It’s Wi-fi, Not Wi-Fly

For the record, I’m not an IT specialist, a security analyst or a person with top secret clearance (my clearance is bottom secret only). I am however someone with a fairly extensive knowledge of aircraft, systems, avionics and other stuff that’s related to being off the ground at high speeds. Therefore, I’m going to address the aircraft systems side of the current wi-fi hacking issue.

Recent articles have stated that it is possible to hack into an aircraft’s controls via a wi-fi connection. Some hackers have even publicly stated that they could and have get into an airplane’s avionics (and they probably got a nice visit from gentlemen driving cars with government plates soon thereafter). The worst case scenario that keeps getting bandied about is a passenger taking over the airplane from a laptop and making it go wherever the hell they want. This may be possible on some astronomically small level, but in reality it is not very plausible with current aircraft designs.

Everyone always talks about how airplanes are flown by computers. I’ve been at airshows where people next to me confidently tell whoever will listen that “Those Blue Angel pilots aren’t even doing anything. The computers are flying the airplanes, it’s all a program.” Passengers often assume that the pilots up front are just following commands from “ground control” and that computers will be able to take over completely by 2017. This is what happens when an industry touts its technology rather than its technicians…the machines become the heroes.

Part of this is a misunderstanding of basic aircraft systems, which considering the level of knowledge most people have about aircraft in general, is not surprising. Aircraft may be “flown” by computers, but human pilots tell the computers what to do (and if the computers get a a superiority complex, the humans can override the machines). It’s the same as how computers in your car govern much of its operation, but you still turn the wheel and hit the pedals manually.

Aircraft are a weird combination of old and new technology designed to provide ease of operation, redundancy and graceful degradation. Save for a few military jets (the statically unstable F-16 as a prime example), virtually all aircraft have a physical connection from the cockpit controls to the control surfaces. This ensures that even in the event of a major emergency, the pilot(s) will be able to maneuver the aircraft to a landing. These physical connections may be steel cables, pushrods, hydraulic actuators, screwjacks or a combination thereof.

While the old technology works great for ensuring that pilots can continue to fly even after malfunctions, the new technology is perfect for making the aircraft more precise, more capable and easier to manage over a variety of situations. Of course, this all hinges on the pilots understanding and being masters of all the different modes that the automation systems offer (they do and they are). Some of these systems include:

  • Where-Are-We Systems: Inertial navigation systems (INS) are self contained units that use laser ring gyros to determine where the airplane is at any point on the planet with extreme accuracy; global positioning systems (GPS) that use satellites to triangulate the aircraft’s position. These prevent getting lost, which as a rule tends to erode passenger confidence.
  • What-Are-We-Doing Systems: Attitude Heading Reference System (AHRS) that uses accelerometers to figure out what the pitch, roll and yaw state of the aircraft is; Air Data Computers (ADC) takes analog inputs from the pitot-static system and Angle Of Attack (AOA) probes to provide the pilots and other computer systems with information on how fast and how high the airplane is.
  • Do-What-I-Tell-You Systems: Input interfaces like the Control Display Unit (CDU) allow pilots to enter data into the Flight Management System (FMS) to create and manage flight plans, and Autopilot Mode Control Panels (MCP or FCU) that give the pilots the ability to change autoflight settings or most importantly, disengage automation if the situation calls for it.
  • How Are We Feeling Systems: The Central Maintenance Computers (CMC) and crew alerting systems (EICAS) check the health of the aircraft, run checklists and alert the pilots to any unusual situations. These are the computers that stole the job of the flight engineer…the third guy in the cockpit you often see in old movies.
  • I-Can’t-Let-You-Do-That Systems: In some aircraft there are systems that prevent pilots from exceeding certain limits. Examples include Thrust Management Systems (TMS) that protect engines from overheating or overspeeding and commands the autothrottle system, and Flight Control System computers (FCS) that process information from various sources, determine what the pilots are asking for in terms of maneuvering and either direct or implement those inputs to the control surfaces and engines.

