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At least two severely drunk airline pilots have been arrested before allegedly trying to fly passengers over the holiday period. The most recent incident was a Sunwing Airlines captain who was found passed out in the cockpit early Saturday while his flight was being boarded in Calgary, Alberta. The unidentified pilot had to be revived before he could be led off the aircraft and initial breath tests indicated a blood alcohol content of more than .24, three times the legal limit for driving a car in Alberta. Security staff, gate agents and flight crew colleagues all reported his “odd behavior” and called authorities. “We tested him approximately two hours after we took him into custody and he still blew at that extreme level," Calgary Police Sgt. Paul Stacey told Global News. “So I can’t tell you when he had his last drink but he was pretty high. So it probably wasn’t too long before we took him into custody is my guess.” The pilot, a Slovakian national working in Canada on a temporary permit, was to command the 737-800 first to Regina, Saskatchewan, to pick up more passengers before going on to Cancun. Sunwing found a replacement and the flight took off about two hours late. Police said they had to wait until the original pilot was sober enough to appear before a judge before they could charge him formally. The other incident took place on the other side of the world and the prelude was caught on video.

In that case, the pilot of a Citilink aircraft going from Surabaya, Indonesia, to Jakarta last Wednesday was hauled off the plane after passengers revolted when they heard him slurring his preflight announcements. Several of the 154 passengers got off the plane and demanded a replacement. He was also confronted in the cockpit but it's not clear whether that was before or after the passenger complaints. That was also caught on cellphone video. The pilot, identified at Capt. Tekad Purna, was caught on a surveillance camera as he weaved his way through security, dropping the contents of his briefcase and other items on the floor before lurching toward his aircraft. Purna and two senior airline officials subsequently resigned. “The pilot had committed serious violation of standard operation procedure that endangered passengers,” President Director Albert Burhan told Western Journalism. “We apologize for the discomfort. I have to be responsible for that and therefore I and my production director resign.” 

 

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Three people died when a Piper Arrow and a Luscombe collided near McKinney, Texas, Saturday. The aircraft were near Aero Country Airport when they came together. One crashed onto a road and another hit a storage yard and caught fire, burning some of the goods in the yard along with the airframe. The occupants haven’t been identified. There is no official word on the circumstances of the crash but witness Rodney Livermore had a clear view of the crash sequence.

"They were making a turn and one of the planes slid into the other," Livermore told local media. "You heard a loud crash and bang. One of them came straight down. The other one had a little control, but it was coming down. There was no stopping it.” Aero Country Airport is privately owned, public use facility with a 4352x60-foot asphalt/turf runway (17/35) and is operated by the property owners at the airport.

The Air Force marked the end of almost 60 years of service of the F-4 Phantom with a ceremony at Holloman Air Force Base in New Mexico just before Christmas. The last flying Phantom took off to assume its final role as a ground target for training pilots in more modern platforms. Holloman has been using remotely piloted and manned versions of the aircraft as targets for years and dozens have been blown out of the sky by the new generation of fighter pilots. The aerial targets, designated QF-4, are being replaced by old versions of the F-16. When the Dec. 21 ceremony was held, there were just 13 flyable Phantoms left.

McDonnell Douglas built more than 5,000 Phantoms in versions for the Air Force, Navy and Marines and it was sold to about a dozen other countries. Originally designed as a carrier-based interceptor, the big, rugged fighter was adapted to myriad roles, from dogfighting to bombing and electronic countermeasures. It could also carry nuclear weapons. Pilots praised its buckets of power and rugged construction as a lifesaver that compensated for it being less agile than some opponents.

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If Santa did a flypast of your hangar this year, you could go after him at Mach 1.3 in your own CF-5 Freedom Fighter. The little fighter, based on Northrop’s design, was built under license by Canadair in the 1960s and 1970s and this aircraft is being sold by a private owner in St. Augustine, Florida, for $1.8 million, about what the aircraft cost when they were built in Cartierville, Quebec. The owner of this one, a two-place trainer model, says it has low hours on it and has had many upgrades, including avionics and oxygen.

