Letters: 04/02

Bruces Covers
My experience with Bruces covers is different from that which was reported in your article on cabin covers in the February issue.

I purchased covers for a 1981 Dakota and a Mooney Ovation and both have a cabin door flap that seals we’ll with Velcro. They also had snaps and straps and the location of the snaps in the front was adjustable to insure a good fit.

The material was light in weight and not bulky and there’s a fabric case that stows easily in the back half of the hat rack area of the luggage compartment.I don’t think you did Bruces covers justice.

-Josh Duncan
Cumming, Georgia


Oximeter Accuracy
While reading your February issue, I came across Edward Barrs comment about the inaccuracy of pulse oximeters.

A good friend has pulmonary fibrosis and has an oximeter to monitor his SpO2%. He was in the hospital this weekend so we looked at the differences between his unit and the hospital monitoring device.

We tried each finger, putting the devices one way and then the other. The only difference was 1percent while up in the high 90s and at lower ranges the numbers were exactly the same. If that is inaccurate Ill take it!!

-Ernie Ganas
via e-mail


Cheap to Keep
I read the above article in your February issue and wondered about your treatment of short-wing Pipers. I think you misjudge them.

In the pattern knock-about category, you should have included the PA-15/17 Vagabond instead of the PA-20 Pacer. The Vagabonds are more similar to the others than is the Pacer. Its inclusion in the knock-abouts is not fair to its capabilities. The Pacer is the only four-seat airplane in there and its definitely faster and hauls more than any of them. Its more like a Cruiser in its capabilities.

You seemed to mention the TriPacer in a sort of offhand way and other than the fact youre not that familiar with it, I don’t know why. Especially in its most common 150 HP version, from 1955 on, its faster and carries more than the early 172 Cessnas.

I know, I own one that is fairly stock and its faster and carries more than the O-300 172s. I know from experience it outperforms the PA-28-140 at about half the price.

Curiously, the PA-28-140 is your first choice, but I could almost buy two Tripacers for the price of one 140 and it performs better on the same reliable O-320.

-Tom Lubben
via e-mail


TPAS Rebuttal
We do not feel your article in the March issue of Aviation Consumer fairly addressed the role of our TPAS collision avoidance system, nor its capacity to fill that role.

It is first priority to note that model reviewed was our first model, theRX-100. Many of the issues mentioned in the article have been addressed with the release of our new TPAS RX-110.

We have also recently renovated our customer service, including hiring additional staff, expanding our facilities to accommodate more employees and inventory and, most significantly, removing a third-party distributorship, allowing us to work personally with our dealers and customers.

Most pilots cannot begin to afford the $6000 TCAD, let alone a TCAS, if they even have an airplane of their own in which to install one of these systems. TPAS (and obviously the ATD-200) was never designed to replace a TCAS system, or to even compare. It rather provides an affordable option in basic traffic detection (not pin-point location) for the average pilot, with a particular mind to accommodate the commonly overlooked renter.

When our device does not receive a proper signal, no basic function will appear to operate properly. It appears from your articles photo of the units in flight that our TPASs antenna was not positioned vertically. Consequently, many features are not accessible or predictable, including traffic detection and suppression.

We are not alone in this scenario. According to an article published by FlyingSafely.com regarding the ATD, When airborne… the unit sometimes reported traffic nearby repeatedly with all the lights going. I was unable to confirm any traffic during these numerous alerts… I called the manufacturer… [who] explained to me that… if our transponder signal was not strong enough the ATD would think it was traffic nearby, and what we needed to do was move the antenna where our transponder signal would be stronger.

We received no phone call to discuss any potential problems with reception, which could have been quickly remedied with a simple repositioning of the antenna. Moreover, these collision avoidance systems are not designed to work in the presence of other collision avoidance systems (i.e. testing the TPAS-100 and ATD-200 side-by-side).

Satisfied customers provide more valuable and realistic tests than those in a controlled environment: TPAS detects targets and coverage areas in a consistent manner. Interpreting the returns is easy. It definitely gives one a heads up frame of mind in areas where complacency and boredom could lead to a life threatening situation. -John Wiser

[While] flying… at 11,000 ft, I didnt expect to see much from the TPAS… I just noticed that the unit was reading 5 miles… 30 minutes of monitoring the unit, it still said that there was traffic 5 miles… I asked the controller if he would verify… Sure enough, there was a Bonanza 5 miles in trail of us on the same airway, same altitude. Im hooked! -Thomas Johnson

There are reasons for TPAS larger size. Most airplanes do not have operable cigar adaptors and the FAA limits their use. (14 CFR Part 39/Amendment 39-3428; AD 79-08-03 & 79-20-07.)

Therefore, TPAS can operate over 11 hours on AA batteries, an option not available in the ATD-200, making TPAS a truly portable unit.

Batteries require space, as does a more complex circuitry. As pilots ourselves, we elected to incorporate a 2-true-mode system for greatest alert benefits. TCA mode assumes you to be slow yet close with other aircraft. Resolution in traffic distance is increased and conditions which trigger audio alerts and visual alerts are scaled to this environment.

Enroute mode assumes you to be faster and more spread-out, giving further distance resolution, thereby affording more time to react in a head-on situation. TPAS also features two distinct radar environment indicators, allowing you to determine whether or not you are within radar coverage, an important point that the review left out.

We welcome anyone to contact us for more information, demonstrations or questions. Please visit our website at www.surecheckaviation.com.

-Jason Clemens
SureCheck Aviation


Just read the article about the two inexpensive collision avoidancedetectors in the March 2002 issue of The Aviation Consumer. I have used a Monroy ATD-200 unit now for approximately 18 months and have been pleased with its operation and generally agree with the comment of your author. However, the operation of the unit is improved with panel mounting with an outside transponder antenna.

My unit is mounted in the center radio stack of my 1994 S35 Bonanza panel. It is connected to a bottom-mounted Comant CI-102 transponder antenna and the units warning audio output was connected into the Bendix/King KA-134 Audio Panel.The outside antenna allows for a much more consistent range response compared to the use of the rubber ducky antenna when used as a portable system sitting on top of the glareshield.

The bottom antenna location means that threat aircraft located below me are detected earlier than threat aircraft located above me but that choice seems best with a low wing aircraft, which makes visual detection of aircraft below a challenge.

The best option is to use two antennas, one on top and on the bottom of the fuselage. This would require that an appropriate coupler be used to divide the received signals into the units RF input.

For a pilot who owns his own aircraft, the permanent installation is preferred. However, the company has not made that option easy because first this product is not TSOd and second, the company does not provide a FAA Supplemental Type Certificate, which would make ongoing installation easier to get FAA approval.

The only option available to the owner is to apply to the FAA forfield approval of a proposed installation via the FAA Form 337 process. It took more than six months working with the FAA FSDO office in Des Moines to get my approval. Aircraft owners willing to try this process can contact me about getting a copy of my approval, if desired.

-William Hemme
812 Elmwood Drive
Spencer, Iowa 51301