Sunday,
May 20, 2007 Vol. IV No.
10 |
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Welcome
to the
Over the
Airwaves
aviation journal. This complimentary bi-weekly e-mailing
is being sent to pilots and aviation enthusiasts around the
world. Its aim
is to promote
flight safety, encourage students and new pilots, and to build
enthusiasm for aviation in general.
Keeping It Simple
The challenges of safely flying an airplane are sometimes too great for some people to master. Complex avionics, unstable aircraft, poor weather, complicated airspace, illogical instrument procedures, and short runways can easily compromise the efforts of even the most proficient pilot. Curiously, there are other flying tasks that exceed the capability of a surprising number of pilots. One such task requires us to insure we have gas in the tanks before launching. Another is looking out the window. Remaining clear of challenging weather is another big one. Then there is the matter of avoiding stall/spins. These are simple tasks, yet the accident data reveal that fuel factors, mid-air collision, controlled flight into terrain (CFIT), VFR flight into IFR conditions, and stall/spins are what kills most pilots.
Then there was a 96 hour non-instrument rated Cessna 150 pilot who, with a friend, took off this past September from an airport in Virginia in instrument conditions hoping to reach clear skies above. His last recorded radio transmission was, "We're kinda lost in some fog here . . . I think we're upside-down. . . We can't see, we can't see, we can't see." Both are now dead. (NTSB Report).
They were part of a flight of two helicopters traveling from Pearson Field Airport, Vancouver, Washington, to Astoria, Oregon. VFR prevailed at the departure airport and IFR conditions were reported along their route of flight. Because of the worsening weather, the pilots elected to scud run over open water. Their plan didn't work. The Robinson R22 pilot radioed to the other helicopter and said, "Go back up... it's too low. It's much lower than we thought. Go back up right now." The Jet Ranger helicopter pilot replied, "I'm going to go through it . . .stay right behind me." Approximately 15 minutes later, two orange life vests and miscellaneous wreckage debris were found floating in the water approximately one mile offshore. All three aboard died in the crash. The NTSB ruled that the probable accident cause was the pilot's intentional flight into instrument meteorological conditions while maneuvering which resulted in an in flight collision with terrain/water (NTSB Report). Keeping it simple . . . Curiously, it is not the complex things that cause us harm in airplanes. Nor is it our lack of basic maneuvering skills or mechanical failures in our airplane that get us. Instead, it's the simple things that kill us. As the above three fatal accident scenarios reveal, we pilots occasionally fail at the really simple things . . . like fueling the airplane, or remaining clear of IMC weather, or by scud running to avoid the clouds. Several days ago, a Beech Baron 55 (twin) pilot, with two passengers aboard, encountered a rough running engine near my home airport. He shut it down. ATC steered him to Dunkirk, the nearest airport which, at the time, happened to be at IFR minimums. Rather than flying on one engine another 40 miles to excellent VFR conditions and the long and wide runways at the Buffalo/Niagara International Airport, he elected to shoot the Dunkirk VOR/GPS Runway 24 approach to minimums. Not stabilized on the approach, he executed a missed approach with flaps and gear still down . . . with fatal consequences. All three people perished. There is, indeed, something wrong with this picture. No, we humans
are not perfect. Bad things do happen to good
people. But if we could
eliminate the simple mistakes, the complex ones will
take care of themselves. Bob
Miller, ATP, CFII Be Careful in those Turns ! !
When done in the traffic pattern in a normal category airplane, especially when operating above maximum allowable weight, can be disastrous. The simple banking of an airplane in coordinated, level flight produces two potentially BAD events as follows:
A quick reference to the graph below illustrates that when bank angle in coordinated level flight increases to 60 degrees, the load factor or G loading doubles. Thus, each 180 pound occupant in a 60 degree bank weighs 360 pounds! Similarly, an airplane at maximum gross weight of 2,400 pounds weighs 4,800 pounds in the same 60 degree bank. Banking another 10 degrees to 70 degrees creates a load factor of nearly 3 (3Gs). Our 180 pound passenger now weighs a whopping 540 pounds!