At this point you may have noticed that the aviation industry loves acronyms. You also may have noticed that there is not one single computer that controls the airplane. Probably the most important system in the bunch, the FCS is usually comprised of several computers all speaking different languages. If one computer doesn’t agree with the others, it is overruled. If two computers don’t agree with the other two, the fifth one kicks in as a tiebreaker. Needless to say, the implementation is far more complex than linking a couple desktops together with an ethernet cable, but the theory is straightforward.

Beyond just being the Supreme Court of the airplane, the FCS also acts as a mediator between the pilot’s inputs and control surface positioning. This provides protection against exceeding certain attitude limits, speeds or energy states. In some aircraft, full-time protection is provided to prevent pilots from This protection is present even if the pilots are flying the aircraft by hand. In other airplanes, protections are more limited and mostly confined to autopilot modes or dampers that reduce unwanted transients in a given axis. In any case, the idea is to prevent a pilot-induced situation from damaging the aircraft.

There is an even more advanced group of aircraft that operate with what is known as fly-by-wire. These aircraft have virtually no mechanical connections to control surfaces. They use electrical signals produced by force sensors or position transducers to trigger the movement of a self-contained hydraulic actuator near the control surface. The FCS in this case becomes the equivalent of Judge Dredd whereupon it declares “I am the law!” as it pertains to aircraft operation (seriously, the protections are referred to as Control Laws…if you flew an Airbus you’d be cracking up at that last pun). Pilots at that point are “educated suggesters” who tell the airplane what they want and the airplane decides if it’s a good idea or not. For example, if a pilot sees a giant condor while climbing at 400mph and yanks back on the controls, instead of allowing the wings to be ripped off, the FCS will say “Listen, I know that massive bird startled you, but if I let you pull as hard as you’re asking, we’re going to have bigger problems. I’m going to limit you to 1.8G rather than 5.3G. You’ll thank me.

Different manufacturers have different views on how this should be implemented. Boeing prefers a more pilot-centric interface while Airbus leans towards a computer-centric operation. Both methods have their advantages and drawbacks. As creepily cybernetic as this sounds, commercial fly-by-wire aircraft still have mechanical reversions so that in the event that all the computers decide to divide by zero, the pilots can still fly the aircraft to a safe landing.

What is the point of me writing all this aerotech babble? To try to explain that aircraft control is a complex and well thought out architecture. Most of the robustness is there for nature and emergencies. Situations like getting struck by lightning cannot affect the operation of the critical avionics, therefore aircraft are tested by literally getting zapped by a massive Tesla coil before they can be certified. The loss of an ADC cannot cause the airplane to go out of control, therefore multiple ADCs are installed. The total loss of electrical power cannot cause the airplane to shut down its fly-by-wire controls, thus a deployable ram-air turbine is installed for just such an emergency. In the face of all these natural and mechanical threats, it therefore seems overly simplistic to assume that a hacker could seize control of an airplane.

Herein lies the issue with “laptop terrorist” scenario: There is no conceivable way that an individual can seize control of an airplane through a wi-fi signal without someone up front (read: pilots) figuring it out and taking corrective action. If for some implausible reason both pilots don’t notice the change in flight path, it is guaranteed that the air traffic control center responsible for the flight would notice that an airplane under positive radar control just decided to stroll off on its own. Even if someone could find holes in a firewall and hack their way through all the different systems to get to the autopilot, controlling the aircraft is not as easy as typing “C:\>FLYTOCUBA.EXE”.

But for argument’s sake, lets say Super Hacker can figure out how to change the heading or altitude. For all intents and purposes, control of the airplane is now in the hands of some guy in seat 37Q and everyone is doomed, right? Wrong. The pilots are not helpless, nor are they at the mercy of computers, laptops or otherwise. All they have to do is pull the disconnect switch on the autopilot. In the event that Super Hacker figured out how to disable that function as well, they’ll just pull the A/P circuit breaker, then walk to the back and smash his computer over a beverage cart.

All joking aside, this threat illustrates the continued need for humans to be in the decision loop when it comes to flying commercial aircraft. The insistent push for total automation especially in the wake of the Germanwings catastrophe is an emotional reaction that ignores the advantages of having both humans and computers working together. When backlit against the threat of nefarious individuals who wish to do harm, these advantages are even more important. Nevertheless, aircraft will become increasingly more automated in coming years and protecting them against electronic threats will be just as critical as protecting them against ice and microbursts.

