Unicom

October 2002 Issue




Unwary Taxi Driver

Even a familiar airport can bite a pilot who isn’t absolutely sure the airplane can make it

Thanks for “Taxi Smack,” your excellent piece on taxiing accidents (Airmanship, August). I am a 2000+ hours pilot with a CPL/IR. One of the milk runs I make in my Mooney goes into Zurich, Switzerland, an airport I know well.

Some months ago, the authorities at ZRH decided to redesign GA parking, although no new taxi plate was published. Upon arrival I was assigned a familiar row and guided in by a follow-me van. When departing two days later in perfect weather, I got my IFR, startup and taxi clearances and taxied out in the normal fashion, turning left on the taxiway leading to the apron.

Within 100 meters I found the taxiway to the main apron was temporarily closed and a new lane for ground vehicles had been created where I was taxiing. Several construction trucks were headed toward me. I tried to do a 180 turn but space wouldn’t allow it so I advised tower, shut down, turned the aircraft on its towbar, started up again, and got a new taxi clearance.

With a queue of vehicles behind me, and while taxiing in the opposite direction, I missed the correct turn and caught my left wing tip on a post.

What should I have done? Upon encountering the unexpected I should have called Tower and asked for precise instructions – unlikely given the volume of traffic – or asked for a follow-me van. It was a clear case of tumbling dominoes, and the results involved a month of down time for the aircraft, a very large repair bill and much correspondence with my underwriters.

When in doubt on the ramp or taxiway – even in perfect visibility – ask for help.

-George Irvin
Brighton, Sussex, UK


Ouch, that hurts. We were spared a similar experience only by luck. The bright flashing of the wingtip strobes off a portable toilet made it painfully obvious just how close a call it was.

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’Scuse me?
So what is/are “sferics” [Weather Tactics, August]? Is this a Strikefinder type of device?

-Joel Baillie
Via e-mail


“Sferics” is a shortened term for “atmospherics,” which are natural radio frequency emissions in the ionosphere caused by electromagnetic energy radiated from lightning. Those radio emissions are detected by Strikefinders and Stormscopes, which compare the signal to model discharges in the unit’s software, then plot the storm’s bearing and distance.

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Good show
I’ve been a subscriber to Aviation Safety for many years. I’m delighted that it is now on-line!

-Robert Ovanin
Via e-mail


Thanks. We’re pretty happy about it, too. We’ll continue to augment the site and welcome any suggestions you may have on how to make it more useful or user-friendly.

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Spin from a Slip?
I was surprised to hear your comments to “Sudden Silence” [Learning Experiences, August], where a pilot stated that he held opposite rudder in a turn to help prevent a spin.

You state that “cross-controlling the airplane with right rudder in a left turn ... is an invitation to a spin.” Left aileron, right rudder sounds like a simple slip to me, certainly not a dangerous maneuver. If he were using excess inside rudder (skid), I would have understood your comments.

I cite Barry Schiff from Proficient Pilot, Volume 1, Chapter 9: “If the skidding turn becomes sufficiently aggravated, it may lead to a low-altitude spin ... (but) a slip poses no such hazard. If an airplane in a slip is made to stall ... the aircraft may tend to roll to a wings-level attitude, but that is about it. In some aircraft, stall characteristics are improved.”

-Robert Dant
Via e-mail


While we have the utmost respect for Mr. Schiff, we have to take issue with his statement. A slip during descent is usually OK because the airplane is descending, which helps unload the wings. However, a slip can lead to a spin if the pilot allows the airplane to roll toward wings level while continuing to pull aft on the yoke until a stall results. With opposite rudder in place, a wings-level stall leads to a spin entry. A detailed discussion can be found in the July 2002 issue.

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AC, AC, Wherefore Art Thou
I have been unable to find AC 61-67C, Stall and Spin Awareness Training, mentioned in Rich Stowell’s article “Recovery Room” [Stick & Rudder, July] on the FAA’s web site. Do you have a link to the new “C” release? The FAA site only shows “B”.

-Matt Majka
Via e-mail


Go to http://av-info.faa.gov/dst/ACreference/060-067.htm and you’ll find the AC about a third of the way down the page.

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Gimli Glider et al
I think Chip Wright needs to check the facts on his assertion that the “airlines never run out of gas”, presumably in normal operation.

-William S. Lyons
Via e-mail


While it’s true that airliners do occasionally run out of gas, it happens seldom enough that the statement is clear hyperbole – especially when compared to the woeful record of general aviation.