Letters 05/99

GPS Costs
I have a question about GPSs that I was hoping the staff at Aviation Consumer could help with. Ive been looking at handhelds and wondering why the aviation models are so much more expensive than the similar sports models. The Garmin GPS III, for instance, sells at the sporting goods stores for around $300, while the GPS III Pilot is in the $650 to $700 range.

In reading through the documentation, the only difference Ive seen is that the aviation models accept Jeppesen databases and allow for database updates, while the geographic databases in the sports models are not changeable.

Which brings me to my second question. Do you have any experience with add-on software that takes the output from the GPS and uses it to interpret mapping data? Im thinking of the Flying Pilot software from GPS Pilot, at http://www.gpspilot.com/. If Im going to spend $700, it would be nice to also get a Palm Pilot for the money.

-Jeff Cours
Via e-mail

Weve asked the same questions and have been told that the aviation database is the single largest component in the cost of an inexpensive handheld GPS receiver. Reading between the lines, we have to guess that accessory packages-yoke mounts, and so on-tend to elevate aviation GPS costs, although Garmin introduced the GPS III Pilot with a stripped down accessory list.

Although the market is intensely competitive and price sensitive, we don’t doubt there’s a degree of market-will-bear pricing in the handheld market. After all, pilots expect to pay more. We havent tested the GPS Pilot software we’ll look into it.

FliteStar Beefs
With reference to Jeppesens announced lack of support for the Macintosh format for FliteStar, I would like to also voice my disappointment as one of the original users of the Macintosh FliteStar program.

It is true that both FliteStar and JeppView run quite we’ll on a modern Power PC Macintosh (especially the G3) using Virtual PC. The only bottleneck seems to be printing. Unfortunately, the program just seems better on the Macintosh than it does on the PC, as is often the case. For a Mac user, running it on a PC is a definite step backwards.

Jeppesen has advised me that they are receiving many complaints from Mac users and I would urge your readers who prefer the Macintosh format to voice their concerns to Jeppesen. While Macintosh may only represent 3 percent of their recognized market, its growing and obviously many users like me are reluctantly running the program in the PC format.

-Howard A. Tobin
via e-mail

To be perfectly cynical about it, any upgrade in software or hardware involving a PC-based machine is a step backwards, in our view. The damn things just don’t work worth squat.

However, even though the Mac is a superior machine, Jeppesen and other companies tell us that its aviation market share is dwindling, not increasing.

I enjoyed your article on the electronic logbooks and just thought I would let you know that I have been using AerologIII since early on in its over-the-counter edition.

The latest version I have is V3.2 and I am very happy with it. I consider AerologIII as my primary logbook, even though I do keep a written log also. But I make sure I have good back ups, which happen to be a snap with this program.

I was also very interested in the latest oil argument, which in my opinion makes a lot of sense. I noticed you did not have any comments to Mr. Franks argument, but can you clarify who he is and if his comments are worth paying attention too.

-Name withheld

John Frank is director of the Cessna Pilots Association. We frequently consult CPA for questions on Cessnas and find the groups technical information to be superb.

As for the oil argument, it rages on. Our view is that the subject is so muddled with opinion, anecdotal evidence and flat out propaganda that it may be impossible to reach accurate conclusions about oil choice.

Franks view is that its better to use straight-weight oil if the aircraft wont be flown for a week or more in areas of significant climactic change or in warm weather where a multi-weights lower viscosity characteristics arent needed for cold starts.

The chief issue continues to be long-term corrosion protection. Critics of multi-weight argue that it offers less protection than straight-weight oils do, due to lack of film retention over time.

The oil companies-chiefly Shell and Phillips-argue that lab and field tests reveal just the opposite. we’ll have more to report in a future issue.

Telex ANR Fan
Some months ago, Doug Ritter wrote an article comparing various models of ANR headsets. He commented that the Telex ANR-1D was something of a disappointment. As a happy user of that set and having compared it to a number of others, I wrote a letter of disagreement with several points that you were kind enough to publish. While I agreed that the unit suffered from some minor flaws, I still felt it offered the best results on the market.

Over the Christmas holidays, I ordered a second Telex ANR-1D headset. I was surprised that I was unable to get immediate delivery. Apparently all dealer stocks had been sold and there was a shipment delay on re-orders from Telex. I finally received the headset in mid-January. When I started using the new headset, I immediately noticed some differences, all of which seem to be improvements over the original set. For one thing, an occasional clicking noise apparently caused by audio distortion was gone.

The performance of the new headset was significantly better than the original in dealing with propeller noise. The response is quicker, deeper and generally rather more solid. Its still interesting after a throttle change to note the ANR circuitry partially loses its digital lock on the noise for a second.

Over a period of perhaps two more seconds, it works out the needed correction and applies it, making the residual propeller noise virtually disappear. In any case, the amount of attenuation of propeller noise is remarkable in my opinion, even with the pilot window open.Another very nice improvement is the considerable reduction in white noise when the ANR set is active and there’s no competing noise. That also means less white noise when used in flight. I compared the audio fidelity of the earlier version of the headset with the later one when playing music. The new headset is better. It still is not quite as rich in bass notes as I might like, but then considering that the headset is designed to eliminate most bass noises, especially propeller noise, I do consider that a very acceptable tradeoff.

After some flying with the new headset, I called my contact at Telex and asked him what had happened. He congratulated me on being among the first to get the new version of the headset. He told me that they had started manufacture of the new version but inventories of the earlier version had run out before new shipments began, so that there had been backorders during the Christmas holidays.

It seems that there has been a considerable amount of work done to update the ANR-1D to remove any remaining flaws. I asked about the things I had noticed and was told that all of them were items that had been worked on. He was particularly delighted that I had noticed the reduction in white noise. He had wondered if anyone would pick up on that. The Telex rep told me that that it was not economically feasible to upgrade earlier versions of this headset.

In sum, I think the new version is a significant upgrade over the original headset. Frankly, I don’t understand why they don’t toot their horn a bit on this and assign a new model number. In any case, I urge you to revisit the product. I think you will find it a very worthwhile addition to any airplane.

I have no financial connection with Telex and indeed compete head on with another division of that company.

-Bob Locher
via e-mail

UAG Correction
Good article on stepping up to a six-place airplane in the January issue, but one error: The change-over on the A36 Bonanza to the 300-HP IO-550 and the new instrument panel occurred with the 1984 model, starting with serial E2111.

-Jim Scott
Wilmington, Delaware

Encoder Additions
I enjoyed reading your article about altitude encoders in the December issue of Aviation Consumer. However, I would like to bring a few inaccuracies to your attention.

To begin with, the altitude transmission code is a nightmare that began in the 1960s. Its an 11-bit code, not 9 bits, as you reported. It provides altitude information in 100-foot increments from -1000 to +126,000 feet, not -1000 to +408,600 feet.

You will find this code in ARINC 532. The confusion over this code goes back to the beginning of the military IFF program. In the early days, only 1000-foot increments were encoded.

When the powers that be decided to shift to 100-foot increments, they did not scrap the original code but merely tacked on a 3-bit series to account for the 100-foot increments.

Later in your article, you refer to ACK as one of the first companies to concentrate on encoders. I have to differ with you on that point. Litton Industries began making encoding modules for Kollsman altimeters in the 1960s. Trans-Cal has been making encoding modules and digitizers since 1973.

We were the first company to design and manufacture a digitizer, even before Narco got into the business.

-Hugh Smith
Trans-Cal Industries
Van Nuys, California