For now, you don’t have anything to worry about.

Know It All…Or Not

If I have to repair this in flight, something is beyond horribly wrong.

If I have to repair this in flight, something is beyond horribly wrong.

I punched a fist of joy into the air upon reading Bruce Landsberg’s recent editorial in the February 2014 AOPA Pilot magazine. He addressed the topic of useless knowledge being taught rather than critical overall concepts. I’ve been saying this very same thing for years, but since I don’t have a type rating in the Saturn V, I’m viewed as a dangerous menace to the national airspace system. Thankfully, his article lends credence to my stance that we often focus on useless data in aviation that is of little practical or emergency use. We should be looking at the big picture items with a lot more interest rather than the little details that only impress other pilots or examiners.

While I’d love to claim credit for being a maverick as it relates to the idea of not needing to know everything there is to know about an aircraft, NATOPS was leading the way with this mindset years ago. Anyone who has flown in the US Navy knows that the manuals for aircraft are purposely designed to exclude excess systems information. The only things that are included are things that the pilot either has control over, or any system that can cause a hazard to continued flight (and how that hazard will manifest). The reason is simple: mechanics fix airplanes and pilots fly them. This division of labor is present even in civilian aviation where the FAA makes it a point to tell pilots that save for a few preventative measures; they are not allowed to be a mechanic on their airplane.

I believe this focus on knowing every system in detail is a holdover from the good ole days of aviation (which we simply cannot move on from it seems). Systems were very complex and highly mechanical in nature. All of them were controlled by human beings, hence the plethora of people in the cockpit of vintage airliners. The flight engineer literally made sure all the systems operated the way they were supposed to. The pilots flew and if present, the navigator made sure they didn’t get lost. The crew had to understand their piece of the equation and at least a little bit of the other guy’s in order to pull off the flight.

Fast forward to today where the airplane’s flight engineer is the ECAM that collects and displays information about the status of every system several times per second. You literally don’t need to know much more from an operational standpoint for many systems other than “Is it on?”, “Is it off?”, and “Should it be in that state?” A friend of mine flies a Brazilian-built regional jet and has to memorize the starting and operating temps, abnormal shutdown criteria, and various RPM ranges…for the APU. Meanwhile, the only direct control over this device the pilots have is an Off-On-Start switch, a Stop switch and an emergency fuel shut-off switch (in the event of a fire, overspeed or overtemp, the APU FADEC will automatically command a shutdown). Does it make sense that three switches with a total of five possible selections warrants memorizing the type of compressor, every temperature limit, every RPM limit, and the type of cooling used by the APU?

While it may be interesting information to know, the role of a modern airline pilot is not to play mechanic. It is to fly the aircraft from Point A to Point B. If there is a problem with the aircraft, they write up what isn’t working and if it isn’t on the MEL, continue flying until it can get fixed by the maintenance guys. It’s not about being cavalier, it’s about being efficient with specialized skills. Ask yourself if there is any way for a motivated captain to crawl back to the tailcone in flight (there isn’t since the APU is surrounded by a firewall). Even if they could get back there, what could they do to fix a problem? Last time I checked, airlines don’t hand pilots toolkits with their Jepp revisions. What if more time in review and sim sessions was spent talking about things that are more likely to be encountered in day-to-day operations, rather than the specifics of a component that the pilot will most likely never even see and has limited control over?

Air France 447 is a perfect example of why broad scale knowledge is critical. An aircrew faced with a rare and confusing situation may be spring-loaded to go to a rather complex solution due to the way we train them. Ignoring the control input issues, had the crew been taught to look at the big picture of where is the information coming from, they might have considered the fact that the FMGS was likely showing correct groundspeed based off the GPS signals it automatically updates with. Additionally, the combination of pitch and power for a given flight condition would have led to suspicion that the EFIS PFD was at least partially lying (and thus to look for independent data, such as the FGMS). This is not an indictment of the crew, but a look at how a few seconds to consider the big picture before zeroing in on a smaller picture solution may prevent accidents like this from happening again.

