Tuesday, August 19, 2008

Precision Obstacle Free Zone



At my home airport a Precision Obstacle Free Zone (POFZ) was recently created at the arrival end of runway 27 right. The deadline for POFZ markings to be applied to all U.S airports was January 1, 2007. My understanding was that airports that didn't meet this deadline had to raise the ILS approach minima for any affected runways.

The POFZ area is demarcated using the same surface markings used for an ILS critical area: An area that is kept free of vehicles and aircraft to prevent interference with the broadcast signals from the localizer and glideslope. The motivation for the POFZ is actually to keep obstructions from penetrating the TERPS 34:1 obstruction plane that leads to the runway threshold. Depending on the runway and taxiway layout, the holding area may be much further from the entrance to the runway than a conventional ILS critical area though the surface markings are the same.



It's fascinating to see how many pilots react to the ILS critical area surface marking. Many pilots and instructors avoid taxiing over those markings, even in VFR conditions. These pilots don't seem to understand that the ground controller is required tell you when you shouldn't enter the area.

A POFZ is only protected when an aircraft is flying the ILS approach, is within 2 miles of the runway threshold, and the ceiling is being reported below 250 feet and/or the visibility is less that 3/4 statute miles or the RVR is less that 4000 feet.

An ILS critical area is protected when an aircraft is at or inside the Final Approach Fix, the ceiling is being reported as less than 800 feet and/or the visibility is less than 2 statute miles.

A POFZ is considered clear even if the wing of an aircraft holding on the taxiway penetrates the POFZ, but the tail or fuselage must not penetrate the POFZ.

If the POFZ is not clear, the minimum height above touchdown is 250 feet and the minimum visibility is 3/4 statute miles.

At my airport, crossing into the PFOZ is necessary for light aircraft to get into the best position to do their engine run-up before takeoff. Since there is no officially designated run-up area for runway 27R, turning around to do your pre-takeoff checks before the ILS critical area surface markings actually puts you in an area where the jet blast from a large aircraft taxiing on a perpendicular taxiway could really rock your world.

Jet bast encounters are not at all obvious to most pilots until they experience being in the wrong place at the wrong time. Once that has happened, it becomes easier to think ahead. And remember that if the conditions are VFR, you should be able to cross into an ILS critical area. If you have any doubts about entering an ILS critical area (or POFZ), you can always ask the ground controller for guidance.

Sunday, August 17, 2008

Ramp Rage

One part of becoming a pilot is learning to deal with your emotional reactions to flight. Here's an example: When flying the traffic pattern and turning from the base leg to final, a lot of the earth appears in the windshield. For most new pilots, that primitive, survival-oriented part of the brain often kicks in and tells them to pull up to avoid certain death, even though pulling up is usually counterproductive. The view out the window in this situation is actually a bit of a visual illusion: The aircraft is pitched down slightly, in a descent. Combine that with the bank angle required for the turn and to the inexperienced observer, it appears as if the aircraft is pitched down more that it actually is.

Another example is when a student pilot is first learning to land. It's not uncommon to feel panic, fear, anxiety, and/or a loss of control. With practice, you come to realize that things are usually not as out-of-control as they appear. As you learn how to handle the aircraft, the adrenaline lessens and the emotions fade, allowing you to focus on the task at hand. This adaptation process can lead some pilots to think that feeling fear is bad and should be suppressed, denied, or hidden. Yet fear is not always a bad thing when it is kept in context. Acknowledging fear might just keep you alive and out of harm's way.

Certificated (or licensed) pilots who have flown for any significant amount of time have had the unpleasant experience of getting closer to another aircraft than they would have liked. I've had this occur on the ground and in the air more times than I would have liked, but the result is always the same: A sinking feeling in the pit of my stomach, followed by a sense of relief and an almost immediate moderation of the emotions that surface as the adrenaline is subsiding. If you don't put the emotional component in context after a close encounter, you'll never get back into an airplane.

