Staying Alive in Small Airplanes

One of the hazards of wealth and/or hanging around with rich people is the possibility of dying in a small airplane crash.  If you’re an average schmoe you’ll wear a rut in the pavement between house and job, be entertained watching TV on the sofa, watch your kids get on the schoolbus every day, and drop dead of obesity [should say “average American”, I guess] at age 83.4.  The rich, however, must shuttle among their 5 luxury homes and get their kids to and from exclusive private schools in the countryside.  Shuttling requires many private airplane flights, not least because the luxury homes may be on islands where airplanes provide the only access.  If you want to escape the rabble you have to go somewhere that is impractical to read by car and that isn’t so populated that it merits daily Boeing 747 flights.


A couple of recent airplane crashes, however, have got people scared.  One involved Minnesota Senator Paul Wellstone and an April 4 crash here in Massachusetts involved M. Anthony Fisher, a real estate tycoon from New York.  Both were in Beech King Air airplanes, each of which had two engines and two professional pilots.  Both were doing non-precision instrument approaches in bad weather.  In both cases people initially suspected icing, a terrifying flight hazard in cold-weather clouds but one that the King Airs are reasonably well-equipped to handle.  In both cases the actual cause appears to have been that the airplane was simply flown too slowly and fell out of the sky, which is by far the most common way to crash an airplane for all levels of pilot.  People fear engine failure but they die from pulling the stick back too far.


Let’s start by looking at the most recent crash, which involved Bob Monaco, a pilot based from our local airport (Hanscom Field in Bedford, Massachusetts, BED).  Today’s Boston Globe carries a story that is typical for (a) being filled with errors, and (b) not providing the URL where readers could find the original National Transportation Safety Board report and study it themselves.


The goal of the trip was to fly the rich family up to a prep school that the daughter was considering attending, then take the rest of the family and its interior designers out to their house on Martha’s Vineyard.  The pilot, Bob Monaco, planned the flight initially from New York to Bedford, a large civil/military airport with a 7000-foot main runway and an instrument landing system (ILS). 


Background on aerodynamics:  Airplanes hold themselves up by pushing air down.  In flight, an airplane’s wings are angled up. As the plane moves forward this angled surface pushes air downward and, as a reaction, the airplane rises up (Newton’s 3rd Law). Air weighs a lot less than the metals and plastics in the airplane and therefore one must push a lot of air down in order to pull the plane up, which is why wings are so physically large.  An airplane must maintain a reasonably high forward speed for the wing to do its job; a wing that isn’t moving pushes no air down.  If a pilot, in attempting to slow down for landing, slows down too much the plane will “stall” and become hard to control.  If the pilot does not immediately push the stick forward to pitch the airplane down and pick up more speed, the plane may go into a “spin” and start to fall out of the sky.  A plane can be recovered from a spin but usually this requires more altitude than is available if the spin happens while approaching to land.  Turning an airplane uses up lift that would otherwise be available to hold altitude and therefore an airspeed that works for level flight will result in a stall in a tight turn.


Background on flying in the clouds:  An ILS approach is referred to as a “precision approach”.  Under normal circumstances the Air Traffic Controllers (ATC) give you radar vectors and altitudes to fly until you intercept the radio beams of the ILS.  They are required by regulation to set you up so that you need not make more than a 30-degree turn to get onto the ILS, i.e., ATC points your airplane more or less straight in toward the landing runway.  Once established on the ILS you make very small adjustments in pitch and bank to keep the needles centered and set the engine power so that your airplane holds a slow steady speed (pointing the nose down toward the ground would normally build up a lot of speed so you cut engine power from its cruise setting to reduce the total amount of energy being put into the system).  Notice that at no time on an ILS is the airplane required to make a turn; the airplane is going slow but flying straight.


At Bedford the ILS 29 approach lets you go down to 300′ above the ground without seeing anything, then, if you can see the runway lights you’re allowed to go down until you’re just 100′ above the ground.  In an emergency you wouldn’t worry about ever seeing the runway but keep flying the needles until the wheels slammed down on the pavement (they do this in training in Europe, actually).


Not only does an ILS provide low minimums but it also generally comes with assistance from ATC.  If you’ve somehow gotten very confused or your equipment isn’t working right and you’re off-course or at the wrong altitude, they’ll probably call you on the radio (they are invariably polite and ask you to “say altitude” or “say position”, hoping that you’ll discover your mistake, rather than “you’re in the wrong place, bozo”).


A non-precision approach is a much more complex procedure that (a) requires a bunch of turns in the clouds, fairly slow and low to the ground, (b) makes the pilot(s) solely responsible for the airplane’s position, and (c) requires the airplane to stay at a higher altitude if the pilot cannot see the runway.


Why would you ever do a non-precision approach?  For the airlines the answer is generally that you don’t.  You fly from ILS-equipped airport to ILS-equipped airport.  If there is no ILS at an airport that you wish to serve, you twist the government’s arm into installing one.