The Air France accident was not the first time a high performance jet was lost at night in the vicinity of thunderstorms due to faulty instruments. A nearly identical situation occurred in a B-58 on February 14th, 1963 when the pitot tube iced up and the pilot began unknowingly following erroneous airspeed data. When the controls felt sloppy and he suspected something was wrong, the pilot cross-referenced with the Machmeter, but this was also giving an incorrect reading. It wasn’t until the pilot asked the navigator (who had an independent pitot system) what the airspeed was that he realized the delta-winged bomber was about to drop out of the sky. The aircraft ended up departing controlled flight and the crew members were forced to eject (see the article “B-58 Hustler” by Jan Tegler in the December 1999 issue of Flight Journal for the entire story). Hopefully with changes in training and multiple-source independent airdata, there won’t be any more accidents like these.

Aerodynamics is another place where we overthink things to the point that it might be causing poor decisions in some situations. My favorite horse to flog is the recent bank angle conservatism being taught in the United States. There is no magic law of aerodynamics that says if you bank 31 degrees at 999 feet AGL, your airplane will autorotate into a flat spin. Although the intentions are good, the source of this fear stems from the g-load charts that we all looked at as student pilots. In a 60 degree bank, load factor is doubled and stall speed increases substantially. The only problem is that this is only true if you attempt to maintain altitude. It is not even close to accurate in a descending turn. Nor is it accurate if one is flying an airplane with a lot of excess power/thrust. We have become so obsessed with the book numbers that the bigger picture of how aircraft actually fly in three dimensions is being lost.

Don't freak out if you hit 60 degrees of bank while descending.

Don’t freak out if you hit 60 degrees of bank while descending.

There are student pilots (and an increasing number of certified pilots) who will either fly C-5A sized patterns, or make skidding turns in order to keep the bank angle low. The former negates the engine-out glide advantage of a close pattern while the latter actually is a perfect setup for a spin. To be honest, a bank beyond roughly 30 degrees is not really necessary at speeds under 80 knots if the proper lateral spacing is used. The trap is when the pilot comes in a lot faster or much closer due to ATC request or their own misjudgment. All of a sudden as they notice they’re going wide, the rudder gets kicked in and opposite aileron starts to hold the bank angle constant. The saving grace is that usually this situation is created by having a surplus of airspeed so a spin isn’t likely provided they return to coordinated flight fairly quickly. Rather than worrying about a chart that isn’t applicable to their conditions, they should be taught the confidence to put the airplane where it needs to be to get where they want to go.

Again, before people get riled up, there is a time and a place for sticking to book numbers. Early 727 pilots who tried to eyeball the landings as if it was a DC-3 with jet engines learned about the importance of sticking to the book. But the book isn’t magic. The numbers it contains are the sum of the properties of the atmosphere plus the aircraft’s design plus the systems installed. If it takes the engines 9 seconds to spool from flight idle to “Oh crap” thrust, the obvious solution is to not be low and slow while at idle. You don’t need to know how many stages are in the low pressure compressor (six total, two fan and four compressor) to get the big picture of why you keep the power up on final. Knowing the big picture of how heavily loaded swept wings behave at high angles of attack will also give you a better understanding of why simply lowering the nose won’t immediately get you out of trouble (plus the delay in thrust buildup to further compound your woes). It is true that sticking to the book will ensure that you arrive safely, but it is better to understand both the concept and the details.

Pilots cannot and should not know it all. The FAA regulation to “Familiarize yourself with all available information concerning that flight” is a rule designed so that if a pilot makes any error that “reckless and careless” doesn’t cover, the book can still be thrown at them. Rest assured that if you put one into the ground a half-mile short, you’re getting blamed for not getting a weather briefing despite it being CAVU with calm winds, flying an aircraft with an inoperative ADF and for not knowing the airport manager’s office phone number . This is a poor way to ensure safety but a great way to have instant blame in the event of an incident. Instead of scaring pilots into trying to read everything to fit some liability model, we should be encouraging them to select the appropriate data for what they want to do.

