Aviation Safety

The latest-technology glass panels do many more things than the old, tried-and-true “steam gauges” with which many of us grew up. Through the “magic” of a software-driven display supported by various sensors, modern flight instrumentation can provide easy-to-read attitude information and a wealth of other data that simply wasn’t available before. But there’s no free lunch. Along with their additional capabilities and accuracy, glass panels also bring different failure modes to the cockpit. One of these new-tech failure modes involves the way in which they determine the aircraft’s heading, along with other information, most of which firmly belongs in the nice-to-have-but-not-critical category. In many situations, losing heading information isn’t the end of the world—especially if GPS navigation remains available—but it can have a ripple effect on the panel’s various other systems and capabilities. I recently learned the hard way how failure of the heading sensor(s), usually a magnetometer, may not be a failure at all, depending on how the equipment is designed and installed.

By the time student pilots near the practical exam, they’ve usually got a pretty good idea of how and why to calculate density altitude (DA). If they’re lucky, they’ve even done some high-altitude takeoffs with an instructor, or at least simulated DA’s effects by using much-less-than-full power settings on a few takeoffs. Those tables and graphs overlook an important characteristic of the air in which we’re trying to fly: its humidity. Two classic concerns with mountain flying are density altitude and pressure altitude. Actual altitude doesn’t affect aerodynamic performance. Most of us plan our high-elevation arrivals and departures as early in the day as practical, and are extra attentive on warmer days when seated behind a normally aspirated engine. While reduced horsepower is certainly one reason to be wary of high-DA situations, the thinner air also means higher true airspeeds—and lower indicated ones—resulting in the airplane “thinking” it’s higher than it really is. The impact is felt through mushier controls, since there are fewer air molecules flowing over them. There’s also an impact on propeller efficiency, since its blades are airfoils. The net effect, of course, translates into longer, faster takeoff rolls.

Seemingly for generations pilots have argued over which controls speed and which controls altitude: power or pitch. At varying times the FAA contributed support to both sides with publications outlining flying techniques and training information. The very existence of the arguably adolescent-level debates ignores the hard reality: In powered aircraft neither one works alone. To achieve optimum performance in any setting requires balancing the two to best match the needs of the moment. Different combinations—and different sequences—give us everything from the best climb to the best cruise to the best economy to an optimal descent profile or best-profile for an instrument approach. In all cases, the power equation varies according to the altitude you seek, and the pitch attitude necessary varies with the desired airspeed. Just as an aircraft needs to obtain and maintain a specific pitch angle to match its bank angle in a level turn at any given speed, smooth, coordinated flight requires managing both pitch and power. But before we discuss how best to achieve the desired balance, let’s return to the basics of the impact of pitch and power on a powered aircraft.

As a student of NTSB reports and an active instrument flight instructor, I have come to the conclusion we do not stress preparedness for the missed approach procedure enough, either in initial instrument training or in instrument proficiency checks. In addition to collisions with obstacles because of an improperly flown missed, the General Aviation Joint Steering Committee, an FAA/industry working group charged with identifying and mitigating the causes of fatal general aviation accidents, has identified loss of control during a missed approach as one of its focus scenarios. This suggests that—even when the pilot attempts to fly the missed approach procedure properly—the workload of doing so may be greater than the pilot is prepared to handle. So how can we make certain we are properly briefed for the missed approach, so we know how to fly it correctly? What can we do to reduce pilot workload while flying the missed?

According to the NTSB, “Experimental amateur-built (E-AB) aircraft represent nearly 10 percent of the U.S. general aviation fleet, but these aircraft accounted for approximately 15 percent of the total—and 21 percent of the fatal—U.S. general aviation accidents in 2011.” With those numbers in mind, along with the fact E-ABs represent one of the fastest-growing portions of general aviation in the U.S., the NTSB last year initiated a major study of the segment.The study’s results were adopted by the NTSB in May 2012, after detailed analysis of accident records going back 10 years, in-depth investigations of all E-AB accidents during 2011, a broad survey of E-AB aircraft builders and wide-ranging discussions with industry. What, if anything, did they find? What were the study’s recommendations? Most important, can the study’s results be applied to those of us not flying so-called “homebuilt” aircraft?

Not all that long ago, flying in thunderstorm weather was more of an art than a science. Weather radar hadn’t been invented; the only real technology available was to use the ADF and avoid areas to which its needle pointed. Grizzled veterans with years of experience flogging DC-3s across the Great Plains had developed their personal methods for dealing with them. Too often, those methods allowed penetration—sometimes at low levels, maybe at higher ones—and didn’t stress avoidance. These days, a pilot with a fraction of the experience those captains had is favored with many more tools with which to locate and avoid convective weather. In heavy-iron operations—and even smaller ones—extremely capable airborne weather radar is the norm. Even flivver drivers can access satellite- or ground-based Nexrad weather radar imagery for not much in the way of expensive hardware or subscriptions. The Nexrad option also affords pilots the ability to scroll well beyond an airborne radar’s range to look at conditions they won’t encounter for hours, if ever, in near-real-time.

I looked up from my checklist to see a 20-foot wall of flame and smoke coming at me very rapidly. The only good thing was I would be taking off into the wind. Five years earlier, this old dirt and grass road near the settlement of Rogersburg, Wash., was used as an airstrip. When ownership changed from private to the BLM, the airstrip closed. It took five years of negotiating with the feds, including Congressional, AOPA and EAA involvement, to get back part-time use. This dirt and grass strip is 1550 feet long at 850 feet msl and parallels the Snake River. Shortly after BLM again allowed access, we got permission to mow it. Two friends used their Super Cub to fly in a brand-new lawn mower and I brought a weed-whacker. I parked my 172 at the end of the strip, in front of the Super Cub.

It’s been a rough few years for private aviation. The advent of GPS, moving map displays and so-called plastic airplanes in the 1990s brought with them renewed growth and interest. Much of that persisted, despite best efforts from national agencies concerned with security above all else, during the following decade. By 2007, signs of economic upheaval put a damper on flying activity. By the time 2008 and its sky-high aviation fuel prices rolled through, used personal aircraft were being sold at unheard-of low prices. Both trends flattened out in the years since, but fuel remains a significant operational expense and many used airframes aren’t worth what they were 15 years ago.

While complying with Service Bulletin 55-3835 “Installation of Empennage Inspection Access Panels,” the horizontal stabilizer forward spar and ribs were found not riveted correctly from the factory. Many rivets that go through the forward spar are too short, and where the rib and forward spar come together, the rivet misses the rib. We have found this same problem on other aircraft we have inspected.

I cannot tell you how disturbing the attitude of the sidebar “Paper? Or Plastic?” accompanying September 2012’s article, “Seven IFR Prep Tips,” was to me. I have been flying for over 40 years, most of them professionally. Having earned my instrument rating in 1976, a paper chart was the only choice and it has served me well all of these years. It does not need toxic batteries and it always works. Yes, the new gadgets are shiny and slick and do all sorts of wonderful things. However, aviation is an expensive activity, and those electronic devices are not cheap. Subscription costs have a habit of accumulating and escalating. I have recently changed to the atlas style of paper low-level en route charts. That means no charts spread across the cockpit. You are correct in saying that IFR flying takes planning. This is true of any cross-country flying. Weather is the biggest variable in flight planning and takes up most of the planning stage and all of the actual flying. No, I do not have in-cockpit weather other than what I can see out the window. Under those conditions, all weather avoidance is strategic, with no tactical avoidance available.