by
Darryl Phillips
Let me tell you a personal story. When we founded Airsport Corp. seven years ago, our first product was a very simple little altitude alerter called the Altitude Nag. It was designed to connect directly into the Mode C encoder, so wiring was a matter of simply plugging it in. The control head was the size of a large postage stamp. It had a green button for on/off, and a yellow button to set altitude. The pilot climbs to altitude, then presses the set button. If he deviates outside that 100 foot increment of altitude, the button flashes and the horn beeps.
The Altitude Nag advanced the cause of safety. We sold hundreds to the experimental market, and thousands to the certificated market. Many were installed sans paperwork I suppose, and many were field approved. None were approved in the fsdom of Teterboro, of course, because Teterboro has very strange requirements.
(The next time somebody says it's necessary for aviation to be regulated nationally, ask them why each fsdom has it's own rules. Rules they refuse to publish. Ask them why it's perfectly safe to install something in Boston and fly to Teterboro, but illegal to do it the other way around. Ask them why a Minimum Equipment List must be cancelled when the equipment doesn't change, and the plane doesn't move, and the ownership doesn't change, but the owner moves across the river into a different fsdo district.)
Of course we wanted to gain TSO/PMA approval for the Altitude Nag. Technical Standard Orders (TSO) exist for most items from compasses to seat belts. Parts Manufacturing Authority (PMA) is approval the factory must have to produce TSO'd equipment. In many cases, TSO approval isn't required for equipment installed in Part 91 aircraft but this is subject to regional interpretation, so it's nice to have TSO certification.
Unfortunately, there is no TSO category for altitude alerters although at least four avionics companies make them. So no TSO approval was possible. Next best was a Supplemental Type Certificate (STC). STCs are issued for installations in specific aircraft types. Usually after a piece of avionics has been STC'd in one airplane the approval in others is easy. Usually. But approval varies between fsdoms, and is subject to the whim of the individual inspector.
The FAA engineering office in Fort Worth assigned an "engineer" to work with us. He laid down a number of asinine criteria. For instance, since our unit plugged into the encoder, we had to STC it in an aircraft that required an encoder on it's Type Certificate.
I'd planned on using my Tomahawk, it's clean both physically and paperwork wise. The "engineer" refused because the Tomahawk TC does not require an altitude encoder! Ditto for the 182 and a couple of Bonanzas that were available to me.
As near as I can tell, there are NO general aviation airplanes that require an altitude encoder on the aircraft TC. Type Certification involves airspeeds and strength of materials and other things that keep the plane flying. On the other hand, flight rules found in Part 91 require things like transponders and encoders and other black boxes that keep ATC happy.
The encoder TC requirement was only one example of many. It was obvious that this "engineer" (1) knew nothing about light aircraft, (2) cared nothing about aircraft safety, and (3) wasn't about to put his signature on anything. In our final half-hour phone conversation, I managed to hold my emotions rather well until I hung up the phone. Then I picked it up and slammed it down harder. And harder, and harder. Soon little springs and buttons and bits of plastic were flying around the room. I sat there and totally destroyed that phone, I was so damn angry.
(We shall see if some FAA type reads this and seeks to have my medical revoked because I'm mentally unstable, like they did to Alaska pilot David Mahaffey, who told a reporter that he always thought of his 16-year-old son when he flew over the son's grave in the cemetery adjacent to the airport.)
The federal pay and benefits are the same whether an FAA "engineer" checks the YES box or the NO box. Why should he stick his neck out if there's nothing in it for him? This is the perfect setting for bribery to develop, and it certainly doesn't improve safety. But from the perspective of the individual bureaucrat, the NO box is much safer.
So when you mourn the cost of certified aircraft parts, have a little sympathy for the producer who must deal with the FAA.
The Altitude Nag never was approved. In it's place, we developed a better box that requires no connection to the aircraft at all. It receives everything the transponder is reporting to ATC, and gives the pilot a lot of useful information. And it's an altitude alerter too. It has been on the market for five years and is flying worldwide in everything from single place homebuilts to Citations and Westwinds.
About a year ago I was approached by a well known avionics wholesaler to design and produce a box to connect the GPS to the other equipment. When an IFR-certified GPS is installed, it is connected to the existing nav head or HSI. Some means must be provided for the pilot to switch between ILS and GPS. Installers are free to use any combination of switches and relays and indicators. They can wire them up anyway they want, and locate them however they see fit. Every installation is unique. Often a schematic diagram isn't even drawn, and this is totally legal. It's even legal in the fsdom of Teterboro.
The avionics company wanted a little device that would make the installer's life easier. This box would provide all the annunciators, switching, and fail-safe provisions in a single attractive package. I was told no approval was necessary. I chose to no-bid the project, it was obvious that even if FAA approval wasn't necessary that day, it soon would be. Given my proven inability to deal with the feds, I didn't wish to pursue it further.
Sure enough, FAA now says that such switch boxes must be approved. It makes sense - not only because the GPS signals might be compromised - but likewise the ILS information goes thru the box as well. If it were to fail it might conceivably leave the pilot with neither GPS nor ILS.
But how to certify such a box? There is no TSO. In the meantime, thousands of installations must use whatever cobbled up collection of switches and relays and lights the installer has at hand. It seems obvious that this situation is more hazardous than a box designed for the purpose and proven successful in other aircraft.
Now, approved boxes are beginning to appear on the market, certified under TSO C-129. This is the GPS TSO, but the switch box is not a GPS. Not in the wildest imagination could this passive device be called a GPS. It is essentially a switch in the VOR/Localizer line. So why not approve it under the TSO that covers VORs? That is a much older TSO and would be easier to meet.
But the switch box isn't a VOR either. It is a simple piece of passive equipment, and deserves a simple TSO. In the interest of aviation safety it deserves it NOW.
In the meantime, the legal haywire installations are continuing and they are being used in IMC approaches, the most critical phase of flight. This is a typical example of the disconnect between FAA and safety.
Where do TSOs come from? Since they are FAA documents, one might be naive enough to assume they come from the FAA. That used to be true, but in recent years the bureaucrats we pay to do this work haven't been doing it. The full story leads us to RTCA and MOPS and other nasty things.
If you'd like to hear more about the reproductive system of the TSO, let me know. I'll try to treat the subject in a manner befitting a family newspaper.