We collectively have to accept that despite what we would like to have everyone believe, 99.2% of pilots will never know every single little detail about their airplane. This should be instilled in student pilots via the way they are taught. Start with the basics and allow them to get used to the 3rd dimension. Instead of filling their heads with regulations from day one, ease off and let them enjoy flying. Let them have a few hours of wrapping their heads around controlling the airplane before revealing that they’re going to have to become a lawyer as well to understand all the regulations. Instructors can easily move from the big picture of “Let’s do our maneuvers up high so if you make a mistake we have plenty of room.” to the verbatim description of FAR 91.303 over the course of their training. The rules will make more sense anyway if a little bit of experience and common sense are applied rather than “you need to know this for the test”.

As usual, I’m sure not many people will read this (especially this far down) and those that do think I’m either full of myself, dangerous, a crusader or a combination of the three. The truth is I love aviation but I’m also willing to point to where we can do a better job making it less daunting for newcomers to get involved, safer for those already flying and more enjoyable for everyone. If we are honest, it’s time to admit that the act of flying is not very difficult in execution. Judgment on the other hand is what kills people. Being able to recite regulations does not stop people from flying into IMC or descending below minimums. Only the proper attitude and respect for the fact that you’re suspended in the air by the laws of physics and aerodynamics will make a person accept their own limits and those of their aircraft. This must be stressed more than any chart, schematic or diagram.

BMI Tests For Pilots: Avoiding The Issue

(This article was originally published on my fitness site 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.


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 “Summary Of Pilot Medical Standards
February 26, 2007

The Case For Long Range Regional Jets

The Case For Long Range Regional Jets

A Practical Application


By Christopher Williams


The regional jet has become a dominant force in air travel in the last decade. While there are economic drawbacks to small jets on short routes, there are decided advantages on longer trips. Because of these advantages, it may be time to move towards long range regional jets. However, before an analysis of a long range regional jet is begun, it is necessary to examine why lower capacity makes sense in not only the traditional hub and spoke system, but in a direct flight system as well.

“Regional jet” is a fairly recent term for a fairly old concept. The Fokker 28 and McDonnell Douglas DC-9-10 would both fit into the category of regional jet (hereafter referred to as RJ) even though neither were consistently used in a manner congruent with current RJs. The modern class of RJs spans the gamut from the 50 seaters such as the Embraer ERJ-145 and Bombardier CRJ200, to the much larger 100 seaters like the Embraer E-190. They are generally powered by high bypass turbofans that have tremendous fuel consumption improvements over turbojets and low bypass turbofans that powered first-generation small jets. Due to their small size, they typically do not have multiple lavatories and baggage storage space is somewhat limited.

Larger airliners (often referred to as “mainline”) have the numbers advantage in terms of seat cost per mile, fuel consumed per seat per unit of distance, or any other statistic involving dividing a quantity by the number of seats. The more passengers that can be carried equates to a lower cost per passenger to operate the flight, which in theory should result in lower fares. RJs are at a disadvantage from the start due to their lower total capacity. Unless total operating costs are reduced by the same factor that the passenger capacity is, there will always be a disadvantage to operating with fewer total seats.

The disadvantage of larger airliners is their higher upfront purchase cost and their higher total operating cost. This is where RJs have the advantage from being smaller aircraft. The aviation consulting group Morten Beyer & Agnew refers to this as the “RJ Operating Cost Paradox”. Even though RJs cost less upfront to buy and less total per hour of operation, they still cost more per person and thus have a much smaller maximum profit margin. [1] This problem has led manufacturers to build larger RJs, like the aforementioned E-190 which boasts up to 114 seats and a breakeven capacity of 61%. [2]

But RJs are not the only aircraft that suffer from reduced capacity. The larger overall cost of operating a full size airliner at reduced capacity is even more of a problem for their operators, which is why so much effort is made to fill every seat on flights. It’s a lot like gambling. With small jets, you take a smaller investment and end up with a smaller return provided you fill your seats. With a big jet, you take a larger investment and end up with a much bigger return, again as long as the seats are filled. If the RJ doesn’t fill its seats, the total loss is still less than a larger jet in the same predicament. Win big, lose big.

