September 2015

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Asymmetric Loads And Maneuvering Stalls

Subscribers Only - Almost any time the discussion is about stalling at greater than 1g, it usually involves symmetrical flight, where all portions of the airplane’s structure are experiencing the same g-loading. But what if, say, one wing is at 2g and the other is at 3g, as might be the case in a rolling (banking) pull-up from a dive? The rising wing is experiencing greater g loading because it’s generating more lift. The descending wing, on the other hand, experiences less loading because it’s not generating as much.

How It Goes Off The Rails

According to Dismukes and his researchers in a presentation, “The Hidden Complexity of Cockpit Operations,” conventional wisdom tells us “pilots become accustomed to concurrent task demands, interruptions, distractions and disruptions” while the truth is “pilots routinely manage multiple, competing, concurrent task demands just fine.” At least until there’s an interruption. The presentation lists four situations when pilots are vulnerable to omissions when performing routine tasks:

Of Rams And Frats

Subscribers Only - One approach to assessing risk, covered in the FAA’s Risk Management Handbook, is to use a risk assessment matrix (RAM) like the one depicted at right. The matrix simplifies part of the risk assessment process, since once likelihood and severity are determined for a given risk it’s easier to determine when mitigation is required.

In Need Of Some Restraint

Subscribers Only - One of the side benefits of having some spare airframes, a test facility and a bunch of motivated engineers is the other kinds of testing you can do. According to Chad Stimson, NASA’s project manager for the ongoing ELT testing, other data also is being collected, mostly as a supplement to earlier studies.

Think Tactically, Plan Strategically

Pilots routinely make strategic plans for their flights. By expanding that idea a little to imagine some “what ifs” at various points along the planned flight—weather deterioration, passenger problem, airplane or system malfunction, or other potential hazard—and then decide on alternative plans for each major stage of the flight, the risk of plan-continuation bias and the negative effects of snowballing workload and stress are reduced.

Smoke vs. Clouds

Subscribers Only - Smoke is colloidal suspension of particles dispersed in a gas, a.k.a an aerosol. Heat from the fires creates violent updrafts carrying the particulate remnants of former trees, grass and sage brush to significant heights. When big fires are nearby, it’s not uncommon to have bits of ash falling from the sky. Like any rising column of air, with some moisture present, cooling may condense water vapor to form a cloud as well. I would not willingly fly IMC into a smoke cloud from an active nearby fire. As smoke cools and disperses and mixes with atmospheric air masses its wilder nature blends in with regular air.

Requiring Risk Management

Subscribers Only - In the new private pilot ACS, Area of Operation 1, Preflight Preparation, Task D, Cross-country Flight Planning (see excerpt at right) lists skill item 3, “Recalculate fuel reserves based on a scenario provided by the evaluator.” This requirement is largely unchanged from the PTS system. However, under the ACS the applicant must also be prepared to demonstrate knowledge about route planning and the procedure for calculating fuel reserves.

Cockpit Multitasking?

The term “multitasking” originated in the computer industry and refers to a machine’s ability for perform more than one task simultaneously. Even though modern operating systems with which we’re all aware provide the illusion of multitasking, true implementation on a computer requires a multiple-core processor. The same could be said for humans.

Teaching PAVE

Subscribers Only - Flight instructors exist, at a minimum, to impart knowledge gained from experience, preferably their own. In the past, that’s how risk management was taught: by telling “there I was” stories. Since younger, less-experienced instructors don’t have the same backgrounds as their senior colleagues, risk management concepts and tools were introduced. Yet some instructors may not fully understand or implement them. Here’s a primer on what students need to know.

Laws Or Sausages

If you’ve been paying attention to the GA industry’s efforts to deregulate the FAA medical certificate, you may know they’re proceeding along multiple paths. Progress is being made, but it’s slow and often not easily identified. Such is the nature of political thrust and drag. As you may recall, eliminating the need for an FAA medical certificate has been proposed for non-commercial operations of airplanes weighing 6000 pounds or less. It’s based in part on the success of the sport pilot certificate and the 10-plus years of experience we’ve had with pilots using a state-issued driver’s license to demonstrate their medical fitness.

Negative G?

Dr. Banner’s article in July’s issue, “In-Flight Fires,” mentions to bank 45 degrees during an emergency descent to create positive g loading and help offset negative g forces. Question: Generally speaking, why can airplanes withstand (or be certified for) greater positive g load limits than negative? Stated another way: Why are negative g loads more restrictive? Thanks for a great publication!

