this is a great way for him to get used to progressively faster speeds. It may take 3 or more trips for he becomes comfortable spanning the gap between 110 and 170 knots. Or he may be fine after one leg of continuous increases in speed. But the important part is that he can adapt at his own pace. The throttle doesn’t control power, its controlling time.

The ability to control time means that while doing transition training and even afterwards, a pilot can get used to the checklist items and internalize procedures. Your aircraft upgrade may have a turbocharger or oxygen system or cowl flaps or even extra fuel tanks. More time gives you a cushion for making sure these systems are working the way they should and that you understand why they’re doing what they’re doing. Waypoints passing too quickly and your map (some of us aren’t totally paperless yet) can’t get turned to the proper side fast enough? Pull back the throttle/time controller and slow things down.

Landing and approaches are another place where the 61 knot rule levels the playing field.  Surely you practiced rectangular patterns at altitude, so making the base and final turns shouldn’t be an issue but all the same, give yourself more time in the form of a slightly wider and longer pattern. On downwind, fly whatever was recommended but 90-100 knots is a safe range (1.47 to 1.63 times Vso) where you have some wiggle room in case your aircraft bleeds speed quickly when flaps or gear come down. If that happens, use the time controller in reverse…push the throttle up so that the bleed rate slows and you have more time to adapt to the aircraft’s idiosyncracies. The standard 1.3 Vso approach speed for the 61 knot aircraft comes out to 79 knots (just say 80). Flying final at 80 knots is an easy and safe target if for some reason everything the instructor taught in transition leaked out of your ears. If you’re being vectored for an approach and the controller wants you to hold 170 knots to the marker and you aren’t comfortable doing that yet, tell them you are unable. They don’t need to know why and if they do ask, mention something about monitoring a fluctuating sonidecimeter indexer. By the time they figure out you’re full of it, you’ll be making the second turnoff.

Part 2: Power

Power is relative too. In my view, too much is made of horsepower being the primary indicator of performance. The FAA categorizes any aircraft with over 200hp as high performance. Because of this, you will often hear the same people who griped about “too much airplane” complaining that a certain airplane had way too much power. While there are cases when this is true, 90% of the time you can never have too much power. High performance is what you make of it, what you wish to measure and what you’re used to.

For a real life example, take a Rockwell Commander 114 and a Pitts S-2C. Both use a 540 cubic inch, 260hp engine and both are technically high performance, but that’s where the similarities end. The Pitts can fit 2 people very snugly and climb at 2900 fpm. The Commander can fit 4 in leather-bound comfort and climb at just under 1100 fpm. The Commander has a 1000nm long-range cruise while the Pitts is limited to 247nm. We could go on and on but the point is that power gives you radically different performance based on what you want to do with it. The Commander is intended to carry people places, the Pitts is made to go up, have some fun and come back within a relatively short time. Which one is high performance? Depends on what you want to do. Flying an advanced aerobatic sequence complete with a pull-push-pull humpty and snap rolls on a 45 downline? The Commander is going to be a letdown. Need to take 3 people nonstop from Teterboro to Nashville in IFR conditions? The Pitts would not be a good choice. What if payload is the determining factor in what you count as high-performance?  Looking at a much larger aircraft, the Cessna Caravan, has 675 shaft hp from its turboprop engine, but because of its rugged design the aircraft max cruises at 186 knots. By comparison the Cirrus SR22T has less than half the power (315hp) but max cruises at 214 knots. But while the Cirrus can only hold 4 people, the Caravan can carry up to 14. If lifting payload is the performance factor your type of flying depends on, the Caravan is the clear winner. And what about your own experience? What you have flown in the past and what you are flying currently has a lot to do with this perception. If you had a PC-12 and are downgrading to a Commander, you may not consider it to be high performance by comparison. If you are coming from an MX-2, then maybe the Pitts isn’t such a wild ride. But if you’re upgrading from a Diamond DA20, you’re most likely going to be wowed by either aircraft. Performance is just as relative as power.