2- Stall Speed Increases The second potentially bad event resulting from steep bank turns is an increase in stall speed. Remember, stall speed increases in proportion to the square root of the load factor. A 60 degree level turn bank produces a load factor of approximately 2Gs. The square root of 2 is 1.4. Multiply a normal stall speed of, say 40 knots, by 1.4 produces a new stall speed of 56 knots when in a 60 degree bank. Our normal 40 knot stall speed increases to 78 knots when in a 75 degree bank! Yanking and banking can be fun in an aerobatic airplane. In an airplane certified in the normal category, yanking and banking can be hazardous to your health. Thanks to OTA contributor Thom Riddle for preparing the graph used in this article. Duh? Is there Fuel in the Airplane?
Guilty on both counts! That's how the NTSB ruled on a fatal accident that occurred this past November near Sanderson Field (SHN) in Shelton, Washington. Here are the facts . . . Witnesses observed the pilot of Beech D35 completing his run-up at the departure end of Sanderson Field's Runway 23. He taxied on to the runway and proceeded down the runway in what appeared to be a normal takeoff.
Witnesses reported seeing the airplane making a slow descent back to Runway 05. "It then pitched up, followed by the right wing dropping," added another witness. The CFI said he continued to watch the airplane descend until it disappeared behind a stand of trees. Another witness said that he saw an aircraft crash west of Runway 05. The first responders to the accident site found the airplane in a near vertical nose down position. The witness further stated that there was no overwhelming smell of fuel, nor was there any fuel observed leaking from the airplane. There was no post-accident fire.
So what when wrong? It doesn't take much imagination to figure what happened here. The accident airplane contained just enough fuel to taxi, takeoff, and climb for about three minutes before the engine quit. Is there any plausible reason why this could have occurred? Did the pilot not eyeball each tank during his preflight inspection? Was he depending upon his fuel gauges exclusively for fuel quantity information? Did he mis-calculate his fuel burn during his last previous flights in that airplane? Short answer . . . he took off with near-empty fuel tanks! There cannot be any justifiable reason for doing this. But why did he have to die? Okay, fuel exhaustion results in engine failure. The airplane is still an airplane and it still has wings, altitude, and airspeed. The failed engine merely converts the airplane to a glider, albeit somewhat heavier than conventional gliders.
Instead, had he simply pitched his airplane for best glide rate, he would have likely settled into the trees rather than boring a fatal hole in ground. While tree landings are not predictable in their outcome, they do offer a far greater margin of safety than stall/spin events close to the ground. Message to Spin Training Opponents . . . Flight attitudes required to produce a stall/spin event are well recognized by folks who have had a reasonable level of stall/spin training. Had this pilot received such training, my guess is that he would be with us today. Seriously Short Field . . .
There are two ways to produce longer runways. One, of course, is to pour more concrete. The other is to master our short field takeoff technique! Mastering short field operations first requires that we understand the aerodynamics of lift and drag. We know, for example, that parasitic (form) drag increases as speed increases. Conversely, induced (lift) drag increases at low speeds. Removing unnecessary induced drag . . . Our goal in short field operations is to eliminate induced drag during the takeoff roll. We do this by keeping the airplane on the runway until reaching Vx (best angle) climb speed. With no resultant lift on the takeoff roll until reaching Vx speed, there can be no induced drag. It
should be remembered, however, that some airplanes will have
a natural tendency to lift off well before reaching Vx.
In these airplanes, it may be necessary to allow the
airplane to lift off in ground effect and then reduce
This method is preferable to forcing the airplane to remain on the ground with forward elevator pressure until best angle-of-climb speed is attained. Holding the airplane on the ground unnecessarily puts excessive pressure on the nosewheel, may result in “wheelbarrowing,” and will hinder both acceleration and overall airplane performance.
In summary, to achieve optimal short field proficiency, we must exercise positive and precise control of airplane attitude and airspeed so that takeoff and climb performance results in the shortest ground roll and the steepest angle of climb! As in all flight operations, a careful study of Vx and Vy speeds published in the POH should be made before commencing short field takeoffs. Who's on First??? Okay, so operating around large, Class B airports is not for every GA pilot, but for those who do, paying close attention to harried ground controllers is the key to finding your way to the ramp. Click HERE to listen to an entertaining recording of a KJFK "take no prisoners" ground controller as he exhibits his frustration while maintaining law and order in this highly stressful airport environment. As you listen, come back to the KJFK airport diagram below and imagine yourself trying to find the GA terminal.
