Ripley98 Posted January 23, 2020 Report Posted January 23, 2020 I know this might be a topic somewhere on the forum but I’d figure I would start another. Today while flying my 76 m20f executive, I had an issue later in the flight where the gear would not retract up. It was almost as if it was not electrically connected at all. Then all of a sudden after several attempts, it retracted out of nowhere while the switch was up (about a 20 sec delay). The airspeed alarm was not functioning either when I pulled the throttle back while the switch was up (so most likely not the culprit there).Has anyone had this issue? Also a I’m a new owner so not completely familiar with the location of all switches and mechanisms that make this happen but definitely wanting to learn. Sent from my iPhone using Tapatalk Quote
carusoam Posted January 23, 2020 Report Posted January 23, 2020 feel free to update your avatar data... add your favorite location... this could be important for our guessing. Let’s see if a couple of questions gets you to the answers... Before we hit the search button... 1) Your F has a squat switch on the gear right? 2) It is wicked cold where you are right now right? 3) You know you’re rubber donuts have a best used by date printed on them right? (Actually it’s a born on date) 4) When you get a chance... check your log books to see when the landing gear rubber biscuits were changed last... 5) The rubber parts are temp sensitive, and compress over time... 6) Age and cold temps conspire to make the switch not activate properly...somehow the plane thinks it is still on the ground... and doesn’t want to raise the gear because of it... 7) Other things to consider... do you have a gear safety by-pass button? 8) You can get a button installed so you raise the gear when this happens... 9) There are lots of pics around here that detail this challenge. 10) expect cold weather to cause this challenge for every new M20F owner... 11) Modernization of the system swaps the squat switch for an air speed switch... addition of a by-pass switch is always a good idea... PP thoughts only, not a mechanic... Best regards, -a- 2 Quote
MooneyMitch Posted January 23, 2020 Report Posted January 23, 2020 My same F retract issue experiences.......associated gear motor micro switches become dirty, therefore not making contact when activated. Sometimes electrical contact cleaner on switch(s) may help. Sometimes disassembly required, sometimes replacement required. Also make sure micro switch electrical connections are secure. Hope all our information helps you. Whoops...... you’ll find the switches mounted along gear retract rods near motor by removing belly panel near gear motor. 1 Quote
Ripley98 Posted January 23, 2020 Author Report Posted January 23, 2020 12 hours ago, carusoam said: feel free to update your avatar data... add your favorite location... this could be important for our guessing. Let’s see if a couple of questions gets you to the answers... Before we hit the search button... 1) Your F has a squat switch on the gear right? 2) It is wicked cold where you are right now right? 3) You know you’re rubber donuts have a best used by date printed on them right? (Actually it’s a born on date) 4) When you get a chance... check your log books to see when the landing gear rubber biscuits were changed last... 5) The rubber parts are temp sensitive, and compress over time... 6) Age and cold temps conspire to make the switch not activate properly...somehow the plane thinks it is still on the ground... and doesn’t want to raise the gear because of it... 7) Other things to consider... do you have a gear safety by-pass button? 8) You can get a button installed so you raise the gear when this happens... 9) There are lots of pics around here that detail this challenge. 10) expect cold weather to cause this challenge for every new M20F owner... 11) Modernization of the system swaps the squat switch for an air speed switch... addition of a by-pass switch is always a good idea... PP thoughts only, not a mechanic... Best regards, -a- Yes, it does have a squat switch. I was flying in cold weather yesterday when it happened (Southeast Missouri). It did occur later in the flight. No issues when leaving the airport from my heated hangar. I will check the date on the donuts. Would the maintenance manual show where the location of all of the switches you are talking about? Also it does not have a bypass switch installed, I like the sound of it along with the airspeed switch. I also talked to Don Maxwell today and from what he was describing it sounds like the rubber doughnut issue you stated. Guess I should check those first before getting into the belly. Any ideas on the best place to get a maintenance manual? Quote