Regional aircraft of varying sizes line up for takeoff at Denver International. Where mainline jets used to do more short to medium range trips, RJs have taken over the lions share of the workload.

How can it be possible combine the advantages of airliners and RJs? The answer may lie with what passengers want rather than what airlines want to give them. For an airline it makes financial sense to use the hub and spoke system to funnel passengers to a few mega-airports and then redistribute them to other smaller airports via RJ or commuter turboprop. For passengers it makes sense to go to an medium sized airport not too far from one’s home and fly direct to wherever they need to go. Unfortunately, unless people live near a large international airport, chances are good that they will have to switch planes at some point, even for a relatively simple trip between terminals of moderate size.

The hub and spoke system was first adapted to passenger aviation by Delta Air Lines in 1955 and later adapted to freight by Federal Express. [3] While this system works wonderfully for packages that have to arrive only by a certain time, say Monday at noon, it does not work well for passengers who want to get to their destination as soon as possible. A package does not care if it sits in a warehouse for 10 hours before being loaded onto a connecting flight to its destination. Passengers tend not to be as enthusiastic about such delays. Another reason for the popularity for hub and spoke had to do with the aerodynamics and performance of first and second-generation commercial jets. With their very high rates of fuel consumption at low altitudes, it was not wise to use them on short trips or at low altitudes. At the time, this had less to do with the price of fuel and more with getting useful range out of the aircraft. To fill the gap, turboprop commuter airliners were pressed into service to connect outlying airports to the major ones. While extremely efficient and fast, passengers still equated them with old lumbering piston airliners. Even though turboprops are technically jet engines with an exposed propeller instead of a shrouded fan, perceptions count for a lot.

RJs are jets through and through which makes passengers happy. But while pilots who may have upgraded from 4 and 6 seat general aviation or charter aircraft might think they’re big, the truth is many passengers still consider them small. And even though newer designs such as the CRJ900 are much larger than the original cadre of RJs, they still cannot compete with the sheer size of an Airbus A340, or Boeing 777. Size aside, the speed and ride quality are on par with small to medium sized airliners. Regional airlines and their supporting major airline counterparts could not buy enough RJs until the fuel crisis of the mid-2000s. At the point when fuel prices skyrocketed, the once beloved aircraft became very unattractive in the eyes of airline accountants. [4] Regional carriers wished for their fleets of turboprops back and many invested in newer designs like the Bombardier Q400 that rival jets with respect to ride quality and sound levels inside the cabin. On short trips, taxi, climb out, descent take up a major portion of a jet’s time and fuel. In some cases the actual time spent at cruise may be around 30 minutes, severely reducing whatever advantages the manufacturer may have designed into the airframe for that portion of flight. In a turboprop the maximum altitude is usually far lower, in addition to the fact that they use a lot less fuel at low altitudes making them more efficient on short trips.

Many people had assumed with the advance of RJs, so too would the ability to travel almost anywhere within reason in the United States without having to go through a hub airport. This never materialized and by 2007, flight delays had risen to a 13 year high as hundreds of RJs tried to occupy the same airspace and parking areas as hundreds of mainline jets. [5] By using RJs to fill in gaps in the hub and spoke system, airlines had unwittingly taken away the major advantage of low capacity jets and undermined their mainline fleets. With the lines blurred between RJ and mainline equipment, some low cost airlines such as JetBlue opted to use A320s for transcontinental and international routes and E-190s for shorter hauls. [6] Oddly enough, successful low cost carriers like JetBlue and Southwest Airlines fly on watered down versions of hub and spoke and use small airliners or RJs on all routes. It remains to be seen if current regional airlines will continue to serve as feeders for the majors or if they will venture off into the volatile world of low cost national operators. Major carriers, currently uninterested in their own RJ fleets, may change their position if that happens.

This next part of this paper will not deal with how to build such an aircraft in detail but will outline the criteria that will be required of the next generation of long range RJs.

