2015.0528 flying lessons - mastery flight trainingone explanation might be the hail threat....

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FLYING LESSONS for May 28, 2015 suggested by this week’s aircraft mishap reports FLYING LESSONS uses the past week’s mishap reports to consider what might have contributed to accidents, so you can make better decisions if you face similar circumstances. In almost all cases design characteristics of a specific make and model airplane have little direct bearing on the possible causes of aircraft accidents, so apply these FLYING LESSONS to any airplane you fly. Verify all technical information before applying it to your aircraft or operation, with manufacturers’ data and recommendations taking precedence. You are pilot in command, and are ultimately responsible for the decisions you make.

FLYING LESSONS is an independent product of MASTERY FLIGHT TRAINING, INC. www.mastery-flight-training.com

This week’s lessons: We all should know the extreme hazard of flying through thunderstorms. Nonpilots and novices think we’re afraid of being struck by lightning, which the least of a pilot’s worries in a thunderstorm. Hail is always a potential hazard (visualize someone shooting small cannonballs at your airplane at a couple hundred miles per hour). Airframe icing can be extreme. Even liquid precipitation can be so intense that it reduces the flow of combustion air into a turbine engine or through a piston plane’s air filter and, in some designs can significantly reduce the wing’s lift-generating capability.

In recent years we’ve learned about the hazard of misinterpreting weather data uplinks, especially NEXRAD radar images that can be as much as 20 minutes out of date by the time they are visible in the cockpit—when 20 minutes is a significant percentage of an air mass thunderstorm cell’s entire lifespan. The U.S. National Transportation Safety Board (NTSB) even issued a Safety Alert reminding pilots that cockpit NEXRAD weather uplinks from any source are not accurate enough to plot a course between or in the vicinity of thunderstorms…that a display of the “latency period” is the time since the NEXRAD image was transmitted, not the time that the individual radar images were recorded, which will always be older. See www.ntsb.gov/safety/safety-alerts/Documents/SA_017.pdf

There are times, however, when airplanes crash and it at least appears from the investigative process that the pilot was maneuvering in the vicinity of thunderstorms but did not actually penetrate a radar return that correlates to a storm cloud. What might cause that? One explanation might be the hail threat. Hailstones have been reported to have been encountered as far as 20 miles downwind of major cumulonimbus clouds. Generally storms of this magnitude have well-developed anvil tops; one of the “classic weather text” warnings about thunderstorms is to avoid “severe” thunderstorm clouds by at least 20 miles, and avoid flying beneath anvil clouds at any distance from the cloud boundary (a real challenge in the central U.S. where anvil clouds can extend scores of miles downwind of a severe storm cell).

“Regard as severe any thunderstorm,” the U.S. FAA tells us in Aviation Weather, chapter 11, “with tops 35,000 feet or higher whether the top is visually sighted or determined by radar.” In my experience that’s the vast majority of all thunderstorm cells. From a hazard-to-flight standpoint, we should avoid almost all storm clouds by at least 20 miles. See www.faa.gov/documentLibrary/media/Advisory_Circular/AC 00-6A Chap 10-12.pdf


That means, by the way, that storm clouds must be at least 40 miles from one another, with no overhanging anvil, for you to split the difference and fly between them. That’s a big gap in a line of storms. The classic texts actually advise us to avoid trying to fly in areas with more than 6/10th coverage of thunderstorm cells…even with active airborne weather radar.

But what about crashes that follow an attempted deviation around storms on the upwind, presumably non-hail-ejecting side of a cumulonimbus? How might we explain an airplane that seems to be flying along just fine, then fails to respond to Air Traffic Control transmissions and suddenly plunges downward into the ground?