The Canadian version was modified from the original Northrop design with a unique innovation to decrease the ground roll on short runways. The aircraft has a two-position nosegear that can be lengthened to increase angle of attack. The result is a 20 percent reduction in runway requirement. The aircraft has license-built Orenda/GE J85-15 engines with afterburners. The inflight refueling probe was a practical necessity for the far-flung operational requirements in Canada since the aircraft only has a range of about 875 miles. The For Sale ad is on aircraftforsale.com.

Coast Guard crews resumed recovery efforts Sunday in Lake Erie for a corporate jet that disappeared off the shoreline of northeastern Ohio late Thursday. News reports say the Citation 525C, based in Columbus, Ohio, had flown earlier in the day to Burke Lakefront Airport in Cleveland with six on board. The aircraft departed the field about 11 p.m. for its return flight. Crews in Coast Guard boats and a helicopter along with a Royal Canadian Air Force C-130 took part in the search, made difficult with 12- to 15-foot waves on the lake. No signs of the aircraft or occupants were found and crews ceased their search at 7:30 p.m., and will turn over recovery efforts to local authorities, Cleveland.com reported. 

The jet's pilot and owner, the CEO of a local company, was flying his wife, two sons, and another parent and daughter, according to The Columbus Dispatch. The group had attended a Cleveland Cavaliers basketball game and was returning to Columbus. Flight data and reports from ATC indicate the 2012 Citation dropped off radar in a high-speed descent over the lake, moments after departing Cleveland. 

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Every year structural icing claims a small but steady number of airplanes. Many of the accidents are on approach in clear air—after the airplane has already collected a load of ice. We look at them afterward and wonder—the airplane had been doing fine—why did it crash well after it escaped from icing conditions?

Full-scale airframe ice flight testing and our ability to reconstruct icing-related accidents have gotten more sophisticated. Consequently, we’ve learned that tail stalls, rather than wing stalls, may be the culprit in crashes that occur during the descent or approach phase of flight. This matters because pilots have been taught how to recover from wing stalls (lower the nose, add power) but not from tail stalls, and the recovery from tail stalls is precisely the opposite (raise the nose, raise the flaps, reduce power). The consequence of using the wrong recovery technique can be fatal.

The infamous 2009 Colgan Air Dash 8 crash on approach in icing conditions to Buffalo, New York is believed, by some commentators, to have been caused by an experienced crew—having recently been through tail stall training—mistakenly believing they were experiencing a tail, rather than wing stall. The captain pulled back on the yoke and the first officer retracted the flaps.

Since recovery technique varies, you can’t recover if you don’t know which airfoil has stalled.

Radius Matters

If the opportunity presents itself, the next time you see an airplane that has landed with ice on the airframe, compare the buildup on the unprotected areas of the wing and tail. Also take a look at the antennas. You might be surprised by the significantly greater amount of ice on the tail and antennas than that on the wing.

Very simply: the smaller the radius of the leading edge, the faster and wider the ice buildup is. Therefore, the horizontal stabilizer collects a greater percentage of its radius in ice than does the wing. Even with but a half inch of ice on the wing there may be an inch or more of ice on the tail. 

To make matters worse, ice buildups tend also to take on interesting shapes—they frequently branch out from the leading edge, forming what appears in cross section to be horns. The net effect is that the smaller airfoil—the tail—gets relatively more ice than the wing, so the flow over it is more disturbed than the flow over the wing. The photo at the beginning of the article is from an icing lab. It shows a startling example of clear ice buildup on the small radius of the airfoil, along with dramatic ice horns that develop as ice builds.

The shape of ice buildups on the wings is a far bigger problem to an airplane than the weight of the ice. The wing and tail create lift partially because of a smooth airflow along the chord of the airfoil. When there is ice on the front, the airflow across the lifting surface (the top of the wing, the bottom of the tail) is no longer attached to the surface after crossing that ice buildup.