This past week I witnessed a Cherokee pilot who decided to taxi between our aircraft (parked at a fuel island) and a twin-engine aircraft that had started its engines, but had not begun to taxi. When I saw this gentleman start moving and I realized that he was going to try to "thread the needle" between our Skyhawk and the Twin Comanche, I knew it was going to be very tight. So I walked over to give him signals should he get too close.

Pilots who are in a hurry while taxiing often seem a little angry or irritated and this Cherokee pilot was no exception. He seemed pissed-off and hellbent on his course of action as taxied past our aircraft with his wing beneath our wing and with just inches to spare between his other wingtip and the Twin Comanche's wingtip fuel tank. It was a stupid, dangerous, and selfish display. Ironically, the twin began to taxi out about 10 seconds after superpilot's antics were complete.

I wrote in my now defunct freight blog about an experience I had with an experimental taildragger nearly colliding with a Cirrus in which I was instructing as we sat in the run-up area. The taildragger pilot was taxiing too fast and he didn't see us until the last moment. He caught my attention immediately when I saw the speed at which he was traveling, but by then we were a sitting duck - there was no time to taxi out of his way or evacuate the aircraft. The taildragger pilot saw us just in time, stomped on the brakes, planted his prop on the pavement, and slid to a stop just inches from the leading edge of our wing and our propeller.

Having flown taildraggers a bit, I imagined that the pilot's intentions were to enter the run-up area and swing the tail of his aircraft around, which is a cool and pleasing experience. But visibility while taxiing in many taildraggers is poor, at best. Taxiing fast in a taildragger might not be the height of stupidity, but it comes damn close.

When we got out and talked to the taildragger pilot, he seemed more concerned with the damage to his aircraft, engine, and prop than the tremendous fireball he almost created. No apology. No inquiry about us being okay, just concern over his own loss. What was his thought process? Did he have a little voice in his head telling him to slow down and he just ignored it? Or did it never cross his mind that what he was doing was inherently risky?

Most pilots taxi too fast and I myself have been guilty of this. In aircraft without GPS you usually do not have an objective measure of your ground speed. The airspeed indicator won't start providing indications until you are travelling 35 or 40 knots and by then, you are already going too fast. If you have GPS, pay attention to your ground speed while taxiing. My rule of thumb is to avoid taxiing faster than 8 to 12 knots in a light aircraft. I taxi even slower when near other aircraft, fences, or obstructions.

Keeping your groundspeed down while taxiing takes discipline and attention, as does keeping situational awareness on the ground or in the air. If you are a "brave" pilot I recommend that you consider what risks your heroic antics might pose to others. To do this, we must stop and think about someone other than ourselves. Based on what I've seen, this sort of thinking is in short supply.

Sunday, August 10, 2008

Complex Problems

The vast majority of pilots currently flying for the airlines received their training in a civilian setting, though that wasn't always the case. The usual route to the airlines is to earn your various certificates (either under part 61 or part 141), then decide whether to become a flight instructor or find another way to build the required hours to apply for a professional flying job. Some pilots become instructors and many of these folks provide quality instruction while building hours. Other pilots choose to build flight time through towing banners, flying traffic watch, performing pipeline patrol, or doing aerial survey work.

One thing that these U.S. pilots have in common is that they all earned a commercial pilot certificate and when they took that commercial check ride, it was in a complex aircraft, defined in 14 CFR 61 as an airplane that has a retractable landing gear, flaps, and a controllable pitch propeller or, in the case of a seaplane, flaps and a controllable pitch propeller. The problem is that finding a complex aircraft to train in is getting harder and harder. There are several reasons why this is the case.

There are only a handful of piston engine complex aircraft still being manufactured and the Piper Arrow the only complex trainer I know of that is still in production. Many large part 141 flight schools use Beech Bonanzas and some flight schools use twin-engine aircraft (more on this later). Otherwise, a potential commercial pilot candidate is left to choose from a selection of older Mooney, Cessna, and Beech aircraft that make up the aging fleet of complex trainer aircraft still in service.