carusoam Posted January 23, 2020 Report Posted January 23, 2020 Parts and maintenance manuals are posted around here in various places... look in the download section first... When the factory is open... they make the manuals available electronically... Ebay sometimes makes some odd books appear magically... Best regards, -a- Quote
Hank Posted January 23, 2020 Report Posted January 23, 2020 33 minutes ago, Ripley98 said: Yes, it does have a squat switch. I was flying in cold weather yesterday when it happened (Southeast Missouri). It did occur later in the flight. No issues when leaving the airport from my heated hangar. I will check the date on the donuts. Would the maintenance manual show where the location of all of the switches you are talking about? Also it does not have a bypass switch installed, I like the sound of it along with the airspeed switch. I also talked to Don Maxwell today and from what he was describing it sounds like the rubber doughnut issue you stated. Guess I should check those first before getting into the belly. Any ideas on the best place to get a maintenance manual? No, you won't have this issue leaving from a heated hangar. Based on this, I'm thinking it's your landing gear pucks. My C started doing this only in the winter [unheated hangar along the Ohio River], and got worse over time. There is a date molded into each of the four pucks on each main gear, and on the three pucks on the nose gear. Be aware that they may well be upside down--I thought mine read "09/96" but when I replaced them, they read "06/69"! Pucks are generally ~$110 each, plus a couple hours labor to swap out. Cleaning the microswitch may help, with liberal spraying of Contact Cleaner, but you do need to remove a belly panel. There is a simple test in the Maintenance Manual that only requires jacking the plane and measuring the space above the metal washer on top of the gear pucks, which will tell you if your pucks are too old and permanently compressed. My stack of four new pucks was about a half inch taller than the removed stack of four old pucks, and that was after sitting on the workbench for two days for me to see. It's amazing how much nicer the plane taxies with new pucks. Landings are much smoother, too! 1 Quote
Yetti Posted January 23, 2020 Report Posted January 23, 2020 Your pucks are old. It was cold outside. Replace pucks. Quote
Ross Taylor Posted January 24, 2020 Report Posted January 24, 2020 In what year was the squat switch incorporated into the design? Asking for a friend... Quote
carusoam Posted January 24, 2020 Report Posted January 24, 2020 Ross, When the gear went electric, it got the squat switch... Somewhere in the early 70s? Best regards, -a- Quote
MooneyMitch Posted January 24, 2020 Report Posted January 24, 2020 22 minutes ago, carusoam said: Ross, When the gear went electric, it got the squat switch... Somewhere in the early 70s? Best regards, -a- And what I’ve gleaned via this thread, there are two different applications of a squat switch...... one being a mechanical switch on left main gear, and the other switch configured within the airspeed indicator circuitry. My former ‘67 F model was equipped with the airspeed squat switch. p.s. Whoops, I’m wrong. I got my squat switch information from the thread of the Mooney falling off the jacks. Quote
Yetti Posted January 24, 2020 Report Posted January 24, 2020 16 minutes ago, carusoam said: Ross, When the gear went electric, it got the squat switch... Somewhere in the early 70s? Best regards, -a- There seems to be Squat Switches over on the port landing gear and airspeed switches that sit behind the Airspeed indicator. 70s ish came with squat switch.... can't speak for the rest of the years. 1 Quote
Hank Posted January 24, 2020 Report Posted January 24, 2020 My 1970 squats on a switch attached to the left main gear. Ain't no squatting involved with a contraption attached to an instrument in the panel . . . . Mooneys went all electric in 1969. Before that, electric gear was an option. So were electric flaps. 1 Quote
Ragsf15e Posted January 24, 2020 Report Posted January 24, 2020 My 68 got electric gear at the factory when it was born and doesn’t have a squat switch. It does have the airspeed switch. Ive also had a similar problem a couple years ago in very cold weather and found my up/down switches in the belly to be gunked up and sticking. Cold made it worse. Cleaning them worked. It might be your donuts, but not necessarily, so I’d do a little more troubleshooting before spending lots o $$ for all new pucks. Generally old pucks stay compressed in the cold and thus don’t expand to (de)activate the squat switch. If you left from a heated hanger and the gear went up, it’s not sitting compressed, so that shouldn’t happen unless you landed somewhere really cold and let it sit (with weight on it for compression). When exactly did it happen in flight? 1 Quote