Be a Good GA Citizen . . . As you heard in this recording, the airline guys are good. Each pilot obediently complied with the controller's instructions. We can imagine how this controller would have handled a less than proficient Bonanza and Cirrus SR22 pilot! If we GA pilots are to continue operating at large airports and in busy airspace, we owe it to the "system" to be on our game. If we're not, we need to either remain clear of these areas OR we need to become proficient!
Congestion over the Airport Any pilot with a morbid interest in INCREASING the risks of aviation should spend his or her time flying around the local airport traffic pattern! More mid-air collisions occur in and around the airport traffic pattern than in any other place in skies.
Curiously, we GA pilots likely spend more time in airport traffic patterns than in any other phase of flight, yet many of us are clueless of the finer aspects of proper traffic pattern procedures! One reason for our lack of traffic pattern proficiency is the paucity of instruction or guidance given us in the FAR/AIM. Another reason is that many pilots receive their preponderance of training at tower controlled airports where controllers direct us into and around the pattern. Lastly, local airport traffic pattern customs differ widely among airports. What may be acceptable at one airport may cause serious disruption or hazard at another airport. So what is the proper traffic pattern procedure? There are lots of factors to consider when entering and operating in the local airport traffic pattern. There are a couple of principles that are sacrosanct as noted below:
Generally between 800' and 1,000' AGL, the TPA is critical. Aircraft entering and operating in the traffic pattern should remain at the traffic pattern altitude. Climbing or descending into the traffic pattern is not only bad form, it is also dangerous. 2. Traffic pattern entries: As the illustration above shows, there are a variety of ways to enter the traffic pattern. The important thing is that we coordinate our entry with other traffic already in the pattern. A 45 degree entry to the downwind leg works just as well as base entry or straight in approach as long as we remain vigilant of all other traffic in the pattern. A word about straight in approaches: Straight in approaches are legal! In fact, straight in approaches offer the benefit of minimizing our exposure or time in the traffic pattern. The key, of course, is not to cut off traffic turning base and final when making a straight in approach. 3. Traffic pattern size: Each leg of the traffic pattern should be kept within 1/4 to 1/2 mile of the landing runway. Flying super-large, airliner-type traffic patterns creates both unnecessary delays and risks. For example, turning on crosswind or base leg when a mile or more from the runway causes everybody else to follow in trail. In time, the pattern becomes larger than the county the airport is situated in! Thus, the chance of seeing others in the pattern become increasingly remote. In summary, the most important consideration in the traffic pattern is to see and avoid other traffic. Good traffic pattern habits makes this all possible! Reminder - Wake Turbulence is REAL!
Anybody who operates around heavy transport category airplanes is well aware of the hazards of wake turbulence. For the uninitiated, however, the experience can be one they will never forget . . . if they survive! Wake turbulence is simply the wake created by an aircraft as it moves through the air. As with boats on a lake, the size of wake and the damage it can cause varies widely. Wake turbulence is caused by the pressure differential of air above and below the wing as an airplane is developing lift. This pressure differential triggers a rollup of the airflow aft of the wing resulting in swirling air masses trailing downstream of the wingtips. After the rollup is completed, the wake consists of two counter-rotating cylindrical wingtip vortices. Vortices are generated from the moment an aircraft leaves the ground, since trailing vortices are the byproduct of wing lift. The vortex circulation is outward, upward, and around the wingtips when viewed from either ahead or behind the aircraft. Tests have shown that vortices remain spaced a bit less than a wingspan apart, drifting with the wind, at altitudes greater than a wingspan from the ground. Tests have also shown that the vortices sink at a rate of several hundred feet per minute, slowing their descent and diminishing in strength with time and distance behind the generating aircraft.
Defensive Wake Turbulence Strategies . . . The most basic wake turbulence defense is to "take off before the rotation point and land after the the landing point of the aircraft in front of you." This practice should keep us clear of any wake turbulence by departing or arriving aircraft.
The Magnetic Compass - The Patron Saint of Reliability! The magnetic compass . . . it has been with us for centuries. In fact, the first recorded navigational use of a magnetic compass took place between 1405 and 1433AD when the Chinese sailor, Zheng He, used it during his seven ocean voyages. Since those early years, the magnetic compass has found its way to every ship at sea and to every aircraft aloft including the space shuttle. It is, in fact, the most reliable instrument on the panel.