One reason that few manufacturers want to produce a complex trainer is that many owners and operators know that maintenance and insurance costs are higher for retractable gear aircraft. And then there are those unintentional gear-up landings. New aircraft manufacturers like Diamond, Cirrus and Cessna (nee Columbia) rely on the simplicity and low operating costs of a fixed landing gear coupled with aerodynamically efficient airframe designs to sell aircraft. A fixed gear reduces the cost for periodic inspections, maintenance, and insurance, but it leaves aspiring commercial pilots, flight instructor candidates, and the instructors who train these pilots with fewer and fewer options.

Some flight schools and pilots get around this problem by earning their initial commercial or instructor certificate in a multi-engine aircraft, which allows them to do a single-engine add-on to that certificate in a fixed-gear aircraft. With the rising cost of fuel, this alternative is less attractive, but often the only option available. And guess what? The aging fleet of multi-engine trainers is in the same sorry state as the fleet of complex singles. Again, there is really only one light multi-engine trainer aircraft currently in production: The Piper Seminole.

One solution to this problem would be for the FAA to provide some relief by redefining complex aircraft for the purposes of training toward a Commercial Airplane Single-Engine certificate so that it includes certain fixed-gear aircraft with constant-speed propellers. This would vastly increase the number of available trainers, but I'm not sure anyone at the FAA is listening or willing. Without some sort of relief, the shortage of complex single and multi-engine aircraft will only worsen, leaving aspiring professional pilots out in the cold.

For another illustration of increasing complexity, you don't have to look any further than the G1000. I recently helped the owner of a G1000-equipped aircraft comply with a service bulletin that requires the testing of the Course and Baro knobs. Most everyone who does G1000 transition training wonders why the folks at Garmin designed the course and barometric pressure setting knobs so that they were concentric. These two functions, course and altimeter setting, have absolutely nothing to do with one another, so the reason must have been one of economics or the result of a committee decision.

Whatever the genesis, the design is really unfortunate and this particular service bulletin arose because some of these concentric knobs were failing in a subtle way: Setting the altimeter or adjusting the course in an affected G1000 unit could cause unwanted movement of the other setting. As my mom used to say "You've buttered your bread, now you can sleep in it."

If owning and maintaining a G1000-equipped aircraft weren't complicated enough, a recent instrument candidate I recommended was chided for not having memorized the model numbers of each and every component that makes up the G1000 system. This candidate was also told they should have known how each unit communicated with the others. My reaction was "Is this pilot supposed to demonstrate that they can fly a G1000-equipped aircraft or are they supposed to be able to fix it?" And where does this level of minutiae stop being useful? Is it sufficient to know that the units are connected with an ethernet network or should a candidate be able to describe the data packets that are exchanged, whether or not the packets are acknowledged, and what the bit ordering scheme is?

The FAA's flight instructor material describes four levels of learning, from lowest to highest:
  • Rote
  • Understanding
  • Application
  • Correlation

The various Practical Test Standards published by the FAA say that flight instructors are to train their candidates to the higher levels of knowledge - application or correlation. Memorizing the model numbers of the G1000 components is clearly the lowest level of knowledge, but it's also the easiest to test: You either know the letters and numbers or you don't.

Asking someone to explain how the various G1000 components play together would seem to be testing a higher level of knowledge, but on closer examination this is really of little use once you are airborne. When a G1000 component fails or misbehaves in flight, there is little the pilot can do other than maintain control of the aircraft, land, and let an avionics technician replace one or more of the pricey LRUs (line-replaceable units).

One thing Garmin could do to reduce complexity would be to redesign the G1000's MFD status display so that it would describe each LRU with a plain English name. Rather than demanding that a candidate know the model number of the G1000 air data computer, examiners could ask about real world scenarios, like what would your PFD look like if the air data computer failed.

If something isn't done to manage this complexity in an intelligent and useful way, pilots will be forced to learn more and more useless trivia and safety will be compromised. Some say that it already has.