Perhaps the regs should focus on acceleration, climb rate and cruise speed instead of power for a definition of high-performance. This is probably what the FAA intended people to focus on all along but we ended up getting fixated on the semantics of 200 vs 201 hp. Here is an example of why horsepower can be a dead-end. Take an airplane with a pretty anemic power to weight ratio of 16 to 1, meaning there are 16 pounds of aircraft per horsepower. With a 100hp engine, this fictional airplane will weigh 1600 pounds. But what happens when we scale everything up by a factor of 3? The horsepower explodes to 300…definitely high performance by federal standards. But the weight also balloons to 4800 pounds. And in case you didn’t notice, the power to weight didn’t change either which means acceleration and climb is going to be pretty similar (provided the wing loading remained constant). Glancing back at our earlier examples, we’ll compare the difference in power loading for the Commander and Pitts. The Commander has a 12.5lb/hp loading while the Pitts has 6.6lbs/hp. That’s a massive difference in the amount of weight each horsepower has to work with and why the performance figures are so radically different for the same horsepower engine.

Part 3: The Moral

Yes, upgrading in aircraft will take time and money. Get transition training, talk to pilots and owners of the same aircraft first. Learn the little quirks that aren’t written in the operating manual. Study the systems and know little things like how to start the engine. Nothing makes a passenger reevaluate their friendship with you like watching you fumbling around with throttles, mixture knobs and primers on the ramp and saying “It normally doesn’t do this.” Things like starting the engine are and knowing how the fuel system works are pure study items. The things that you can’t learn from a book are your own comfort zones. The only way to learn that is by actually doing it in increments.

Hearing people repeat over and over how hard it is to keep up with fast airplanes and how so much horsepower will ball you up like a Bf109 in a crosswind does not boost confidence. But remember that they’re just repeating what they’ve heard. If flying high performance aircraft was so hard, nobody but astronauts would be doing it and the last time I looked, there’s plenty of non-astronauts in Meridians, Stationairs, Bonanzas and the like. It will just take a little getting used to. Be kind to yourself and don’t expect to go full-tilt right out the gate. Remember, nobody goes 220mph out of turn 4 at Talladega their first time in a race car either.

Virtual VFR and Pilot Safety

Don’t Worry, There Won’t Be Any J-3s On An ILS To Minimums

 Original date: August 2, 2011

"I'm sorry sir, these flat panel displays are for airliners only. Have fun with your morse code identifiers."

Warning: This blog is filled with aviation terminology that may be objectionable to land-locked readers.

This all started after reading Mac McClellan’s blog on head-up displays in light aircraft. I posted a response and one of my friends who happens to be an airline captain saw it and responded to my response (don’t you love the internet?). We’ve been going back and forth about the benefits of advanced technology for general aviation aircraft. Specifically, it was about synthetic vision and how it could create Virtual VFR regardless of weather conditions. His stance is that GA pilots don’t need super advanced instruments and information systems because it will make pilots fly into conditions they shouldn’t be in. My stance is that it will make those who take the time to learn how to use it much safer.

The sticking point in any field is that new technology that makes things easier is often seen as a crutch by those who did without for the majority of their lives. When GPS began showing up in aircraft, people said “What will you do if it all fails?” I would then point to their stack of navcoms, adf and loran receivers and ask them the same question. Stuff fails no matter how high tech or low tech it is. Dealing with failures is the burden of the pilot. The mean time between failures with modern electronics far surpasses any analog, transistor or vacuum tube based system that bore the generic label “computerized” in previous decades. Automatically that is a huge benefit not just for safety but for life cycle operating costs.

The other problem brought up during the initial GPS revolution was that people would forget how to navigate or look for other aircraft. That is a problem, not so much of the GPS but of people not knowing how to divide attention, especially in busy airspace. I remember several times with my instructor when we’d spot an airplane (or worse, get bounced from behind) I’d say “Did he even see us?”. To which Marty would always have a witty comeback like “Why don’t you get out and ask him. Think it’ll make a difference?”. I have no idea why the overtakers didn’t see us but a distraction is a distraction. I don’t care if its GPS, an ADF or some poor soul with headphones on listening for “dah-dit dah-dit” on the four course.