The late centenarian pilot Captain Johnny Miller wrote prolifically about his storied career as an aviator “from Jennys to jets,” as he put it. John once wrote about an experience he had while crewing an Eastern Air Lines DC-8 in an area of strong thunderstorms. He noted that the airplane unexpectedly hit severe turbulence so intense that, even strapped in with two shoulder harnesses, he was flung upward and sideways, and hit his head on the upper sidewall hard enough that he was momentarily dazed. John speculated in the article that in a light airplane it would not be unthinkable that around thunderstorms a lone pilot with no crew backup might hit the headliner with enough force to knock him/her unconscious and unable to control the airplane…or as he mused, perhaps even break the pilot's neck. This, John suggests, might explain airplanes that lose control and crash for no apparent reason when they have strayed too close to a thunderstorm but may not have actually penetrated the storm cloud. See http://frobbi.org/dcpa/JohnMiller.html

This NTSB preliminary report, published this week, reminded me of John Miller’s decades-old LESSON. A pilot knocked unconscious by turbulence would explain this and several other similar events I recall from my nearly 25 years of actively tracking aircraft accident trends. See www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20150519X32600&key=1

It’s stylish to selectively choose from the LESSONS of history, picking the “old school” ways that support our goal or point of view and deriding as outdated any past wisdom that does not let us do what we want to do. This “selective wisdom” is in no means limited to aviation, but it runs rampant among us as well.

One of the great wisdoms of the past is to consider all thunderstorms to be dangerous, avoid flying closer than 20 miles from a thunderstorm cloud, and not to fly under an anvil cloud blowing off the top of a storm.

The good news is that modern NEXRAD weather uplinks, inaccurate though they are for picking a way through and around storms, provide a great way to avoid areas of general thunderstorm development… but only if we are willing to use them for their intended purpose, as a way to detect storms from further away so we can alter course to avoid them before getting within 20 miles of a cell where extreme turbulence can toss us out of control. Questions? Comments? Let us know, at [email protected]

See http://www.pilotworkshop.com/tip/clearances/qa-tip


Debrief: Readers write about recent FLYING LESSONS:

Reader David Heberling writes about pilot professionalism as discussed in the past couple of weeks in FLYING LESSONS:

I want to thank John Rosenberg for his post. I agree and support everything he said.

There was lots of response to last week’s LESSONS on the limitations of see-and-avoid when visual flight rules (VFR) airplanes are operating legally, but just within the minimum clearances, above, below or laterally from clouds. Airline Transport Pilot (ATP) and lightplane Designated Pilot Examiner (DPE) Dale Bleakney writes:

Thanks as always for your wonderful newsletter. I like your article about cloud clearance when in VFR conditions. It is something that I always take seriously. I also encourage students or pilot applicants to do the same.

First, I have a friend from my past who was injured as part of a collision with another airplane. When I met him in the early ‘70s he was flying and instructing with part of one of his legs missing. He lost part of his leg when it was damaged as part of an ejection from an F-100 [USAF fighter] that he was flying. The F-100 was flying IFR and descending through a cloud deck when he impacted a Cessna 172 that was climbing through the deck to get on top. The student and instructor in the 172 were killed. My friend was able to eject. He was injured enough in the ejection [that] they had to amputate part of his leg. Word to the wise: the “big sky theory” is not always enough.

Second, I was flying on an IFR flight plan and was cleared for an ILS approach at [a nontowered] airport. The weather was about 600/2. The airport was a class G airport to 1200 AGL. A student and instructor were in the pattern, below the overcast. I broke out on the ILS and much to my surprise, there was a 172 very close in front of me. I was doing about 120 knots and the 172 was much slower. I was able to avoid the 172 but it got my attention. The pilot in the 172 was not talking much on the radio (I did not hear him) and approach was not aware that they were in front of me. I suspect the transponder was turned off or not installed, as it was not required at the airport. They were not on an IFR clearance. I guess they were using “it’s a big sky, and only a little 172” theory. We see how that was proven wrong.