On April 4, Bob Monaco changed his plan, while in flight, to go from an ILS-equipped airport (BED) to a much smaller airport, Fitchburg (FIT) at which only non-precision approaches are available.  Because he is dead we can’t ask him why but we can presume that he got a weather report for FIT that said the clouds weren’t that low and FIT was closer to the prep school, thus saving 45 minutes of driving.


From the NTSB report, it sounds as though the clouds were right around 1000′ above ground level, which is the minimum height that Monaco was required to maintain above the runway until he could see it.  It sounds from the witness reports that he did not really see the runway until he was right on top of it.  At this point he was too high to land.  However, it is legal, assuming that you can maintain continuous visual contact with the runway, to make tight circles around the airport and then land, perhaps on a different runway than the one you were initially approaching.  You want the circles tight so that you don’t risk flying into more clouds.  Note that tight circles imply turns and that if you are hoping to land an airplane you want to be going slowly.  Recall from the aerodynamics paragraph above that turning makes it more likely that the airplane will stall at a given speed.


Even with two pilots on board, the challenge of keeping the runway in sight, setting the plane up for landing, and making those tight turns was apparently too great and the King Air crashed.  The NTSB report says that the airspeed indicators showed 60 and 66 knots on impact, which is a good speed for a little training airplane but much too slow for a King Air in a turn (the King Air’s typical approach speed is 100 knots).


If you’re planning to take a trip in a small airplane, what lessons can you learn from these mournful events?  First, legal does not equal safe.  One reason that the airlines have such a good safety record is that they are much more conservative than required.  For example, many airlines have found that their pilots are unable to maintain acceptable tolerances during circling-to-land approaches such as the one Bob Monaco was attempting and therefore they no longer train pilots on this procedure nor use it in operations.  Second, an ILS greatly enhances safety.  If the weather is marginal and your friend says “we’re going to the little airport at Gaithersburg, Maryland” repond with “I don’t mind driving an extra 20 minutes from Dulles or Baltimore-Washington International”.  Third, if you really want to be safe wait for the weather to improve.  Even with the best equipment and pilots, sunshine adds a big safety margin.

13 thoughts on “Staying Alive in Small Airplanes

  1. There was a recent small plane crash in the Rochester, NY area (see http://www.democratandchronicle.com/news/0415story5_news.shtml). This one was not during a takeoff/landing and wasn’t observed. It was a club-owned plane and a pilot/instructor was supposedly evaluating two other pilots to certify them to fly the plane. They know where everyone was sitting at the time of the crash but because the plane had two sets of controls it’s not known who was actually in control at the time of the crash. The article talks about them finding a handheld GPS device that may offer some clues but only if it has a recording feature. I’m not familiar with GPS devices, is this a common feature? I can imagine they might be able to tell the flight path but could it also give airspeed and altitude?

  2. Last time I looked at a textbook, let’s say oh, 20 years ago, they claimed that airplanes generated lift via the Bernoulli effect. That is, the rounded upper surface of the wing increases the airspeed over the wing, thereby lowering the pressure, thereby creating a vacuum over the wing that gave lift. This always seemed somewhat hard to believe, since a flat piece of wood will generate lift, as long as the angle of attack is greater than zero. Is it now generally accepted that lift is generated from pushing air downwards, through angle of attack of the wing, rather than Bernoulli effect? Or is this horribly inefficient, and planes really do use the Bernoulli effect to keep flying? Inquiring minds want to know…

  3. Tom: I think some of the newer handheld GPS units do record flight path and ground speed and from that you might be able to infer airspeed if you knew the winds. I don’t believe, however, that the $15,000 panel-mounted Garmins in my airplane keep any kind of history, though. Microsoft Flight Simulator does!

    Gregory: the problem with the Bernoulli/asymmetric airfoil explanation is that it doesn’t seem to explain how an aerobatic airplane can fly upside-down. The Bernoulli effect way of looking at aerodynamics isn’t wrong but it isn’t very good for developing an intuitive understanding.

  4. Philip, You might want to clarify whether your condemnation is for all non-precision approaches or just the circle-to-land maneuver? Sure, I love an easy ILS (particularly with my GNS430 coupled to the S-Tec 60-2 autopilot through my GPSS interface), but my home field only has a GPS approach due to terrain. No ILS. I don’t consider that non-precision approach to be significantly more dangerous than the ILS at a nearby airport, >>>so long as I can land straight in -OR- the ceilings are such that I have to maneuver at less than VFR pattern altitude.<<< To my mind, there’s a discontinuity in the risk curve if I have to perform a circle-to-land at low altitude, but not just because the approach isn’t an ILS. And don’t forget that there are cirlce-to-land terminations for most ILSs as well, and those are (in my mind) even more dangerous, since they can often be done at even lower AGL altitudes.