Mainline jets, as mentioned, have a huge passenger advantage over RJs. This is also their Achilles heel if the flight is operating at reduced capacity. On red-eyes or on low demand long range routes, using a nearly empty Boeing 757 makes less economic sense than using a partly full Airbus A320. In that respect, using a partly full A320 would make less economic sense than using a nearly full long range RJ. For this to happen, the RJ would have to have transcontinental range with enough reserve to account for average yearly headwinds, missed approaches, a diversion to an alternate field in case of poor weather and any other situation that may stretch the endurance of the craft.

Airliners of all sizes only make money when they fly, and then only if paying passengers are riding inside. Empty seats do not make money which is why full airplanes equal happy shareholders. But passengers do require a bit more room and creature comforts than the average overnight parcel. It is for this reason that future RJs must have as much personal room as the smallest mainline jets. This will require advanced ergonomic design to ensure that the aircraft remains light enough to land at smaller airports, produces minimal drag in cruise but still allows people to stand up in the aisles or go to the bathroom without having to crouch. These same comfort features will be extremely important when considering that the next generation of RJ will have to be able to fly at least 2500nm, if not more.

Takeoff and landing are critical issues for any aircraft and commercial jets have a plethora of criteria to meet before every being certified to carry a single passenger. Airliners do not usually need an entire 10,000 foot runway to takeoff at normal weights, but the extra distance is required in case of an engine failure on takeoff. Below a certain speed (V1) the jet must be able to stop in the remaining runway. Above that speed the airplane must be able to accelerate to takeoff speed in the same remaining runway. For this reason, a Boeing 737 that might be able to become airborne in 3500 feet may require 7000 feet for regulations. This is the balanced field length that is listed as the takeoff distance for all commercial aircraft. Any reduction in takeoff velocity, any increase in acceleration or any combination thereof will go far in reducing balanced field length and thus open up whole new airport markets to airlines. This of course is if there is a demand for the service at those locations.

From takeoff to cruise the aircraft is in a climb. Usually this is not a constant uninterrupted climb as almost all airports have departure procedures (DPs) that require a pause in the ascent at certain points to help with traffic management. Once clear of the immediate area though, most jets are free to climb at their most efficient rate. A major problem for aircraft climbing has not been ability to climb, but excessive noise. Novel concepts for reducing power at strategic segments of the climb such as the Quiet Climb System by Boeing are aimed at making living near an airport quieter. [7] Another approach to the problem is to design aircraft with more excess thrust that allows for steeper climb angles that removes the source of the noise from the ground much faster. An added benefit for pilots and airlines is that the jet will arrive at cruise altitude sooner and begin its most efficient profile earlier in the trip. While excess thrust sounds wasteful, it is only used when required, thus allowing the engines to work at far lower power settings during normal phases of flight, prolonging their lifetimes.

Cruise speeds have been the same for almost all commercial airliners since the 1960s. RJs typically cruised slightly slower than their larger brethren. If the next generation of RJs cruised as fast as or slightly faster than mainline jets, a large advantage would be recognized when combined with the quick climb technique. Current state of the art includes winglets to increase effective aspect ratio of the wing, high bypass turbofans, vortex generators and laminar flow wing sections that all combine to reduce drag.

Descent in commercial aircraft is generally accomplished via flying a standard terminal arrival route (STAR) which is a series of waypoints and altitudes that aircraft follow to remain sequenced and separated on their way to a busy airport in all types of weather. An MIT led study using late night UPS flights into Louisville, KY helped develop the Continuous Descent Approach which saves fuel, time and reduces noise on the terminal approach phase of flight, which often begins over 80nm away. [8] Applying these techniques to an RJ that may even be capable of steeper descents simply means that the high speed cruise portion of flight can last longer and save even more fuel and time overall.

Finally, landing must meet other criteria much like the takeoff had to. Having a low approach speed, strong brakes, thrust reversers (very important on wet, slushy or icy runways as wheel brakes have reduced friction) and aerodynamic devices are all required to make the RJ land in a short distance consistently and safely. The latest in cockpit technology including heads up displays and velocity vector symbology will assist the pilots in using minimal power until the final portion of the approach and touching down exactly where they want to.