This is a perfect example of the dilemma, and similar the experience I related last week in which I broken out on the approach to find a pipeline patrol airplane between me and the airport. In Class G airspace the VFR requirement is “one mile visibility and clear of clouds.” Traffic in the pattern, as Dale described, would generally be 800 to 1000 feet AGL, below the 1200 AGL base of the controlled airspace and indeed in Class G. As long as the Cessna in the pattern was not physically in the clouds it was perfectly legal…although I’d like to think the instructor would have at least considered the possibility of an IFR airplane popping out of the clouds in such low conditions. Dale continues:

Both of us were legal, but both of us were almost killed. One mile clear of clouds in class G is pretty scary to me when in the vicinity of an airport. I always try to monitor the CTAF radio frequency and make blind transmissions but that still doesn’t protect against the airplane that is without radios, not monitoring, or on the wrong frequency.

For the [IFR] operators that think that keeping the IFR clearance to the ground in VFR conditions protects them, that only works if someone is not SVFR [Special VFR], the airport is class E to the surface (and less than 1000/3), and no one is in the pattern without radios. In my opinion, looking outside and following published traffic patterns is always a better idea. Asking for anyone in the area to advise is against the current AIM guidance and still doesn’t guarantee that people will respond. People could be there as stated above.

Thanks, Dale. Frequent Debriefer David Heberling is back, adding:

I cannot see an airplane at all outside of 10NM unless it has a contrail behind it. That is a large airplane. Small airplanes are even [harder] to pick out. I really depend on TCAS [Traffic Collision Avoidance System, a requirement in transport-category jets] to help me find traffic. Without it, it is almost hopeless. I have searched in vain for traffic called out by ATC only to be told cleared of traffic a short time later. Neither of us saw the traffic. This happens more often than is comfortable. I do not know anyone whose eyesight is calibrated to determine whether he is 1000 or 2000 feet or 1 mile away from clouds. Scud running is not good for anyone's health.

More and more the airplanes I fly and in which I instruct are equipped with some sort of traffic


detection device, whether it’s a TCAD (Traffic/Collision Alerting Device, which points out nearby aircraft including their relative altitude, but unlike TCAS does not provide any recommended avoidance maneuver), TIS (Traffic Information System, once “the next big thing” but since relegated to the “might have beens” that detects certain aircraft in Approach Control radar airspace), or early adopters of ADS-B. Like others, I’m somewhat amazed at the number of airplanes I may not have seen without the technology. With all these devices, however, I’ve found that technological detection makes it a lot easier for me to visually acquire the traffic and then avoid it visually. That’s the proper use of all these technologies: they tell you where to look, eyes outside of the airplane, for other airplanes.

David has another excellent point that I did not specifically address last week: the extremely subjective nature of trying to determine you are 1000, and not 900, feet away from the edge of a cloud, or that you are indeed cruising 500 feet below the bases and not 400 or 200 feet beneath the clouds. Thank you, David.

Flight Instructor Bob Dilk notes:

If you are on an IFR flight plan and ATC calls out VFR traffic, if you do not confirm that you can visually see the traffic, ATC will keep you separated ( I think it is 3 miles minimum) This is even in CAVU [clear air/visibility unlimited] conditions.

That's indeed correct, if the VFR traffic is participating in ATC services and its altitude is verified to ATC. In that case you (the IFR airplane) may be given a vector for traffic avoidance—since participating VFR traffic is not "controlled" (except in class B airspace) it's the IFR airplane that will be moved to avoid the conflict.

That's why I suggest that VFR airplanes participate in VFR Flight Following if they are operating anywhere near the limits of cloud clearance and/or visibility. Nonparticipating airplanes might be called out as “traffic, altitude not reported” or “not verified,” but ATC will not necessarily protect IFR traffic from non-participating VFR airplanes.

Reader Kent Stones chimes in:

I just read your blog on mixing IFR and VFR traffic with clouds. I am now a much more confident IFR pilot since installing ADS-B In/Out. I can supplement ATC traffic separation with my own display. This feature alone makes the ADS-B investment a good value.