New Certification Standards

Subscribers Only - The FAA and industry have spent the last three years preparing to replace the existing practical test standards (PTS). As a result, the new airman certification standards (ACS) will go into effect in 2016 for all airman certificates and ratings. This new system can potentially improve the general aviation safety record, but only if flight instructors, designated pilot examiners and FAA inspectors are prepared to teach, test and administer the new system.

Why Smart Pilots Crash

I’ve noticed there is a bias, sometimes spoken aloud, that a pilot who made some sort of a mistake and had an accident was either not terribly bright, lacked basic skills or just plain didn’t have the magical “right stuff.” As an instrument instructor, I’ve certainly seen pilots with poor skills or who weren’t terribly bright or had lousy judgment, and some of them crashed an airplane. I’ve also seen some extraordinarily good pilots who were possessed of all the right stuff imaginable, who also made mistakes and crashed.

Maneuvering Stalls

Subscribers Only - One of the first things primary students learn in their training is the relationship of airspeed to stalls. Unfortunately, the Primacy Law can take over, leaving some pilots with the unshakable belief stalls only can happen at stalling speed, either clean (VS/VS1) or in the landing configuration (VS0). That’s basically true in 1g flight but not if any additional loading is placed on the wings, as often is the case when we’re maneuvering. In that situation, stall speed increases, sometimes dramatically.

Smoke Gets In Your Sky

Subscribers Only - The blue of a dry western sky can be breathtaking. But just after winter’s overcast gives way to clear and deep blue, an insidious menace begins to turn the blue skies white: smoke from the summer fire season. If the national news is covering numerous large western fires, anybody planning a flight in the western U.S. between July and October needs to be prepared to factor smoke into their pre-flight briefings. Check the fire map, or at least glance at the distribution of forest-fire TFRs.

NASA’s Latest Crash Tests

Subscribers Only - If there is any one thing guaranteed to frustrate an airplane owner—there actually are several, but work with us here—it’s the emergency locator transmitter, or ELT. The ELT, which was mandated by Congress in the early 1970s, got off to a bad start. Relatively short deadlines meant there weren’t enough of the devices available to meet the mandated demand. And they failed to activate in a crash more than 75 percent of the time. When they did activate, a whopping 97 percent were false alarms, according to the Aircraft Owners and Pilots Association (AOPA), resulting from something like a hard landing.

Fatals Higher In 2014

Subscribers Only - The NTSB in early August released preliminary general aviation accident statistics for 2014. Sadly, and despite major efforts at the FAA and within industry to enhance safety, the NTSB’s preliminary 2014 data show an increase in fatal general aviation accidents, from 222 in 2013 to 253 in 2014. Our calculator says that’s a 13.9 percent increase in fatal accidents between 2013 and 2014.

Acro Tyro

Subscribers Only - Just as there are different airplanes optimized for different purposes, pilots fly for different reasons. For some, it’s just a job, akin to driving a bus. For others, it’s a means of personal and business transportation. Still more fly for recreation, like sightseeing or aerobatics. Droning along in the stormy clag and hand-flying an ILS to minimums is the epitome of flying skill for some pilots. Others perhaps couldn’t fly an ILS if they had to but can fly, say, a loop or an Immelman to perfection, or safely get in and out of a back-country runway. Different strokes for different folks. Fortunate pilots may combine all of these activities, and others, into their flying career.

NTSB Reports: September 2015

Subscribers Only - At about 1705 Eastern time, the airplane touched down short of the intended runway. The commercial pilot sustained a minor injury; the pilot-rated passenger was not injured. The airplane was substantially damaged. Visual conditions prevailed. Abeam the runway threshold on downwind, the pilot lowered wing flaps to the first notch and moved the mixture control to full rich but did not turn on carburetor heat. While on final at 500 feet agl and 80 mph, the next thing he knew they were on the ground. He indicated the airplane descended due to a microburst, but there was no rain shower nearby. He also stated the passenger attempted to add full power, but was too late. He stated he did not stall the airplane.

Family Affair

The rule passed down from a father active in aviation to boys of teen age learning to fly an 85-hp Cessna 140: “Never tie down or hangar the plane after a flight without topping off the tanks.” It was good advice for the two of us flying the same plane: courtesy, good habits and prevention of water condensation in hot, humid Kansas.

Strutting

During landing gear retraction tests, it was noted the nose wheel assembly would contact the right nose gear door’s aft hinge during landing gear cycle. Also, the nose wheel assembly contacted the nose wheel well structure when fully retracted. Precision measurements determined the nose strut assembly-to-aircraft-structure attach points were misaligned.