    The only time I’ve scared myself on an approach was on a straight-in ILS to minimums where I got distracted and lost the localizer needle completely at minimums. The first thing I saw through the fog was a hangar at 12 o’clock. Oops!

  5. Philip,

    Many handheld GPS units store track information, but I have yet to see an IFR certified panel mounted GPS store that information.

  6. Hallo from Germany, Philip.

    Thankyou for an article well written and understandable to the layman.

    I’ve been teaching people to fly for over 20 years. Despite all modern technology, ILS,GPS, whatever, it is still pilot-error that kills the most.
    And going-too-slow is the major one. Continued-flight-in-bad-weather is major for VFR pilots, some of whom RELY on a GPS they can barely interpret, in really marginal scud-running conditions.
    Generally, the killer-disease is known here as “Get-Home-itis” 🙁

    Stu Savory, CFII

  7. Doug: You’re probably a more experienced pilot than I, so I’m not going to presume to preach to you. But personally I limit myself to ILS approaches if the weather is remotely bad because I want the extra layer of redundancy afforded by ATC. If I were up in Alaska and the nearest ILS were 2 hours away and the ceiling was 1000′ I’d probably do the non-precision approach. But here in the crowded Northeast there is almost always an ILS within a 30-minute drive from my destination.

  8. Civil aviation grew up on non-precision approaches but I believe most pilots fail to practise the circle-to-land maneuver that accompanies nearly every one of those approaches. The mental shift required to transition from inside the cockpit flying instruments to outside the cockpit flying visual references is challenging. Add to that challenge the probability that clouds are possibly wispy and you have the prospect of a pilot flying too low for a normal contact traffic pattern. In those conditions, some people try pylon turns. But low-level acrobatics don’t always result in smooth landings when part of this kind of a mix. That’s my experience over 3000 flying hours on six continents.

  9. Gregory: I’m not a pilot, but a former Air Force weather officer. We weather guys get exposed to a lot of trivia. Airplanes use two mechanisms to fly: (1) Bernoulli effect from the asymmetric wing and (2) Angle of attack. Different airplanes use these two mechanisms in differing degrees due to the design constraints of each aircraft and whatever the pilot is attempting (e.g., inverted flight). For example, a T-38 trainer (and presumably the F-5 figher equivalent of the same craft) has an extremely tiny and absolutely symmetric wing. It’s mounted on an axle so that the pilot can angle it up or down at will. This airplane flies completely on brute force, with no appeal to Bernoulli!

  10. A great item on flying safety! It doesn’t motivate my IFR training, but it sure accentuates the factors of weather, flying physics, and critical transitions between visual and instruments. I would propose that going to bigger or better airports gets dangerously close to suggesting that wealthy people fly commercial airlines when the weather is bad! 😉

    The comments on aerodynamics are interesting. The lift controversy marches on, thanks to our education system. I always give credit to Kutta, and a nice sharp trailing edge on the wing. Bernoulli is a minor-league guy who got the press.

  11. A few brief comments from an aerospace engineer:
    1. The lift is produced by Bernoulli’s Law (total pressure (dynamic + static) remaining roughly constant), not Newton’s Third Law (action & reaction, how rockets work), which is a common misperception, and results from the differences in pressures between the upper (faster-flowing & so lesser static pressure) surface and the lower.
    2. The wing (airfoil) can be either symmetric or asymmetric (cambered). The flow changes based on angle of attack.
    3. The lift required increases in a turn based on the reciprocal of the cosine of the bank angle (e.g. 2 g’s are pulled at 60 degrees bank).
    4. The FAA recently announced a program to (eventually) replace many non-precision approaches with “virtual” (so to speak) ILS approaches. Hopefully this will progress faster than many of the FAA’s other projects have.

  12. The article on the small airplanes, personally is upsetting. I am no pilot, and I happen to stumble upon this article. However, i knew the people on that plane as I am a family member…and what you wrote was rude. You didn’t know these “rich” people and how charitable they were. The “tycoon” you speak of was a silent donater and a silent hero. If you did your research you would find that he was honored in the base of the Intrepid Sea Air Space Museum by thousands. I hope that you realize he was taking his daughter to the same highschool he went to, and she was very excited to be going there. The daughter, who survived if you researched this crash, also has read this article and was very disturbed by your assumptians about her lifestyle. The plane happened to be a friend’s that was offered as a ride because it was convenient. That event was life altering for that girl, and I hope you are happy with your analysis of rich people and your stereo-type. Bob, the pilot also happened to be a great guy, so maybe you should reconsider what you type and keep it on a professional analysis!

  13. Gordon: Can you elaborate on what causes the air to go faster along the upper surface of the wing rather than the bottom? The explanation I usually hear that the air travelling along the top must move faster in order to meet the air travelling along the bottom doesn’t sound convincing. (why should the two arrive at the trailing edge of the wing at them same time?) If the story is too long, can you give a reference?
    Eugene

Comments are closed.