MooneyMitch Posted January 24, 2020 Report Posted January 24, 2020 50 minutes ago, Hank said: My 1970 squats on a switch attached to the left main gear. Ain't no squatting involved with a contraption attached to an instrument in the panel . . . . Mooneys went all electric in 1969. Before that, electric gear was an option. So were electric flaps. Terminology seems to be the culprit here.................. I stand corrected then...............my squat switch [which I've mistakenly labeled it for years and years..lol ] is an airspeed safety switch, created by Mooney. Below is an article of interest I discovered: IT'S ALL SOOOOOOOOOOOOOOO CLEAR TO ME NOW ! Gear up, rotate – No, wait! Electric gear safety system ShopTalk January 2019 In this month’s ShopTalk, we will dig into the issue of troubleshooting and repair of the electric landing gear safety system in your Mooney aircraft. You may not know this, but a new landing gear airspeed safety switch will cost you over $1,100 plus labor. First a little history. When Mooney first developed the retractable gear system in the 1950s for the new M20 series, there was no electric system available. A Johnson bar was attached to the main retraction assembly and an aluminum block was mounted on the airframe at the base of the instrument panel in the centered position. This aluminum block originally only had a hole cut into the base where the spring-loaded handle on the end of the Johnson bar would sit in when the gear was down and locked. After a few gear collapse events, Mooney added a lock pin to the aluminum block and put a slot on the spring-loaded handle to accept the lock pin once the handle was inserted into the down-lock block. The first electric gear Mooney did not show up until 1966 as an option but many manual gear Mooneys have been converted over to electric gear. This article will not go into all the different electric gear systems Mooney has used over the last 52 years. We will concentrate only on the gear safety switch. The current Mooney safety switch is different from most general aviation aircraft safety squat switches. Most GA planes have oleo struts (pneumatic air–oil hydraulic shock absorber) with a gear safety switch mounted on one of the struts. As the plane gets lighter during takeoff, the strut extends, the squat switch closes that part of the electric gear circuit, allowing the gear handle switch, when the gear handle is placed in the up position, to complete the circuit and retract the gear. The Mooney landing gear doesn’t have oleo struts but rather a rubber shock disc. Therefore, the degree of vertical travel as the weight is removed from the wheels is much less. This would be a problem for a squat switch as the adjustment would be very critical. Mooney discovered this as some airplanes in the late 1960s and early 1970s had a squat switch on the left gear. So, Mooney came up with an airspeed safety switch that is directly inline on the pitot system and vented into the static system. There were two different early style airspeed switch assemblies, but later models now use the type shown, usually mounted to the back of the airspeed indicator (see Figure 1). Early J and K airplanes did not use CPC (Circular Plastic Connector) fittings on the wires coming out of the safety switch making it possible to incorrectly connect the circuit. Later models, adopting CPC fittings helped to eliminate wiring errors, even though the connectors may appear to be identical but one side has pins inside and the other has sockets. At sufficient airspeed (approximately 60 knots), pitot pressure acting on a diaphragm enclosed in the gold colored housing (see Figure 2), closes the microswitch for the gear circuit. Now, when the gear handle is placed in the up position, the gear motor is energized for retraction. The airspeed switch is very robust and relatively simple when one looks inside the switch assembly. The gold colored housing is sealed with an O-ring. This airspeed switch assembly typically has two micro switches (see Figure 3). Mooney did make some assemblies with only one switch A cellophane-like diaphragm is located inside with a metal disc that pushes against a button that protrudes out to activate the microswitch(es). The other CPC connector and microswitch may be used to activate an in-flight timer on some clock systems. That is why when you look up under the instrument panel on an M20J or newer planes one of these CPC connectors is typically not used. If the main microswitch fails and no timer is connected, the secondary microswitch may be rewired and utilized for gear safety. After 1977, a gear bypass button was installed to allow gear retraction without airspeed, mostly utilized for retraction when