Aft of the ice there is airflow separation from the surface, creating what amounts to a void that has to be filled. The air coming over the ice rotates toward the airfoil and then flows forward, creating a rotor or vortex of disturbed air in the area of flow separation. See the illustration below.

Loss of Lift

This reverse flow means that portion of the tail’s airfoil is stalled—not providing lift. The size of this disturbed area or airflow separation matters. With more ice there’s more disturbed airflow. The higher the angle of attack, the greater the size of the area of disturbed airflow. If the area of disturbed airflow gets large enough, the entire airfoil stalls. Before that, if it moves aft far enough to cross the hinge line of the elevator, it has the effect of tending to pull the elevator toward it. See the next illustration.

This all becomes important because the tail of an airplane is usually lifting downward to overcome the nose-down pitching moment of the wing in normal flight. Remember ground school that the wing’s center of lift is usually behind the center of gravity. As the wing lifts upwards, the center of gravity pulls the front portion of the wing down—nose down force—which the horizontal tail overcomes by lifting downward.

In cruising flight icing is not as much of a concern for the tail as it is for the wing because the tail is at a low angle of attack, nowhere near its performance limits, so the burble or rotor behind the ice buildup stays close to the buildup and the vast majority of the tail has airflow that is attached and effective.

In cruise configuration, the problem with ice buildup is sheer magnitude on the airframe and the wings. That’s where you get so much drag and lose so much lift that you can’t hold altitude, the stall speed increases and you may either sink into the ground or stall the airplane and lose control.

Tail Stall Tale

A tailplane stall event typically begins with the airplane picking up some ice. As the pilot begins the approach, he or she selects approach flaps and notices that it’s difficult to trim the airplane and the elevator feels lighter than usual. The control wheel will move forward very easily but it’s difficult to pull it back. Often some mild pilot induced oscillation (PIO) begins that may be difficult to fully damp.

Struggling like this through the approach, once the runway is made, the pilot selects full flaps. Wham—suddenly, the airplane pitches down 45 degrees, the pilot tries to pull back on the yoke, but it’s immovable and the airplane crashes.

Either the tail stalled, or the flow separation under the tail moved so far aft that it reached the elevator and caused the elevator to deflect radically downward. The result is the same: the nose pitches down violently and recovery is the same in either case.

Flaps

Flap extension does two things to an ice-contaminated horizontal stabilizer, both bad. It changes the airflow aft of the wings, deflecting it downward, which causes increased downwash over the tail, increasing its angle of attack. This is depicted in the phtotograph below and it happens to both high- and low-wing airplanes.

With increased angle of attack and an ice buildup on the leading edge, the flow separation on the underside of the tail, the lifting part, is worse, and the area of disturbed air, gets bigger and moves aft.

Flap deflection also moves the center of lift of the wing aft, further from the center of gravity. This causes an increase in nose-down pitching force. To compensate, the tail must exert greater downward force, thus increasing its angle of attack still more and causing it to work nearer to its performance limit.

Increasing the horizontal stabilizer’s angle of attack increases the area of flow separation behind the ice buildup. When the area of flow separation reaches the hinge line for the elevator the relative low pressure of the flow separation or rotor acts to pull the elevator toward it, that is, downward.

Yoke Movement

With the normal, small changes in pitch of the airplane on approach, the size of the disturbed airflow area under the tail, behind the ice buildup, changes accordingly. The pilot feels a buffeting in the wheel—unlike pre-wing stall buffet that is felt, quite literally, through the seat of the pants.

The changing amount of “pull” on the elevator causes changing forces to feed back to the yoke. The pilot feels that the controls are light—easy to move forward (elevator down into the area of flow separation and lower pressure), but difficult to pull aft. It may be difficult to trim the airplane in pitch.

