PT20J

Risk management involves a number of steps. First is identifying the risks. Second is assessing the risks which is where the risk matrix (likelihood vs. severity) fits. The matrix is a tool to guide you to identify which risks are significant enough to require a risk management plan. Traditionally, risk management plan strategies fall into four categories: Avoid, Mitigate, Transfer, Accept. Examples due to a risk of icing might be: Avoid - cancel the flight. Mitigate - delay, or choose a different route below the freezing level, or use a different airplane with FIKI capability. Transfer - take an airline flight. Accept - mission is critical, press on. Skip

I think you are probably right. I have never witnessed this personally, but it does seem possible given the way the RSA fuel injection system functions. The mixture control is at the servo and there is a couple of feet of hose between the servo and the flow divider and another foot or so of line to each injector. The engine would run on for quite some time after moving the mixture control to ICO if it had access to all the fuel in those lines. To prevent this, a spring loaded valve in the flow divider cuts off fuel to the injectors when regulated pressure drops after selecting ICO. There is still residual fuel in the lines to the injectors, and I guess it could eventually drain into the intake manifold through the intake tubes and then out the sniffle drain. Skip

Yep, Don. Found it had worn half way through a one inch diameter aluminum oil supply line on the museum B-25. Hard to believe, but nylon is tough stuff. Now the one I can’t quite figure out is the claim I’ve seen more than once here (it’s also in Don Maxwell’s external tubing article on his website) that gas will drip from the sniffle after a normal shutdown. If you shut down by pulling the mixture to ICO, where does enough gas come from to collect in the bottom of the intake manifold? Skip

An IO-360 should idle well at full rich at sea level if idle mixture is set correctly. Ground leaning increases combustion temps to aid lead scavenging and reduce plug fouling. If the roughness is typical Lycoming morning sickness caused by exhaust valve sticking it should only happen after a cold start. When the engine is warm, the valve will usually free up. There are backfires and afterfires - both can make a pop. Backfires are due to too lean a mixture which burns slowly so there is still fuel burning when an intake valve opens causing ignition of the mixture in the intake manifold. This can be caused by an induction air leak. Less common afterfires occur with a rich mixture that allows unburned fuel to accumulate in the exhaust and is ignited when an exhaust valve opens. This is what happens if you shut off the ignition at cruise power for a few seconds and turn it back on (don’t do that - the overpressure can damage the exhaust components). Skip

Not to be nit picky, but... The "internal resistance" of a battery is the series resistance. But you are correct in that all batteries have a self discharge rate -- some chemistries hold a charge longer than others. Skip

Not an FAA defined V-speed. Most efficient (by one measure) climb speed Vz = 1.32 x Vy. IntroducingVz.pdf

If I understand correctly, the radios came on while you were cranking. If the battery were weak and/or the starter drawing too much current, the bus voltage might drop enough during cranking to cause the the avionics bus relay to drop out and power up the avionics bus. As described, the fail safe design is that the relay must be energized to depower the avionics bus. Skip

Altitude hold works by "capturing" the static pressure at the engagement altitude and then adjusting altitude to maintain this pressure. To get a slow, continuous climb caused by a static pressure problem would require a small, constant offset from the "captured" pressure. This is pretty unlikely. I suppose that there might be a failure mode of the pressure transducer that would produce a constant offset voltage, but that wouldn't explain the trim. The description of the trim indication is exactly what would happen if you were to pull on the yoke while the autopilot was engaged. The pitch servo tries to push the nose down, but can't because you are holding pressure on the yoke and the autopilot tries to relieve the pitch servo pressure by commanding down trim. Since the airplane presumably has no non-autopilot control issues such as binding, the failure must be something within the autopilot that mimics this condition. I would begin troubleshooting by checking all vertical modes to determine if anything works correctly. I would check the pitch servo for bridle tension and clutch slipping. If all that doesn't find a problem then it might be the autopilot itself. Skip

According to Wikipedia, that's the callsign for Presidential Aviation. https://www.presidential-aviation.com/ Skip

I think we are getting overly precise about something that's not that accurate. Ten or twenty RPM is less than a 1% variation -- probably pretty good for a hydromechanical control system. If there is a tolerance, it would probably be in the governor overhaul manual. When I had my prop resealed and governor overhauled, the combination ran up to redline in flight with no adjustments on the newly rebuilt Lycoming IO-360-A3B6. Here is what McCauley has to say about it:

OK, so there has to be a switch somewhere to select the autopilot NAV input between the KX 155 or the GNX 375. It should also switch the ILS Energize input to the KC 191.

It's been a few years since I flew a 3308. When you select the Nav source on the 3308, does it also control which source feeds the autopilot? If so, there may be a problem with the connection between the HSI and the autopilot. I assume you had the GNX 375 installed recently -- did the GS ever work correctly on both ILS and GPS after installation? It's a little tricky since you have separate units for ILS and GPS and the Sandel in the mix and it might be an issue with the installation. I'd take it back to the shop that installed the 375 and have them troubleshoot it.