Even though flying is the glamorous part that everyone wants to talk about, no aircraft will fly unless it is serviced and repaired on a regular basis. An airplane that is a joy for pilots and passengers will be short lived with airline management if it consumes twice as much in maintenance costs as its contemporaries. Making it easy to work on is another very important aspect. Providing access panels, regardless of material used in construction of the aircraft is very important to maintenance personnel who may have limited time to get an aircraft turned around. Industry standards may apply here as most modern airliners have a 98% or higher dispatch reliability.

When one begins to think of RJs as actual airliners, possibilities for the restructuring of national routes begin to multiply. At this point, the advantages of point-to-point travel begin to make sense and airlines will have the freedom to place their fleet strategically at places that have the demand. If there are seasonal changes, the RJ can much more readily deal with the increase in demand, which may not be enough to warrant using a larger aircraft. It may become possible to fly from a low traffic airport such as Atlantic City, NJ directly to another low traffic airport such as Lansing, MI. How many people actually need to travel to certain city pairs will dictate how often the jets are used. In some cases it may be a once or twice weekly service. In others it may be multiple daily flights. Regardless, the longer segments of the new RJs will make it more economical to use even with a lower total passenger load.

But despite point-to-point being an intriguing idea for travelers, it is not likely that airlines will change their entire route structure overnight. It is therefore important that the new RJs can operate within the current hub and spoke system efficiently as well. This is perfectly feasible provided they are used for the segments that require them. For 65 people who need to travel 1000nm from a hub to an outlying city, they really are not concerned if their airplane is a Boeing 737-800, an Airbus A320 or a CRJ900. What matters to them is that they have practical options for departure and arrival times, that the aircraft is comfortable enough for the stage length and that the aircraft is safe. For pilots what matters is an aircraft that has enough performance to fly the assigned trips without undue effort, that its systems are intuitive and that it is safe. And of course airline managers want it to be inexpensive to purchase, operate and maintain. Having passengers, pilots and maintainers like it only helps to increase the overall value of the purchase.

The maturation of the RJ into an aircraft that is respected and loved by pilots, passengers and airlines is currently taking place. New procedures will have to be developed, new routes will emerge, and new pay scales will have to be developed as airlines integrate long haul RJs into their fleets of mainline jets. Pilots need not look at future RJs as almost-airliners or little airplanes. They will still carry passengers at a significant fraction of the speed of sound several miles above the earth. For those who enjoy flying but wish to spend more time at home with family, flying RJs can offer an attractive option to flying longer international routes. But crew pay must be fair in order to ensure the same caliber of pilot who is flying the Boeing 747-400 over the Pacific is flying the advanced RJ over the Midwest. Murphy’s Law does not care how big an airplane is and sharp individuals are required for all airframes. US Airways flight 1549 (Miracle On The Hudson) is perfect evidence of that.

In today’s economy it has become necessary to rethink everything. That includes how flights are planned, how aircraft are used, how we define what is major, what is national, and what is regional. But it should be remembered that classifications matter not, in the end only the efficient survive. 

As Bombardier CRJs line up at Philadelphia International, a Boeing 737 taxies past. Perhaps the future of commercial air travel lies in integration for maximum profit and passenger satisfaction.

Works Cited

1. Beyer, Morten & Agnew, Robert. “Morgan Stanley Conference-Regional Jet Update”

2. “Embraer 190 Specifications”:

3. “Delta Through The Decades.” Retrieved: Feb 6, 2010

4. Bachman, Justin. “Airlines Give Propellers Another Spin.” BusinessWeek, April 30 2008

5. Zibel, Alan. “Flight Delays Soar To 13 Year High.” The Washington Post, August 7, 2007

6. “JetBlue and Southwest Airlines Destination Maps”: : Retrieved Feb 6, 2010

7. Friedrich, Jerry; McGregor, Daniel; Weigold, Douglas. “Quiet Climb System”. Aero, First quarter 2003:

8. Walton, Jim. “Continuous Descent Arrivals.” 2005 Boeing Performance & Flight Operations Engineering Conference: