COMANCHES IN THE 21st CENTURY
NO-HOLDS-BARRED TWIN COMANCHE SHAKEDOWN
Progress Report … by Todd La Neve
Ten and a half months after dropping it off at Hagerstown Aircraft Services (HAS) in Hagerstown, Maryland (HGR), I finally got to fly my PA-30 again. I wasn't going to be taking it home, but the day had finally come for a big shakedown flight to check the new systems. We ended up logging almost four hours and had a chance to fully exercise most of the systems to find the remaining bugs. Counting on making one flight segment terminate at my home base in Clarksburg, PA later that afternoon, I had arranged a one-way flight that morning in a Piper Arrow from the local flight school. Not quite a Twin Comanche, but actually a pretty nice little plane. After flying the VOR 9 approach with a circle to land on HGR's runway 27, logging some actual instrument time along the way, I felt good about the upcoming flight.
It was a good thing I arrived early because we ran into issues right from the start. The plane wasn't quite ready to go and the test pilot, Joe, and chief avionics tech, Clarence, were going over various paperwork issues to determine the extent of functioning of the various systems. An interesting question arose about whether or not an expired database in the Garmin 530 and 430 would cause the unit to lock out any attempts to load and activate an approach. This evidently happens with King and Apollo GPS units that haven't been updated. A call to Garmin confirmed that its software allows the pilot to use the expired database, although doing so in actual instrument conditions is prohibited. While these sorts of issues were being addressed, a number of interior finishing touches were completed.
Todd's no-holds-barred Twin Comanche at HGR ready for its shakedown flight
We finally loaded up around noon, having afforded the sun time to raise temperatures to a miserably humid 90 degrees and a density altitude of 2,800 feet. In my book, it was not an ideal day for sitting in a greenhouse on top of hot black asphalt. It was time to get airborne. The takeoff roll was wonderful. Just experiencing the thrust of those engines again and the shear exhilaration of the speed was worth it if nothing else took place that day. We lifted off easily with three on board and full fuel, a reminder that these planes perform well even under adverse conditions. The climbout was uneventful and the new knurled aluminum air vents began offering a little relief from the heat as the lapse rate phenomenon made itself known.
Immediately after departure, the first thing I noticed was the presence of multiple traffic targets displayed on the Garmins and i-linc courtesy of the Skywatch. With the visibility really limited by the haze, it was nice to know where not to turn. I was instantly sold on the decision to add this system to our project. During later flight segments that day it identified lots of other traffic, including a steady stream of airliners making theirs way into Dulles as we headed south. All in all, it appeared to perform flawlessly. I also noticed a number of strikes appear as the WX-500 began interpreting electrical sources around the airport as lightning. Once cleared, these did not return and we saw no strikes at all, real or perceived, throughout the day.
Once we initially got to our intended altitude of 5,500 feet, we began working with the S-Tec 55X. The heading function worked perfectly, but we ran into some excitement while trying to maintain altitude as the unit began reverse-sensing a need for upwards trim. Instead, the pitch ran away downward until the breaker popped at which point the autopilot disengaged leaving us in an unusual attitude experiencing negative Gs as the plane pitched over heavily. With two of us on the controls, we arrested the descent and Joe quickly cranked the trim lever back up before we lost too much altitude. Joe has flown extensively as a bush pilot and has a gifted feel for any airplane I am told. He certainly knew how to handle 99R with complete aplomb. After talking through the scenario, we set up the autopilot to try to get it to do the opposite. As if on cue, it began a runaway pitch up when it should have gone down. After the trim handle had made about three rotations, we disconnected the autopilot. This time we were ready for the pitch up and didn't lose much airspeed before we were level again. It appears that the runaway may result from the unit thinking it needs a pitch adjustment, trying to do so with a reversal somewhere in the system, and continue trimming in what it incorrectly believes is the proper direction until the circuit is overloaded. As such, a change in the reversal should address the problem.
After playing around with the S-Tec a little more, we turned back toward Hagerstown, mindful of P-40, the prohibited area surrounding Camp David, and started the full ILS approach to runway 27. As we began reducing manifold pressure to slow down, the gear warning horn started sounding. We were still at about 20.5" MP so it quickly became evident the microswitches had not been reset. To keep the noise from interfering with us checking the performance of the Garmins on the approach, we kept the throttles up. It stopped the horn, but we flew the final approach segment at about 198 mph groundspeed! Fortunately, the 55X's heading function was locked rock steady on the localizer, so we only had to stay on the glideslope by hand. Since this was going to be a missed approach, we didn't worry too much about the speed, but I'm pretty sure the tower controller wondered about the poor little 172 which was thankfully on a very short final ahead of us!
