PT20J

The only way to know the condition for certain is to do a capacity test. Documentation is on the Concord website. Skip

Hey, all you airline guys -- what color are your panel lights?

The SB is indeed optional under part 91. Unless you have an included serial number and wish to change the gear speed limitation, you can ignore it. If you have a model earlier than a M20J, the SB does not apply and there is no way to change the gear speed without getting the FAA involved because the gear speed is a limitation listed in the TCDS. If you look at the TCDS for the M20J, you will note that the SB is referenced. Note also that the SB is marked FAA Approved. That's because in order to get FAA approval of the TCDS change, you can bet that Mooney sent a raft of engineering backup to the FAA. Skip

Because it's a change to an operating limitation which has to be approved by the FAA.

Well, since you are lurking about.... I took a look at the Aspen patent (attached) and thought over the calibration procedure. The calibration requires straight and level flight at two airspeeds (cruise and approach) clean, and at approach airspeed with gear and flaps down. Tolerances are pretty tight: airspeed constant to within 3 KIAS. vertical speed no more than 100 fpm, pitch change no more than one degree, roll change of no more than two degrees. (Side note: in smooth air, I was amazed at how well my 45-year-old design KAP 150 autopilot did that). The object of the clean tests appears to be to determine the lift curve and the third test is to determine the lift curve offset with gear and flaps down (the lift curve slope would be assumed to be the same in both configurations). One of the primary objectives of the algorithm appears to be to avoid the necessity for supplying the aircraft weight during normal operation. I can see why this would be beneficial as having to enter the weight would be error prone and make the system more complex to use than competing systems. The algorithm gets the gross weight stall speeds from the airspeed data entered in IAS CONFIG B. In this case, Vs is 62 KIAS and Vso is 58 KIAS from the POH. Assuming that the stall warning speed is 5 kts higher (which measurement shows to be the case), this gives stall warning speeds of 67 KIAS clean and 63 KIAS dirty at 2900 lb. Adjusting for the flight weight of 2321 lbs decreases these speeds by a factor of SQRT(2321/2900) = 0.895 or 59.9 KIAS clean and 56.4 KIAS dirty. However, during the pre-calibration flight test, I measured stall warning speeds of 56 KIAS clean and 52 KIAS dirty which are about 4 kts slower than the calculated speeds. (Aspen has you measure the stall warning speeds rather than the actual stall speed. This makes sense to me since the lift curve is highly non-linear around stall. It does introduce a source of error if the stall warning is not set correctly, but I checked mine and it is pretty close to 5 knots above stall in all configurations). It seems pretty clear that the purpose of the bias values is to correct for non-standard stall speeds. Mine are only off about 4 kts, but maybe that's enough to mess it up. I'll wait and see what Aspen comes back with. Skip WO2016164624A1.pdf

It was only an approved change to the operating limitations starting with M20J S/N 24-0378. SB M20-209 allows you to change the placard for earlier M20Js. I'm not aware that Mooney ever extended the change to the F or earlier. I think the real strain of the gear actuator is during retraction and the lower the airspeed the better. I know that the manual gear certainly takes more force to retract as the speed increases. Skip

I checked all the calibration info per the manual and it was correct. I only changed the weights because they were different for my calibration flight than the calibration after installation. There are no mods on my aircraft and it stalls at the book speeds and I checked that the stall warning is calibrated within spec. The software should be up to date as it was checked last January when the ADS-B unlock was installed. I sent Aspen tech support my test data and asked about bias values. The reply was: The “In-Flight Pre AOA Calibration Check” and bias numbers are only used for aircraft with mods that are not accounted for in the AFM, like some types of VGs and STOL kits or with conditions specified in the Limitations section of the instructions. I’ll send this over to engineering and see what they say about using the bias numbers. Maybe they can pickup on what is causing the pointer to read so high. Skip

I'm curious about other's experience with the Aspen AOA indicator. Mine, in a 1994 M20J, was installed for the previous owner. It has never indicated properly -- a normal approach ends up with the pointers near or in the cross hatch area where they are supposed to be when the stall warning sounds. I checked the configuration info and re-flew the calibration procedure yesterday and it's still about the same. I sent all the data to Aspen tech support which sent it to engineering and I'm waiting for a response. In the meantime, has anyone got one to work right, and if so did you need to add bias values or tweak anything? Skip

Not much to it as Mooney uses standard Cleveland wheels and brakes. It's a good idea to let the air out of the tube before removing the axle nut just to be safe. Be sure to torque the wheel bolts properly and don't pinch the tube. And don't get the bearing preload too tight when putting it back together. The only Mooney-specific thing I can think of is on planes with the inner gear doors you need to keep track of the washer and spacer placement to preserve the gear door alignment. Everything is covered in the Service Manual. Skip

The factory hasn't been formally revising the manuals for out of production aircraft for years. As Steve Rue explained it to me a while back, to avoid a formal revision which involves the FAA, they have been collecting changes in comments embedded in the pdf files of the last released version. If you print out a copy, be sure you update it with all the changes embedded in the electronic files. Fortunately, there aren't that many, but there are some. Skip

No apology necessary. I wasn’t aware of that procedure in the manual for your airplane, and it’s a strange one. I think if you use that technique, you will have to use the flooded start procedure to get it started.