The pilot fights this and PIO begins. PIO adds to the rapidly changing angle of attack of the elevator, further changing the size of the area of airflow separation, and further increasing the rate of change to the downward-acting force on the elevator. Things are building on themselves, but the pilot may still be able to keep the airplane mostly under control.

When full flaps are added, the combination of increased downwash and the aft movement of the center of lift further increase the angle of attack of the elevator. The area of flow separation may get so big that either the horizontal tail simply stalls and quits lifting downward, allowing the nose-down pitching moment of the wing to act unopposed, or the elevator is physically pulled downward into the area of flow separation. In either case, the pitch down is sudden and violent. Pilots who have experienced it describe either getting light in their seats or actually being thrown against the seat belt.

Recovery

Recovery requires reducing the angle of attack of the horizontal stabilizer and getting the elevator away from the area of flow separation. That means raising the flaps, at least to the previous position. It also means physically pulling the elevator away from the area of flow separation by pulling back on the wheel.

There are reports that on some commuter turboprops the force necessary to pull the wheel back and get the nose up to the horizon may be as high as 400 pounds. The more realistic load for smaller aircraft is as high as the 100 to 125 pound range. That is still a huge amount of force. Be prepared for it.

Adding power makes a tail stall from ice worse. Power is always destabilizing to an airplane, although with no ice, the aerodynamic design of the airplane easily handles the power available. Adding power adds to the downwash effect, increasing the angle of attack of the tail. While the effect of a power increase on increasing the size of the area of airflow separation aft of the ice buildup is not as great as flap deployment, a power increase still increases the size of the area of flow separation. So, in the event of a tail stall, while you are retracting the flaps and pulling for all you are worth, reduce power as much as you can, counterintuitive though that may be.

Note also that increasing speed increases the area of flow separation under the horizontal stabilizer. It doesn’t seem to matter in cruise because the tail is at a very low angle of attack; however, once the flaps have been deployed, a speed increase will make matters worse. That is exactly opposite to the technique of dealing with wing icing and the need to stay well above the stall speed for the wing. With flap deflection in the equation, additional speed does not help. The solution? If you get into ice, leave the flaps up.

Diagnosis and Cure

How do you know if the icing problem you are wrestling is an impending wing or tail stall? There are some general rules. If the flaps are up and you are in cruise configuration, the pressing concern is wing stall. To the extent it gives any warning it will be in the form of airframe buffet. If you feel shaking through the seat of your pants, the problem is probably the wing—as redesigned by ice—approaching its critical angle of attack.

An impending tail stall gives a different set of warnings. If the pitch control gets “lighter,” particularly if it becomes easier to push forward on the yoke than it is to pull aft, be suspicious. It may become difficult—if not impossible—to trim the airplane and you may enter PIO. Further warning is given via buffeting in the control wheel itself, not in the airframe. If you have any amount of flap deployed and you experience shaking in the control wheel, it’s a good bet that it’s the tail that’s at risk of stalling.

The first defense against a tail stall from ice is to, obviously, avoid the ice. Unfortunately, that’s not always realistic. So, if you have ice on the airplane, leave the flaps up on the approach and all the way through landing. If the POH has a speed for approaching with ice contamination, use it. Otherwise, fly fast and do not close the throttle until the wheels are rolling on the ground (if you reduce power in the flare you may go from being above the power on stalling speed with ice to below the power off stalling speed with ice—a wing stall problem). Too many pilots have figured they had the landing nailed, pulled the power back in the flare and promptly hit so hard they damaged the airplane. If a power setting has worked all the way through the approach, don’t mess with success.

Also, if you picked up the ice at altitude and you’ve descended to a lower, ice-free temperature and the airplane is still reasonably controllable, consider staying there for a bit to see if you can reduce the ice through melting or sublimation.

If you miss the warning signs and do end up with a tail stall, retract flaps if deployed, reduce power and apply up elevator, possibly against extreme resistance.