After the missed, we flew off to the initial approach fix for the same VOR 9 approach I had flown earlier in the day. However, I have to admit that by that point, nearly an hour into the flight, the heat, turbulence, and abrupt maneuvering had me wishing for a little solid ground under my feet. I took over the controls from the right seat and relinquished systems control to Joe with support from Clarence in the back seat. Getting the controls in my hands not only made me feel a little better, but it renewed my sense of yearning and attachment to my plane, along with my anxiety to get it back home.
After lunch, Joe and I loaded up to fly to Shannon Airport in Fredericksburg, Virginia. The folks at Hagerstown Aircraft Services had a client there that needed some information and it offered a chance for us to see how the plane and systems would perform on a cross-country. Shannon is a 2,900 foot strip south of Washington, DC, so we had to be careful to stay outside the ADIZ since we weren't on a flight plan. It was nice to have three independent moving maps telling us exactly where we were. It was an especially nice comfort when we compared our situation to several aircraft throughout the flight that were getting stern advice from unseen watchers high above. For the most part, these were simply warnings to pilots who had strayed inside the ADIZ to immediately depart with the most expedient vectors being provided to them by military AWACS aircraft. The Garmins and i-linc are amazing units and I'm really happy with the choice to include them in the upgrade. They were a bit daunting at times and there is obviously a lot of learning ahead, but it promises to be a fun challenge. It's also nice to know that the Garmins are equally adept at allowing a pilot to step back in complexity if things start to get overwhelming by remembering they also act as basic nav/comm units with VOR heads for guidance. The best avionics advice I ever read reminded the reader that knowing how to simplify your systems by an order of magnitude may well be the most important feature to learn when stepping up. It's a lesson I'll take to heart -- if in doubt, simplify.
We tried our speed trick again approaching Shannon, but quickly decided the short runway merited a little inconvenience from the gear horn. After slowing appropriately, we dropped the gear earlier than ordinary and silenced the horn. I was a little apprehensive about the landing, this being the second shortest field I'd flown into in 99R. This was not helped by my diminished familiarity with the plane. As a result, my landing was, shall we say, less than completely graceful. But I got it down with plenty of runway to spare and without bending any of the new parts.
We finished up at Shannon and, once running smoothly, headed to the runway and blasted off northwest, right into the teeth of a nearly direct 15-17 knot headwind. In spite of the winds, we managed an average groundspeed of about 191 mph at a power setting of 23"/2500, OAT of 820 and fuel flow of 9 gph per side. On this leg we noticed the number one VM1000 tach reading was "bouncing" around and that it would periodically blank out for just a split second. After reappearing, it would stabilize for awhile and then repeat the performance. The engines were running evenly and smoothly, so it appears this is likely some sort of transducer issue. Tracey, the owner of HAS, assured us he typically sees this with the VM1000 in the OMF Symphonys that HAS assembles. However, after the first few hours, once the system has gotten fully charged and exercised, the units perform flawlessly. It was tricky to get a handle on the leaning procedures as I'm still new enough to flying that I was just finally comfortable with doing it via the old analog gauge method. It seemed a little intimidating, but I suspect practice is all it will take to get comfortable. Otherwise, the attributes of this unit were readily evident and I'm very happy to have a pair nestled in the panel.
We finally neared Clarksburg and contacted approach for clearance to fly the full VOR 3 approach with a circle to land on 21. This request was granted and we set up the Garmins for the procedure. This time we also utilized the map function of the Sandel EHSI and found that it provides a really nice accompaniment to the other units on an approach. The procedure came off nicely and we found the runway right where it was supposed to be. I was ready to try the no-flap landing technique I picked up at the recent Larry Larkin seminar since I had 7,000 feet of runway ahead. I kept my speed at 140 mph around the patch and slowed to 120 mph on final, having already put the gear down abeam the numbers. Backing off the power on very short final led to crossing the threshold around 110 mph indicated and easily settling into ground effect, touching down smoothly around 95 mph. I even managed to hold the nosewheel off for a few seconds, feeling like a real pro. This was particularly important as there was a crowd of airport regulars, including a few of the maintenance staff, awaiting my arrival. Most had become jokingly skeptical that I still had a plane and were beginning to theorize that it had been repossessed, my regular trips to Hagerstown being just a ruse! Boy did I prove them wrong. Of course, it's going to be especially sweet when she comes home to stay for good. I just hope the shop's prediction of no more than another week to debug and deliver is accurate. The critics may come back in force otherwise!
Todd La Neve, 36, resides in Clarksburg, West Virginia. He and his brother, Steve, 43, jointly own N599R, a 1966 Twin Comanche, which is based at KCKB. Todd started flying in May 2000 and currently holds a private pilot license with ASEL, AMEL, and instrument ratings. When not practicing law, he is either flying, thinking about flying, bumming around the airport watching flying, or spending time with his family trying to get them hooked on flying. So far, his three-year old daughter, Lindsey, pictured here, is his biggest convert. He's an optimist though and believes there is hope for the others.