ADS-B is indeed a great technology, Kent. But it's only foolproof if everyone has ADS-B In technology. That’s not part of the coming (2020) mandate. We’ll still need to see and avoid.

Instructor Alan Davis writes:

An excellent LESSON for see and be seen. I can speak from experience that I have seen many VFR pilots that unfortunately do not follow the rules. Perhaps it is because we don't stress enough that when you are less that the minimum distances from the clouds, you are not, in fact, any longer VFR! If you are that close, you can be in them before you know it, and inside of the minimum separation, you have “gone IFR".

Perhaps the more salient point is made near the end of your piece: that the rules have not changed since the dawn of aviation. We probably need to revisit those rules and make them more relevant to today's environment [even] at the risk of pilots thinking that their rights are being infringed.

Thank you, Alan. David Roger cites an old study I’ve not yet found online, but which sums up the issue:

There is a very early MIT Lincoln Labs report on the probability of [the pilot of] one aircraft seeing another [aircraft]. The study used a typical general aviation aircraft talking to ATC while another general aviation aircraft passed 500 to a 1000 ft above or below the first aircraft on a converging course from between [nine and three o’ clock] relative to the aircraft under ATC control. The converging aircraft position was called out to the aircraft under ATC control. The probability of the aircraft under ATC control seeing the converging aircraft inside of one mile was less than 50%.

I have confirmed this result in every day IFR flying while in VMC.

The LESSON for VFR pilots is that you should remain far enough away from clouds to be assured you could see and avoid a 200-knot (or faster) IFR airplane that zooms out of the clouds


without warning beside, below or above you. That probably means a distance much greater than the minimums allowed under visual flight rules. Remember this applies to airplanes dropping out of the clouds near airports when you are legally flying “clear of clouds.”

The LESSON for IFR pilots is to be ready to scan for conflicting traffic as soon as you emerge from the clouds, and to make radio calls on the advisory frequency when approaching a nontowered airport. You cannot expect ATC to protect you from VFR traffic that is not also participating in ATC services, and by definition ATC will not keep you separated from airplanes in Class G airspace such as close to the ground near a nontowered airport. Comments? Let us learn from you, at [email protected]

After 46 years and 8000+ hours of flying, I always learn something from your LESSONS presented here. I can never be too safe or too knowledgeable when it comes to flying. Thanks for all you do trying to keep us all safe. – Ron Hyde

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See and Avoid Almost as if participating in the Debrief from the past two weeks of FLYING LESSONS, NTSB this week issued a Safety Alert “urging pilots to vigilantly look out for other aircraft and to make their own presence known…. As a pilot, your first job is to fly your own airplane,” said NTSB Chairman Christopher A. Hart, who is also a pilot. “Part of that job is to scan for other airplanes. On-board traffic advisory systems are not a substitute for an outside visual scan.” Read NTSB Safety Alert SA 045. See www.ntsb.gov/safety/safety-alerts/Documents/SA_045.pdf

For Australian Readers CASA has announces another series of seminars for pilots and engineers. The live events will each cover one or more of these topics:

• Questions and Answers regarding Licensing regulations • Ageing Aircraft Management Program • Airservices Australia safety issues – communicating with ATC and the Navaid Rationalisation

program • ATSB issues – How to access Safetywatch and other safety related material from the ATSB

website • BOM issues – Graphical Area forecast and TAF review • Interacting with CASA via the upgraded Self Service Portal and the new Medical Records System

(MRS) • CASA Educational Resources

For a list of all seminars, dates and location see www.casa.gov.au/avsafety.

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Personal Aviation: Freedom. Choices. Responsibility. Thomas P. Turner, M.S. Aviation Safety, MCFI 2015 Inductee, Flight Instructor Hall of Fame 2010 National FAA Safety Team Representative of the Year 2008 FAA Central Region CFI of the Year

FLYING LESSONS is ©2015 Mastery Flight Training, Inc. For more information see www.mastery-flight-training.com, or contact [email protected].