After you taxi in and your pulse rate returns to double digits, remind yourself that ice is for drinks.

Rick Durden is an aviation attorney, is a CFII and ATP with type ratings in the Douglas DC-3 and Cessna Citation and is the author of The Thinking Pilot’s Flight Manual or, How to Survive Flying Little Airplanes and Have a Ball Doing it, Vols 1 & 2.

This article originally appeared in the December 2014 issue of IFR magazine.

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I’m sure I’m not the only one hearing this question: A friend or relative reports that a son or daughter is interested in a piloting career and, well, you’re a pilot, what’s your advice? I field this query carefully.

While I think the profession definitely has legs, my concern is that in the next two decades—if not sooner—automated and autonomous flight will have developed sufficiently to put downward pressure on both wages and the number and kind of flying jobs available. So if a kid asks the question now and he or she is 18, 20 years from now will be 2037 and our would-be careerist will be 38—not even mid-career. Who among us thinks aviation and especially for-hire flying will look like it does now?

I’ve been interested in this for awhile and I’m currently reading Rise of the Machines: A Cybernetic History by Thomas Rid. The author quotes an early cybernetic researcher, Norbert Wiener, as having written this of emerging automation in the late 1950s: “It is perfectly clear that this will produce an unemployment situation in comparison with which … the depression of the thirties will seem a pleasant joke.”

He overstated the case, right? So far, yes. But the truth is that majority of the jobs that evaporated from the industrial Midwest didn’t go to China, they were phased out in favor of automation. No one knows with a high degree of confidence what will happen in the next 20 years, or even 10. But companies in the aviation business have to plan for a future they can’t predict, so I asked various people in the industry when flight autonomy or automation will noticeably impact the workforce. Here’s what they told me:

You are asking a tough question. My quick answer is that we are at least 10 to 15 years away before there is true autonomous capability in manned critical aircraft. The key is how quickly the software can develop to effectively deal with crisis situations in a truly dynamic way. Although machines can now beat us in strategy games such as chess and Go, it is because they can run the simulations so fast they examine all alternatives. 

However, speed is relative as they still take time to reach the correct move. Such time is not available in a complex situation such as an aircraft moving at 500 knots. The best example I can give is Sully. The textbook said turn, Sully said glide and land straight ahead. 

It is definitely coming, but I still think it will not impact pilots for another decade plus. One side thing for me is does this impact GA (piston range) where people fly because they want to have some involvement in pointing the plane? Conversely, does it revive the industry by taking the low-annual-flight-time pilot risk out of the equation and allow more people to fly because it is one button from start to landing?

Rhett Ross
Continental Motors

I guess the answer would be this: When do you believe people will be transported autonomously? While the technical ability will be there in three to five years, it still would be another five for regulatory changes, so a total of 10 years.

Then many years to get people comfortable with the concept. So the long answer is 15 years at the earliest, but my real belief is never. Looking at population growth, air-carrier capacity, people’s acceptance of new modes of transportation, it all adds up to airlines that will need pilots now and into the future. It will not be a career in danger of shrinking. Add the pilot retirement problem and the next 15 years is boom time for new pilot careers.

Jack Pelton
EAA Chairman and former Cessna CEO

I think it will not impact pilot hiring and if I have to guess, I think, it will actually favorably impact pilot hiring. Autonomous flight capability is going to not just extend by a little, but by a lot utilization of aircraft, and GA in particular.

Technology is a way to reach out to masses and make something for a few available to more people. Our aviation system is still qualified by expertise. With autonomous flight capability, the pilot skills will be reduced to more monitoring rather than piloting, thus opening aviation to a much larger variety of candidates.

It is a huge opportunity for aviation. And commercial airlines, particular low-cost companies, have clearly understood that pilots are no longer the highest compensation in the salary scheme. Good or bad, we will leave an era for aviators to flyers with safer and simpler aircraft to fly.