The use of the magnetic compass is not without its predictable quirks. We know, for example, that magnetic compasses have two uniquely bad characteristics as follows:
Not only does the magnetic compass provide us with course guidance, it can also be used as a basic attitude instrument should our gyro instruments fail. If the compass is not showing a turn, our wings have to be level! Knowing this can save the day when everything else fails! "Stupid is what stupid does!"
Take, for example, the CFI and pilot of a Pilatus PC-12/47 who were practicing simulated engine failures on takeoff from the Big Timber Airport, Big Timber, Montana.What happened . . . According to witnesses, "The aircraft began to increase its climb and simultaneously bank hard to the right with the nose up approximately 30 degrees while in the turn." "The turn appeared to be uncoordinated, and the aircraft rolled to the right, as the right wing dipped aggressively. The nose of the aircraft yawed down to nearly -45 degrees, and while losing altitude the aircraft began to roll level but was still pitched down at a steep angle and accelerating." Another witness said, "The aircraft seemed to be recovering, but the elevation of the adjacent ridge was rising rapidly in relation to the aircraft's direction. At the last few seconds, the aircraft was able to pitch up in what appeared to be a landing flare." He said that he saw
dirt and grass flying up behind the aircraft just prior to
the airplane's right wing tip and engine impacting terrain.
Post impact fire consumed the airplane.
How many lessons must we learn? CFIs seem to have a morbid fascination with engine failures on takeoff. They gain great delight in simulating this scenario by pulling power shortly after takeoff, then tasking the hapless student to execute a low altitude 180 degree (actually a 270 degree) return to the airport. As in this fatal accident case, the results are not always as intended. The airplane generally stalls, then spins into an unrecoverable flight attitude. Needless training accidents of this kind need never occur if they were practiced at a safe altitude! Proficient pilots need to practice the many possible accident scenarios that can beset us. Realism is important, but not at the risk of closing all possible back doors. Donations needed to spread the OTA flight safety message around the globe!! If you found Over the Airwaves helpful to you personally and/or beneficial to general aviation and would like to support its continued publication, please consider making a donation to the effort. Simply click on the button below to access a secure link through which donations can be made. Your donations are used exclusively in the preparation, advancement, and promotion of Over the Airwaves to and for pilots all over the globe.
Aviation, perhaps more than any other endeavor, is filled with ponderous questions. There is one question, however, that nobody can answer. That question is, "Where do you draw the line between conservative and bold flying behavior?"
We can sit around the coffee pot at the local aerodrome and listen to old timers expound what they would or would not do in a given situation. Flight instructors are particularly good at setting the parameters for safe flight. But none of this dialogue answers the simple question, "Where do you draw the line between conservative and bold flying behavior?" The reason is, the answer cannot be generalized. There are simply too many variables. Defining that line for ourselves . . . While it is not possible to define the line between conservative and bold flying behavior for all pilots, we can certainly mark that line in the sand for ourselves. We should know, for example, what surface wind direction and speed limitations we can impose upon ourselves when contemplating a flight. But how do we come to that wind direction and speed limitation number? Do we pick that number randomly or is it based upon an actual experience factor? Does it come out of the pilot's operating handbook (POH) or is it based upon an externally imposed restriction from our CFI or flight school? New instrument pilots often set personal ceiling and visibility minimums for themselves. Again, how are these limits established? What objective basis do they use to arrive at these numbers? Experience determines the line ! Our actual flight experience tells us where to draw the line between conservative and bold flying behavior. This presumes, of course, that we properly evaluate our flight experience and that we learn from our mistakes. Thus, the more flight experience we log and, yes - the more mistakes we make, the better we are able to draw that line. The trick in all of this, of course, is to survive all of our mistakes so that we can actually draw that line! There are two ways to build flight experience. One way is to fly frequently. Get into the national airspace system and fly every day or least every week. Volunteer as an Angle Flight pilot; take lots of trips to distant cities; fly traffic spotters for a local radio station; sign on with a local Part 135 operator; attend lots of fly-in breakfasts. Whatever!
