Letters: 12/01

Pump Pros and Cons
I want to encourage the FAA and/or the NTSB to institute a change in the instrumentation of small-airplane vacuum systems so that a vacuum failure is more survivable in heavy instrument conditions.

Having watched the ABC Prime Time Thursday report on 9/3/01 and having had two vacuum pump failures myself, I understand the problem. I think that the solution could be very inexpensive.

There should be no need for a potentially failure-prone back-up pump but a warning to the pilot that there has been a failure. Currently, the vacuum pump pressure gauge is the smallest indicator on the panel and is we’ll out of the scan pattern.

If an additional indicator were placed in the gauge, the element of surprise would be minimized. Currently, such a marker is used in most modern cars to indicate low remaining fuel. This indicator could be a bright red LED mounted in the gauge.

The sudden presence of a bright red light should cause the pilot to recognize the loss of pressure. There would be an automatic self check before engine start and no new connections or firewall penetrations would be required.

-John Davis
via e-mail


Like most pilots, I was dismayed by the over-dramatization of the ABC news report on vacuum pump failures. However, I am also worried that the upbeat report in Aviation Consumer (Partial Panel: Would You Survive?) could lead to complacency. The truth probably lies somewhere in-between the two reports.

Earlier this year I solicited stories from pilots who have experienced actual loss of vacuum and/or gyros in flight. The results will be published in the December issue of Flying. Most of the pilots who wrote to me about their experience would not agree its reasonable to conclude that any pilot who trains periodically in partial panel should be able to complete an approach, even in low weather.

They were amazed at how disorienting the failed instrument(s) were, and emphasized how important it is to immediately cover up the failed instrument(s), to declare an emergency, to explain to ATC the nature of your problem, and to keep things as simple as possible until you are safely back on the ground or in good visual conditions.

I encourage anyone who has a further interest in this subject to read my article on Surviving A Loss Of Gyros in the December issue of Flying.

-Jay Hopkins
Contributing Editor, Flying

We wouldnt call our report upbeat so much as realistic. The fact that those who responded to your survey are still alive supports the contention that vacuum failures are largely survivable, albeit occasionally terrifying.


iPAQ Navigation
Good article about the Anywhere Map in the October issue. Your down points about the iPAQ plug and the direct button not working correctly are right on the money. Anywhere Map assures me they will have the direct function bug fixed in Octobers software update.Also, they say they have a prototype made for a fix on the iPAQ plug. we’ll see.

Your other down point was the lack of battery power in an emergency. I went to Radio Shack and bought one of their plastic eight-AA battery holders and connected one of Radio Shacks female cigarette plugs to thebattery pack.

It works great out of the airplane and the eight AAs last a long time as the GPS and iPAQ don’t take much current.

One way to get rid of the cabling problem and cigarette plug is to cut the cable and wire a DB9 pin plug in the panel and wire the bus voltage to the plug through a 1/2- amp circuit breaker for the GPS and iPAQ.

Then wire in the iPAQ end of the cable to the mating DB9 pin plug. I put a 1/4-inch hole through the glareshield with a grommet and ran the GPS/antenna cable through that so nothing shows but the short cable from the DB9 pin panel plug to the iPAQ. Next on my list is the Icarus solid-state attitude indicator running on the iPAQ with the weather function in stand-by.

-Dick Welsh
via e-mail

After we published our report, Control Vision told us that Sportys Pilot Shop sells a version of the iPAQ with a battery pack that will operate the navigator in emergency mode.


Hes Surprised
I was very surprised to find that the article on six-place singles completely ignored the Cessna 206/T206/210. As a former owner of a 210 and currentowner of a 1999 Turbo 206, I think that the 206 is a competitive entry in the six-place market.

Before we bought the T206, my partner and I test flew both the Bonanza and Saratoga. We ended up buying the T206 for several reasons: The pilot/co-pilot seating area is larger and more comfortable in the T206 than in either the Saratoga or Bonanza.

Neither my partner, who is 6-feet-7 inches, nor myself, could get comfortable in either the Saratoga or Bonanza particularly because of the limited head room and leg room in these airplanes due to the placement of the main spar. Passenger seating for four is generous and for six, no less comfortable than the seating arrangement in the other airplanes. With the large double rear doors, access to all seats is no problem.

The airplane has a better useful load than either of the tested airplanes. We opted for the Flint tip tanks which increases the useful load by 180 pounds, to just about 1500 pounds useful load. CG loading is not a problem, and endurance is now more than five hours with the 118 gallons available.The airplane turns in a respectable 150 to 155 knots down low and 165 to 170 knots at altitude. Better than the Saratoga although not quite a equal to the Bonanza and with big strong fixed gear that are hard to damage.

The cost of the airplane is $100,000 less than the Saratoga and a lot less than the Bonanza. Having flown all the above, I can honestly say the airplane handles very well, certainly the best of any of the Cessna singles and equal, in my opinion, to the tested airplanes.

Maintenance cost is generally lowest with Cessnas and our dealer/factory support from Lincoln Park Aviation and Steve Kent, the regional factory rep, has been excellent. All in all, maybe not as sexy, but an excellent six-place machine.

-Sy Fertig
Via e-mail

The Cessna 206/210 series offer six seats but they arent cabin class. And thats what the article was about, as we explained in the introduction. We published a general six-place comparison in the January, 1999 issue of Aviation Consumer. Our view is that there’s a clear difference between the club seating option of the Cherokee Six and the Bonanza 36 series and the Cessna 210.


HSI Feedback
I read the August 2001 HSI flyoff article with interest since I am having to put one in my airplane. As it turns out, I have a choice of a Century NSD360A reman non-slaved for $3200 or a new slaved NSD1000 for $5200.

Im way more concerned about reliability than money, but not enough to buy a Bendix/King unit. The article claims that 360As are more reliable than the 1000s.My avionics guy had no corroborating reports so he called Century.They claim the parts are exactly the same except for the gyro itself and that reliability is way up in the last four years.

Im wondering if the data points cited in the article were low serial numbers and if things have gotten any better lately.Do you have any more recent info?

-Colyn Case
via e-mail

The latest information we have comes from a handful of Cirrus SR22 owners who reported premature failures of Century 1000 HSIs. Other reports from the field tend to confirm this. We still think the NSD 360 enjoys the reliability edge.


A couple comments on the Bendix/King KCS55A HSI and KG102A companion slaved gyro. I have had two different sets of this very good system. One was circa 1977 and the most recent circa 1993. The earlier version had a deceptive failure. The compass card would stop turning in a right turn with no HDG failure flag. If the direction of turn was reversed, the heading card would begin turning again.

This was an intermittent thing and took several failures of this kind to deduce exactly what was taking place. A very astute technician opened the KG102A and found a plastic disc-a segmented disc that the gyro utilizes to determine the degrees of turn-had come loose from a metal ring to which it is attached.

Being loose allowed the ring to drag on something inside the gyro and stop the disc/ring from turning. That action was interpreted by the system to mean that the turn had stopped and the heading card in the HSI ceased moving.

No malfunction was sensed by the system, so no HDG failure flag appeared. We decided to attempt a fix whereby the tech would use epoxy glue to re-glue the disc to the ring. I flew that system several more years before selling the airplane and the problem never recurred.

The KFC200 system in that airplane was one of the early ones and I would hope that the KFC150 in my present airplane has been upgraded to catch and display a HDG failure flag in this kind of failure scenario.

-Bill Pappy
Southlake, Texas