Nic Chabbert
Daher

Behind the curtain, aircraft manufacturers are working on a single-pilot cockpit where the airplane can be controlled from the ground and only in case of malfunction does the pilot of the plane interfere.

Basically the flight will be autonomous and I expect this to happen in the next five to six years for freighters. For GA, autonomous flying capable aircraft are mainly a safety factor.

Christian Dries
Diamond Aircraft Austria

Not a clue, I'm afraid.

Richard Aboulafia
Teal Group

We have just been having this discussion inside Lycoming. As you know, we’re part of Textron Systems and the unmanned unit supplies UAV/RPV system soup-to-nuts, meaning from the aircraft operator to the ground station to the aircraft itself for multiple platforms (Aerosonde, Gray Eagle, Shadow, Orion).

You phrased the question using the words “autonomous flight capability.” I’d say “autonomous” is a pretty expansive and broad definition. That will be awhile. A better word may be “manned-unmanned teaming” or “augmented flight capability” that enables fewer (or lesser skilled) pilots to control the aircraft. Or one pilot to control multiple aircraft. The augmented situation is happening now (and has been happening) with flight engineers and navigators no longer in the cockpit and operators (not pilots) controlling UAVs with waypoint instructions. 

For the broader impact, the maturity of the military-use systems is at a point now where (my opinion) you are not talking about reliability problems with the technology. So technology readiness level is not the inhibitor. What will pace the impact will be the acceptance by people of people not being in the cockpit, whether by politicians, the FAA, the pilot unions or the passengers buying tickets. 

If there are people in the aircraft – whether military or civilian – they will want to see a warm body that they think is the pilot who did the walk-around to ensure the aircraft was safe to fly. But in 10 to 20 years, you may not see two people up front and you may not see multiple crews on long-haul flights. The skilled pilot will be engaged, whether from the cockpit or the ground remotely, when an unanticipated event occurs that the augmented flight toolkit was not programmed to handle.

So to answer your question, I think it’s happening now. But it’s not driverless-car autonomy. It’s humans augmented by machines to control complex equipment with simpler commands. Like Sulu controlling the Enterprise single handedly versus a hundred engineers launching Apollo.

Michael Kraft
Lycoming Engines

Maybe I am really old school, but I can’t see that happening in my lifetime. They are doing autonomous bus trials in Germany in 2022, I believe, which is not far away at all and seems harder to me than flying an airplane airport to airport.

But aviation is so conservative. I can certainly see autonomous flight becoming more mainstream, but to launch an airliner full of pax on a regular basis, I think we are very far away. That it would impact pilot hiring, I would expect at least two to three decades, if not more.

But then we all thought glass cockpits in new aircraft would be just an option.

Peter Maurer
Diamond Aircraft Canada

I think it is still many years off as people still feel that machines break. So until they have many years of problem-free operation, they will want a human in the cockpit. Even drones are still flown by a human at this point. Minimum 15 years. Probably 20-plus.

Jim Allmon
Blackhawk Modifications

The short answer is no time soon. The general public may be comfortable with a small quadcopter delivering packages, but they will be far less willing to accept large aircraft without a trained and qualified pilot at the controls.

George Perry,
Senior Vice President
AOPA’s Air Safety Institute

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AVweb readers send us hundreds of aviation photos each year. Here's a compilation of the best for 2016. Best wishes to all who view our channel for a happy and prosperous 2017.

You own it and pay for it, so you might as well take advantage of everything the FAA offers to any pilot willing to dig into the National Airspace smorgasbord and ace this quiz.

Click here to take the quiz.

As a 16-year-old student pilot I was on a short night flight from Hershey to Capital City airport (KCXY) in Harrisburg, PA.  I was told on initial contact to "report a three miles final for runway 26."

Me: "Piper xxx is three-mile final runway 26"

Tower:  "Negative Piper xxx...you're 4.5 miles out.  We've got the Big Eye on you!"

They were sure proud of their new radar.


 

Bart A. Frantz 

 

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