Flying in a general aviation aircraft, regardless of what we tell passengers is a more risky activity than driving on average. However the risks can be adjusted based on a pilot’s skill, comfort level and aircraft capability. Maybe a particular pilot doesn’t like flying in clouds, flies only for pleasure and operates an aircraft equipped with VFR only steam gauges. However this pilot wants to upgrade to a 3 tube EFIS system combined with a HUD. Should we deny them advanced navigation and weather information based on the assumption that he is going to suddenly start flying between level 5 thunderstorms? Should information-dense systems be the sole domain of the turbine fleet and business jets? If the light airplane pilot wants to fly a 300nm trip, is it fair to make them use less capable avionics, ostensibly to keep them out of trouble?  

There's a lot of information, but how easy is it to interpret under stress?"

Being able to navigate a couple hundred miles through a high-pressure system without super-duper graphics and satellite weather should not be too difficult for any pilot. A basic GPS or (gasp) a stack of VOR receivers can get you just about anywhere in the United States. But the cushion of safety for those who choose to learn everything that their super-duper system can do for them is undeniable. The objective for VFR pilots is to use extra information to stay away from weather (terrain shouldn’t be a problem since if they’re VFR they should be able to see it). To say they don’t need it because they’ll start flying into frontal systems is like saying that airline pilots shouldn’t have terrain avoidance systems because they’ll see where the ground is and fly into it.

IFR flight on the other hand is a more difficult situation because there are so many variables in the types of aircraft, the types of missions, and the weather conditions at any given place or time. There may be the person in the Cirrus who is cruising at 11,000 feet on top of a cloud layer and wants to know the exact position of the hills hidden beneath those clouds. Sure he can use an IFR chart and know that by staying above the MEA he’ll be fine but let’s use the favorite example of instructors: What if the engine quit? Synthetic vision cannot dead stick an airplane onto an open farmer’s field automatically, but it does give the pilot far more information in an emergency situation with regards to wind direction, terrain location, obstructions, etc.

Take a single-pilot King Air on an ILS on a scuzzy day. The pilot has approach charts that show what the decision height is, how far from the touchdown zone that will be, what the missed approach procedure is, etc. And since the pilot is IFR rated and trains in a simulator at least once a year, it should be no big deal. However, if there is a distraction, or a problem with the aircraft, a small mistake could be made. To the delight of lawyers everywhere, I will be completely honest: pilots do make mistakes (if you don’t believe me, ask the NTSB). The majority of accidents are not one massive brain-fart but a series of smaller errors that compounded until the snowball became an avalanche. By providing easy to interpret data, the pilot’s mind is freed to deal with any other issues that arise during times when the mind is approaching task-saturation. So now while dealing with a generator problem, a sick passenger, or just an unfamiliar approach, the pilot is able to see the image of where the runway should be and cross-reference that with the standard charts and data. This removes all doubt as to the aircraft’s location and where it will be in the next 15 to 30 seconds. Breaking the links in the accident chain should be reason enough for encouraging use of such equipment.

Information-rich technology is not for every style of flying. I admit, it would be odd to fly a Stearman with a HUD. And a Cessna 152 that is only used for $200 dollar hamburger runs (inflation hurts, doesn’t it) would not need an extensive weather suite and electronic IFR charts loaded into the system. Am I in favor of putting EFIS and HUDs in everything from 

Open cockpit EFIS

light sport to piston twins? Honestly it doesn’t matter what I think. If the pilot/operator feels that the technology will be a benefit to their type of flying, then full support should be offered for getting that equipment into their cockpits. I was in Woody Saland’s hangar a while back and was intrigued by the fact that his AirCam had synthetic vision EFIS, EICAS and an autopilot. Why would anyone want so much technology in an open cockpit airplane? Then it hit me: To make the task of converting numbers, radials and performance figures into an instantly interpretable view of what your aircraft is doing. With so much of your mental capacity relieved of that repetitive task, you can actually enjoy the act of flying.