luminum and steel don't mix; at least they don't in a Lycoming O-290-D2 engine according to the Federal Aviation Administration (FAA). As outlined in the article "Never Buy An Orphan" in the July/August 2000 issue about never buying an orphan airplane, airworthiness directives (AD's) are another important item that can surprise the unwary new aircraft owner. AD's can cost a new aircraft (or an old aircraft) owner a lot of money if the buyer purchases an aircraft with a pending AD or AD's unless the buyer discounts the cost of compliance when agreeing to the purchase price. These are some of the things I didn't think about when buying my new toy since I was told this particular AD didn't apply. The bad news was the Orphan's engine was one of those "bad" engines. The AD did apply, and, no, I didn't discount it. I am a slow learner. But like buying a cute new puppy, what are a few fleas or AD's among friends. As I am quickly learning, "It is only money."

AIRWORTHINESS DIRECTIVES

For those who are not familiar with

airworthiness directives (AD's), they are contained in FAR Part 39, titled, Airworthiness Directives.

Arguably one of the shortest FAR parts, Part 39 can be one of the most expensive FAR safety related parts both in terms of cost, time, and, for commercial operators, lost revenue. About a half page in length, Part 39 provides FAA a method to alert aircraft owners and operators of, as stated in FAR $39.1, "(a) An unsafe condition exists in a product; and (b) That condition is likely to exist or develop in other products of the same type design." Then in $39.3, General, it states "No person may operate a product to which an airworthiness directive applies except in accordance with the requirements of that airworthiness directive."

Subpart B-Airworthiness Directives then states in FAR §39.11, Applicability, that "This subpart identifies those products in which the Administrator has found an unsafe condition as described in FAR §39.1 and, as appropriate, prescribes inspections and the conditions and limitations, if any, under which those products may continue to be operated."

Did I mention that FAR $39.1, Ap

plicability, says, in part, that "this part prescribes airworthiness directives that apply to aircraft, aircraft engines, propellers, or appliances (hereinafter referred to in this part as 'products') when-(a) An unsafe condition..." as noted above is found. As you can see, an AD can apply to all the good aircraft "stuff."

The above is basically all there is to FAR Part 39. However, the impact of these few words can ground an entire world-wide fleet of U.S. registered aircraft. As with all safety issues, since aviation is so global and interdependent these days, an airworthiness directive issued by one government may quickly impact those types of aircraft operated by other nations worldwide. In many cases, the release of a major AD has been coordinated between the various civil aviation authorities around the world before the official announcement.

Although not on the same scale as an AD affecting a fleet of air carrier aircraft, there were two outstanding AD's that applied to the Orphan. I knew about both. I just didn't realize how expensive compliance with both would eventually become. One AD in

volved the lift struts on all high-wing Piper aircraft. Several years ago, a Piper high-wing aircraft suffered an inflight wing failure because of corrosion in one of its lift struts. Since then, FAA has required a periodic inspection of all such struts, or to avoid the repetitive inspections, owners could replace the vulnerable struts with FAA approved replacement struts that effectively eliminated the required detailed inspection.

Inspection and replacement are two of the typical ways owners/operators can comply with many AD's. Other AD's may require only a onetime inspection. Others may require some type of repetitive inspection based upon flight hours, time, number of flight cycles, or other means of determining usage and wear. A common way to comply with many AD's is to replace the affected part with another FAA-approved part. Such was the case with the Orphan's lift struts. The previous owner had replaced two of the struts with approved ones. I replaced the remaining two struts rather than do the continuing inspection. That took care of the lift strut AD. Somewhat expensive, but it was relatively easy to do. Scratch one AD off the list.

However, there was the case of the lingering AD applying to the oil impellers of certain Lycoming engines. At issue was the replacement of either aluminum or sintered iron oil impellers with approved steel ones. Although the previous owner believed that the AD didn't apply to the Orphan's engine, being a very safety conscience pilot, I was not comfortable with that determination after reviewing the aircraft records and the lack of specific data saying that a physical inspection had been conducted to determine applicability of the AD. Such was my feelings about the AD before my first annual inspection "AD-P" (After Dean's Purchase).

As a retired Marine, I am a firm believer in the old adage, "When in doubt, check it out!"

Such was the situation at the beginning of what was to be a routine annual (12 month long?) inspection.

But like the famous accident theory that says an accident chain is made up of many small links, that if any one link had been broken, that break might have prevented the accident, I wanted. to build an equally strong safety chain around the Orphan to prevent an accident chain from ever starting. This is why new disk brakes and wheels were installed on the aircraft to replace the original drum brakes because I didn't like the stopping power (marginal in my opinion) of the original design. Then if you are going to install new disk brakes and wheels, it seemed only logical to install new tires and tubes. So far so good. It would cost a little more money, but a safety chain had been started and a possible accident chain link broken.

At this point, the idea was to continue using the original single handoperated brake in the aircraft rather than installing the new foot operated brake pedals purchased under a Supplemental Type Certificate authorization. This was after all a very basic Tripacer. Because of the work involved in installing the new rudder pedals and toe brakes, the new foot brakes would be installed later in the year after the weather warmed up. The goal was to complete the annual, install a new instrument panel and new communications/navigation gear and take the aircraft back to its home hangar.

Good intentions always start simple. Such was the case with the Orphan's "annual." As stated, an important part of the annual was to install a new communications-navigation package and new flight instruments. So far so good.

Then at some point the person doing the inspection and upgrades said, "You know, if we remove the windshield, it would be a lot easier to do the other work." So out comes the windshield; and another link is added to the growing maintenance chain. With the windshield removed, he decides now would be a good time to install the new foot brakes and rudder pedals. Another safety and maintenance link is added to their respective chains. At this point, the only cost is for the extra work being done since

the required items had already been purchased.

The reason for the toe brake upgrade is simple. If you have never tried to land an aircraft with one hand on the yoke, one hand on the throttle, and one hand on the hand brake, you suddenly realize that you need one more hand than is attached to your body. Maybe some well-coordinated pilots can pull that three-handed trick off, but there must be a reason most aircraft built in the last 50 years have toe brakes. Enough said. The new toe brakes were going in.

Now for those not familiar with the old Tripacer design, in this particular model, the little, single, brake handle under the instrument panel was connected by a cable to a single hydraulic brake cylinder mounted, in the Orphan, on an engine support tube.

Since the hand brake system was no longer needed, the IA (a FAA certificated Airframe and Powerplant mechanic with Inspection Authorization) removed the attached brake cylinder and its mounting hardware. Surprise. A big maintenance and cost link was uncovered at this point. He discovered that whoever had installed or worked on the brake system at some point may have damaged the engine mount tube. Why this had never been discovered during other annual inspections is not clearly understood at this point, nor does it matter. The decision to remove the engine mount and have it inspected by experts meant the engine and propeller had to come off the aircraft. This decision added a big link to the rapidly growing maintenance chain; and especially to the rapidly mounting inspection cost. When everything had been removed and the engine mount checked, the IA doing the work said the mount needed to be sent out for inspection and any required repair.

At this point, since the engine mount needed to be inspected and possibly repaired, it was a simple mental leap to decide to send the nose gear mount along with it so that everything in front of the firewall could be inspected by experts. This decision makes the dollar costs keep