Letters: January 2011

Sunglasses Kudos

Good job on the research and info to rank this important pilot tool. I took a pair of G-15 frames and after having three pairs in a row of the glass lenses get damaged by my carelessness on the ramp, dropping off my face in 95-degree weather doing


a fuel sump, or oil check for pre-flight or something, I went to a custom progressive polycarb prescription lenses, which I also needed to be legal to fly IFR approaches looking at approach plates. They are tops. Plastic is great. Frame size, optics with a green lens color are very good and the true test: I can wear them for my longest trips; 4.5 hours in a Malibu without any temple pain.

I have also owned a pair or two of Randolph Intruders that were glass lenses and I believe one of the studliest frames around for jock pilots. I have just converted one pair to polycarb lenses and am just breaking them in. Randolphs customer service people are top notch. RayBan and Serengeti are hip, but Raymonds have the best choice in aviator-style frames for old school guys like me.

Jack Thorp via e-mail

What About 406?

I know both Spot and Spider well and your report in Decembers Aviation Consumer captures the essence of both of them. You also draw a sensible conclusion that they are apples and oranges and you get what you pay for.

But heres my beef with you on this. You parenthetically opened the question about whether 406 MHz ELTs are a worthy alternative or even an additional device intended to accomplish virtually the same task.

You hint that 406 is less than adequate in performance and you hint that sales of 406 ELTs have been weak. But this is not the Bertorelli who speaks straight talk and calls a spade a spade and provides solid facts and rationale for his conclusions and recommendations.

May I humbly suggest that you take on the obvious challenge to directly compare Spot/Spider with 406ELT? I have a hunch that you were simply teasing us as a precursor to an article next month that answers my question.

I see no significant incremental value in 406 so I will continue with my 121.5 MHz ELT, plus Spot or Spider. But the mandatory 406 requirements in Canada and Mexico place me in a jam because I fly across both borders.

In my view, Canada and Mexico have been duped into mandating 406 ELTs. Sure, they both have a grace period for U.S. aircraft, but that will soon end. If you believe in 406 ELTs, lets be reading your rationale! If I am missing something, I am all ears.

Jim Herd
via e-mail

Paul Bertorelli concedes he is but a shell of his former self but promises to take your request under advisement.

Inogen Oxygen

I read Marc Cooks article on the Inogen oxygen generator in the October 2010 issue with interest. An on-board oxygen generator (OBOG) seems like a good idea whose time may be here.

Two points to make: The article describes a flight at 13,000 feet and converts this to density altitude. Oxygen need is driven by pressure altitude, not density altitude. Its the partial pressure of oxygen that is important, not the density. So the tables column of 15,800 feet is actually 13,000 feet. The equipment doesnt look quite so good.

The second point is the use of a cannula which is simply not as good at delivering oxygen to the lungs. Id recommend repeating the tests with a mask and recalibrate the tables to pressure altitude.

Richard L. Newman
Lexington Park, Maryland

Awesomeness of Glass

With regard to your latest editorial about the value of glass in aging airplanes, I think there are a couple of more aspects to this whole new world. Im now in my sixties and Ive had my airplane for almost 17 years. In my wildest dreams, I never thought it would be what it is today. In my eyes, its practically an airliner.

If you had told me 10 years ago that all my approach plates would be on the panel and I would no longer have two mechanical vacuum pumps, I would have written you a prescription to ease your anguish.

And I never hear mentioned the hidden benefit of all this newfangled stuff: It brings instrument flying up to a whole new level by bringing the pilot right into the panel. My abilities are way better than before the glass. Know what I mean, Grasshopper?

At this point, my airplane is certainly the last one I will ever have and Im as pleased as punch about it. When I add on another goodie, I dont think about how much it will be worth when my wife sells it at estate. I think about how much fun my next trip to Atlanta or Chicago will be.

Brian Peck, MD
Waterbury, Connecticut

More iPad

I just finished reading your article on the iPad and agree that its a terrific digital chart replacement. I have been using Foreflight and like it despite my Jeppesen upbringing. Foreflight or WingX on the iPad is just too easy and cost effective to use anything else.

My one big concern comes from what to use as a backup. iPads have been known to quit in the cockpit from overheating or other reasons, so a backup plan seems prudent.

I carry an iPhone with Foreflight loaded. I bring a paper enroute chart and print approach plates for departure and arrival airports from the Web. For a long flight, I also bring plates for an intermediate and diversion airport. I feel this is adequate (perhaps overkill?), but was wondering what your thoughts are on appropriate backups for the iPad and if you think theyre necessary.

David Landset
via e-mail

We think the likelihood of a critical iPad failure is low. If that does happen, paper charts are adequate backup.

Weve heard from a number of readers who experienced iPad failures due to overheating, but it appears that this can be avoided by simply keeping the device out of direct sunlight. We recently saw one failure due to a dead battery, something you cant directly address in the cockpit without an external power source.