They are backordered from Surefly so they won't ship until mid-August Skip

This is the same information that would be included in a POH/AFM for an aircraft built after 1975. Note that this is not an FAA-approved document (only the Limitations section of the POH/AFM is FAA approved). If missing, a replacement might be available from Mooney, but if they wanted to charge me much to reproduce it I would not bother because there really isn't much value to it. The original weight and balance is most certainly out of date. The only W&B that counts is the last one; no one cares about what went before except to check for possible math errors which are irrelevant once you weigh it. The equipment list might be nice, but it's probably way out of date also. The loading stations and envelope information are in the TCDS and you can reproduce the graph from that information on a piece of graph paper or just enter it in Foreflight or a smartphone app. Skip

Not sure what you mean by w&b manual. There are three items of interest. First is a weight and balance computation. If that is unavailable, one can be easily created by using the procedure in the Service and Maintenance Manual. The second is the equipment list, which I don't believe is required to be updated (and most aren't), but it can be really handy to know the particulars all the installed components when researching applicable ADs. The third item is the loading graph and stations for fuel, seats, baggage, etc. This information is generally in the POH/AFM for newer airplanes. If you don't have it, the information can be found in the TCDS. Skip

I didn't know that Mooney left the hot start procedure out of some manuals. Don't know why as it's been the same forever on all RSA fuel injected Lycomings. It might be best to review the theory. Gasoline will only combust over a fairly narrow range of fuel/air ratios. When the engine is running, the fuel injection system controls this. Starting is more difficult. Too much fuel (relative to air) and it won't start. Too little fuel and it won't start. How to get it right? For the cold start we prime which leads to a slightly rich (too much fuel) condition. As we crank, the fuel gets used up and eventually the mixture is within the ignition range and it starts. (It's really a bit more complicated than this as the fuel has to vaporize and mix with the air to form a combustible mixture which is why it's harder to start when it's really cold). Why are hot starts more challenging? When the engine shuts down, a valve in the flow divider shuts off fuel to the injectors to give a clean shut down. Still though, some fuel remains in the lines. If you restart within a few minutes, there is enough fuel in the lines to get the engine to start. If you wait longer, the fuel evaporates and you will need to prime. How long between not needing to prime and needing to prime is dependent on both time and ambient temperature. Only experience will guide you here. Why does it work to run the engine to 1000 rpm and shut down and then restart when still hot without touching anything? With a hot start, there is an unknown amount of fuel in the lines to the injectors. Immediately after the shutdown, there is some. A day later there is none. In between -- who knows? So, the biggest problem is introducing too much air. Most people open the throttle too much. Try shutting down at 1000 rpm and then close the throttle. Notice how little it is open. Skip

Just have the owner have it weighed and get a weight and balance completed. Not a big deal.

I asked Stacey Ellis what "flush windows" means and response is: Flush means it's flush with the cabin skins and held in place with only sealer whereas some older models were held in with screws around the windows I queried Don Maxwell about the same thing and his response is: Pre J Models Were glued and had screws thru the plexi glass. All later models are glued with a retainer bracket Skip

I agree with you. What I said though was that if that doesn’t work for some reason ( the usual reason is that it’s cooled long enough that it’s somewhere between a hot start and a cold start) then prime it and use the flooded start procedure. This avoids not knowing if it is not starting because there is too much fuel or not enough (and burning up the starter or running down the battery trying to figure it out). The idea is to get into a known condition (slightly flooded) and then use a procedure that works for that condition. Skip

Use the procedure in the POH. On a hot start, if it doesn’t start, prime it and use the flooded start procedure. Skip

The maintenance man at a company I once worked for showed me how to open desks and file cabinets. The way you pick a lock is to apply tension to the cylinder while raking the pins with a pick. The sloppier the lock’s made, the easier it is to get the pins to hang up at the parting line and the lock to open. Most airplane locks are so bad that you don’t even need lock picks. All you need is any key that will go in and then give it a twist while you run it in and out over the pins. About 30 seconds usually does it. My neighbor is a retired locksmith and swears by Medeco. Skip

Note the S/N cutoff for SB M20-208B. Not sure what a “flush window” is.

Looks like it’s only the balance weight that you have to change rather than the entire aileron.

I agree with Paul. From experience, the only way to tell what’s going on is to put the airplane on jacks and raise the gear and check the fit. It takes a lot of trial and error. Someone who has done this a lot can save a lot of trial and error here. Skip

It’s probably easy to change the wingtips on early Js and Ks because you can buy (assuming they are available) J/K ailerons with the balance weights made for the sculpted wingtips. Earlier models never had these wingtips from the factory and there would need to be an STC to change the ailerons and wingtips. I think it’s clear by now that these are wingtips (aesthetically pleasing but with no significant aerodynamic advantage) and NOT winglets. Winglets (aka tip sails — which I think is a more descriptive term) do offer aerodynamic improvement (forward component of aerodynamic force offsets some induced drag of the wing) but also have structural implications. Skip