VFR only pilots . . . the absolutely BEST thing you can do is pursue your instrument rating. Even if you never envision yourself flying in hard IFR conditions down to minimums in your bugmasher, the training alone will make you a far more proficient pilot. Want to fly more gracefully? Mastering chandelles, lazy-8s, and 8s on pylons with the ball centered will do the trick (commercial certificate). In summary, developing pilot proficiency is much like physical fitness and muscle building. We have to get in the gym and stretch our flying muscles. Sure, we'll endure a period of soreness and an occasional muscle strain. But in the end, we'll be both stronger and more capable of handling all of the challenges of flight. A
word about costs. Sure . . . flying is expensive.
Engaging in recurrent training is even more expensive.
Achieving proficiency in any endeavor is expensive.
But for comparative purposes, consider the cost on
non-proficiency, particularly in airplanes! Fly safe,
Bob
Miller, ATP, CFII Upcoming!!!!!! Monday, May 28th: Memorial Day Fly-In Pancake Breakfast Akron (NY) Airport (9G3)
Airplane Rides $10 STATIC DISPLAYS Note: No aircraft departures between 0900 and 1000 hours to avoid interference with local Memorial Day Ceremony. Saturday, June 2nd:
AOPA Fly-In & Open House
AOPA Headquarters More information - Click HERE. Friday - Sunday, June 1-3:
17th Annual World War II Weekend Reading, PA For more information, click HERE. Supporting Sponsors
APS Emergency Maneuver Training specializes in upset recovery training, stall/spin awareness, aerobatics and spin recovery training.
Comments, Please! Over the Airwaves is not intended to be your typical training, official news, or club-type social journal. Instead, its intent is to stimulate thought, enhance aviation critical thinking skills, to encourage the strong pilot, and to disturb the weaker pilot. With this breadth of scope, Over the Airwaves will evoke a number of reactions. Please feel free to share these reactions with me by clicking HERE.
 Click HERE to open any previous issue(s) of Over the Airwaves and to search for any past articles.Technical Assistance I would like to thank the following technical assistance contributors for their valuable help in producing OTA every two weeks: Cameron Dunlop, Corning, NY; Barry McCollom, Kerrville, TX; Thom Riddle, Buffalo, NY; and Jay Rolls, Macon, GA. Globe and aircraft logo in top banner designed by Ulla Taylor Pavement Artist.
©2007 Over the Airwaves, Buffalo, New York, USA. |
Take
the case of a Beech D35
pilot operating near Sanderson Field (SHN) in Shelton,
Washington this past November. It seems that he
forgot to check the fuel before launching. Witnesses observed the airplane
in a steep spiral before impacting trees in a nose down
attitude. 
Lastly,
let's review the wisdom of two instrument rated
helicopter pilots, one of whom possessed
a
flight instructor certificate with
helicopter and instrument helicopter privileges.
Yanking
and banking can be lots of fun when performed at a safe
altitude in an aerobatic airplane. 
As improbable
as it sounds, we pilots occasionally allow our airplanes to
run out of gas. When we do, one would expect us to
execute a power-off landing to a reasonably safe emergency
landing site.
For
some reason, however, the pilot elected not to treat his
powerless airplane as a glider. Instead, he apparently
attempted to clear obstacles along the way pitching up
beyond his airplane's critical angle of attack, thus
producing a stall. This stall, when combined
with a yaw, likely produced a spin which, close to the
ground, was not recoverable. 
Imagine
the safety margin we could create for ourselves if we were
able to double the length of our runways! 
Free
sign up for
Over the Airwaves
It
was Forrest Gump of Hollywood fame that finally offered a
rational explanation for general aviation's chronic fatal
accident rate. He said,
"Stupid is what stupid does!"
The
Pilatus is a very capable airplane. It is
a pressurized, single engine,
propeller-driven, eight seat airplane. It has a
maximum takeoff gross weight of 10,450 pounds and is powered
by a Pratt & Whitney Canada PT6A-67B, turbo shaft engine,
which has a maximum takeoff rating of 1,200 horsepower.
We
often hear platitudes about old versus bold pilots, or
having personal minimums, or that it's better to be on the
ground wishing you were up there than the other way around. 
The
second way is to engage in systematic recurrent training
that stretches your operating envelope. Get some tail
wheel training, pursue that next rating, log some aerobatic
time, fly into Class B airspace in IFR conditions during the
Friday night "push."
