AVmail: Aug. 29, 2005

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Reader mail this week about flying with a broken wing, better vision with shaded contact lenses and more.


Cessna Incident

Regarding flying without five feet of wing (NewsWire, Aug. 22) ...

The picture appears to be that of a P210. Five feet is an exaggeration since it appears from the photo that the aileron is intact and that surface extends to the tip.

With extended wingtips incorporating a fuel tank, such as those provided by Flint, at most the plane was missing two feet of its wing -- essentially just the tip tank.

Also with the damage shown, most of it would have been hidden from the cockpit. However, he pilot should have noticed the change in the downward curved portion of the tip.

Tom Cox


Electronic Flight Bags For GA

Brad Ellis raised a good point about electronic flight bags (AVmail, Aug. 22). His personal experience showed that they don't work under high-altitudes (i.e., low air pressure).

The problem is not in the hard drive; these are vented, mechanical units. He doesn't mention what brand EFB he was using when it failed, but if it had a plasma screen, that would be the problem.

Plasma screens are bright and high-contrast -- great for a sunlight environment -- and relatively inexpensive. But unless built for high-altitude, they'll fail to respond as the pressure drops. Restore the pressure and the display comes back.

Plasma TV manufacturers have special "high-altitude" units for mountain cabins and motorhomes. The same could be had for EFBs.

The glass cockpit in the new Cirrus and other planes use liquid-crystal displays (LCDs) instead of plasma for this reason -- they're unaffected by pressure changes (though LCDs do cost more than plasma).

Kirk Wennerstrom


Better Vision Through Shaded Contacts

I was very interested in the above article (NewsWire, Aug. 22), as I have worn glasses and contacts for 24 years.

Accordingly I posed these questions to the New Zealand Civil Aviation Authority Medical Team:

  1. Have you heard anything about this type of contact lens?

  2. Your thoughts on the suitability of type of lens.

I received the following reply from Dr. Claude Preitner, a respected CAA Medical Officer:

This is in response to your inquiry regarding tinted contact lenses.

Annex I to the Convention on International Civil Aviation specifies that contact lenses may be used to meet the visual requirements provided that the lenses are monofocal and non-tinted.

In view of this and considerations of the aviation environment and visual tasks, it is most unlikely that we would accept tinted contact lenses.

In response to your specific questions:

Question 1: Yes

Question 2: Not suitable

Given that the document referred to is an international one, I suspect that a similar view would be held by most aviation authorities and any pilot using this type of lens could find themselves outside of their license provisions and hence outside of insurance coverage in the event of an accident.

You may wish to follow up on this with your contacts in other countries.

Les & Jude McKendry


The Right to Flight

I fly into and out of the ADIZ and near the Flight Restricted Zone inside Washington Class B airspace. I know personally of the horrors and lunacy that this juggernaut of bureaucratic one-upmanship has created. There are no checks and balances, no quality assurance or QA measures in effect. Your online editorial is well-timed (ATIS, Aug. 25) ... perhaps the lack of response to the proposed legislation is the result of apathy from a group (aviators) that has been cowed into submission by government heavies (FAA, TSA, etc.) Until someone makes a documentary on television, it will be difficult to make this message more than a cry from the wilderness.

Rose Noyes


Dornier Do 24

In describing the visit of the Do 24 to New York, you said a similar seaplane came to New York in 1931 (NewsWire, Aug. 25). That visit was made by the 10-engined Do X. The first flight of the prototype Do 24 was in July 1937.

John Brindley


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