The ILS Energize signal tells the autopilot to enable the glideslope when in APR mode, so it could be a cause of the problem also. Regardless of whether it's the ILS Energize or the GS signal, it is most likely a problem of the signal getting to the autopilot. Although it doesn't seem to fit this case, there is a possible installation goof when changing a GNS 430 to a GNS 430W. On the 430, the ILS Energize output is connected to the KC 191 ILS Energize input. On the 430W, the ILS/GPS Approach output should be connected to the ILS Energize input on the autopilot or the glideslope will only work on ILS approaches and not GPS approaches. Skip

Beating a dead horse, but last week I requested a SDS from Phillips and I finally got it. Phillips Victory AW oil uses triphenyl phosphate. Skip 831793.pdf

OCV only measures “percent charged.” The capacity test measures the time it takes to reach a terminal voltage with a rated load and thus measures the capacity of the battery. During this test, the terminal voltage will decrease with time following an unspecified curve. If you were to take a known good battery and put a known load on it for a given time and measure the voltage at the end of the test, you would have a benchmark to do a quick and dirty test against another battery of the same model that is of unknown condition because you could reasonably assume both batteries would follow the same discharge curve. It’s not as definitive as a capacity test, but it’s not an unreasonable quick check. I’d run it for more than a minute though - maybe 10-15, depending on the load, to get enough drop to be representative since the voltage versus charge curve for a lead-acid battery is not linear and tends to be “flat” near the fully charged end. Skip

If MET works, the trim servo is working. If it holds pitch when not in ALT, or altitude when in ALT, the the pitch servo is working. The servos, logic and lights get tested during self test. Not getting GS light probably means that it’s not getting a glideslope signal. Since you mentioned LPV, you must have a WAAS navigator. Good place to start is to check the output of that. If you have an Aspen, the signal will come from the ACU. Skip

Went to the APS seminar in Ada years ago from San Jose in a rented Arrow with dual KX 155s, a transponder, a broken DME, no autopilot, and paper charts. When I arrived, the place was overrun with Cirrus pilots comparing their weather subscriptions, WAAS GPSs and glass panels. They couldn’t believe a little basic airmanship made it possible to find Oklahoma, let alone the little town of Ada, with such basic equipment. I like my Aspen, GNS 430W, GTX 345 linked to my iPad. But, it’s good to remember that I don’t need all that. But then, I had an instructor that made me do intersection holds with a single NAV. Skip

Begin with throttle set for 1000 rpm, mixture ICO and crank. If it doesn’t fire in a couple of revolutions, slowly richen mixture until it fires, the go to full rich and adjust rpm with throttle. Skip

Observation: some owners complain that their mechanic is too picky (expensive) others feel their mechanic isn’t thorough enough. The FAA gives mechanics a lot of leeway to use good judgement to determine what is airworthy and it’s not all black and white, so find a mechanic that has standards that match yours an you’ll both be happier. Skip

Certification standard for non-spin-approved airplanes was recover from a one turn spin within one additional turn. A spin is not generally fully developed until after about two turns, so it may or may not recover easily from a multi-turn spin. Bob Hoover recounted in Forever Flying how he used to spin the Shrike until one time it went flat on him and he almost didn’t get out of it. So, even if you do it successfully once or twice, that doesn’t necessarily prove anything. Skip

You’re paying a lot and you should get what you asked for. While your sketch is hand done on the wrong outline drawing, it’s still pretty obvious that you were asking for smooth curves. If it were me, I wouldn’t pay any outstanding charges until we renegotiated. I’d try to get them to strip and repaint it. Probably would end up settling for a deep discount. I don’t see any way this is your fault. Skip

GAMA publishes statistics yearly. Lots of interesting stuff in there. FAA defines “active” as having current medical certificate. https://gama.aero/facts-and-statistics/statistical-databook-and-industry-outlook/ Skip

Properly rigged, the J (should be the same with others, but I haven't tried it) will fly straight and level hands off trimmed to 90 KIAS for several seconds. Eventually it will roll off to one side. As it does the nose will drop, the airspeed will increase and the bank will steepen. At some point though, the longitudinal stability takes over and the nose will rise and the airspeed will drop. It makes about 2-1/2 cycles of this phugoid and then settles into a constant airspeed, constant descent rate, approximately 45-deg bank descending spiral. Skip

Certainly agree with that. The Mooney flap mechanism is not very robust. I probably should have been more clear: exceeding the flap and/or gear speeds once in a great while doesn't seem to hurt anything, but those speeds aren't arbitrary and continued abuse will eventually take its toll.

Byron, curious what your scheme design and paint mask cost.