the airplane is on jacks. Without the bypass, for testing, one must blow into the pitot tube to simulate the airspeed above 60 knots to activate the safety switch. Any obstruction or contaminants such as oil or water in the pitot or vent (static) will affect the operation of the diaphragm. The switches have adjustable pads where they mount to the case and using an ohmmeter and carefully pressurizing (blowing into) the pitot tube while watching the airspeed indicator, one can tell just what speed is needed to activate the switches. There are drawbacks to both squat switch and airspeed switch systems. The squat switch is out in the left wheel well and is subjected to all the dirt, water and other debris that is flung up into the wheel well. If your plane is stripped and repainted, this can also affect squat switch operation. Additionally, because the gear discs are rubber, if they don’t expand properly after takeoff, the squat switch will not close allowing the gear to retract, (think: parked outside in the cold, day after day). Of course, the airspeed safety switch has its drawbacks also. Any blockage in the pitot or static line can affect its proper operation (think: spring-time bugs looking to nest in your pitot line). Because the switch assembly is in the cabin, it is in a much friendlier environment, but when the mechanic pulls your airspeed indicator for overhaul, when re-installed, if the switch wires are misconnected, the gear won’t work. All in all, I think both systems are very reliable. So, when you are troubleshooting a landing gear problem and suspect the airspeed switch is the culprit, don’t be afraid to take it apart. At 1,100 bucks for a replacement, you can afford to spend an hour or two verifying the switch is actually FUBAR. As with this or any other ShopTalk article, if you have questions, feel free to e-mail me, shoptalk@knr-inc,com or call me at my aircraft repair shop, 307-789-6866. Until the next ShopTalk, enjoy flying your Mooney! © 2016 KNR, Inc. 1 1 Quote
Guitarmaster Posted January 24, 2020 Report Posted January 24, 2020 Yes, it does have a squat switch. I was flying in cold weather yesterday when it happened (Southeast Missouri). It did occur later in the flight. No issues when leaving the airport from my heated hangar. I will check the date on the donuts. Would the maintenance manual show where the location of all of the switches you are talking about? Also it does not have a bypass switch installed, I like the sound of it along with the airspeed switch. I also talked to Don Maxwell today and from what he was describing it sounds like the rubber doughnut issue you stated. Guess I should check those first before getting into the belly. Any ideas on the best place to get a maintenance manual? I had the same problem. Cold weather only Here's the solution....With 90% certainty, the gear pucks are the problem. You can... Replace the pucks. $$$$OrYou can adjust the squat switch in the left wheel well about 1/8" closer to the pressure plate.Sent from my Pixel 2 XL using Tapatalk Quote
Yetti Posted January 24, 2020 Report Posted January 24, 2020 (edited) Or install a gear bypass switch. @Marauder has one on his 75 F Edited January 24, 2020 by Yetti Quote
Ripley98 Posted January 24, 2020 Author Report Posted January 24, 2020 My 68 got electric gear at the factory when it was born and doesn’t have a squat switch. It does have the airspeed switch. Ive also had a similar problem a couple years ago in very cold weather and found my up/down switches in the belly to be gunked up and sticking. Cold made it worse. Cleaning them worked. It might be your donuts, but not necessarily, so I’d do a little more troubleshooting before spending lots o $$ for all new pucks. Generally old pucks stay compressed in the cold and thus don’t expand to (de)activate the squat switch. If you left from a heated hanger and the gear went up, it’s not sitting compressed, so that shouldn’t happen unless you landed somewhere really cold and let it sit (with weight on it for compression). When exactly did it happen in flight? It occurred first, approximately on a 20mile flight from my base airport after departing my second point. It was about a 2 sec delay. Then it happened again at my third point airport departure on takeoff, the leg was about 30 miles from the second to the third point. Temp was minus 3 Celsius,(this was the worst occurrence with the problem, about a 15-30sec delay before it came up).Sent from my iPhone using Tapatalk Quote
Hank Posted January 24, 2020 Report Posted January 24, 2020 2 hours ago, Ripley98 said: It occurred first, approximately on a 20mile flight from my base airport after departing my second point. It was about a 2 sec delay. Then it happened again at my third point airport departure on takeoff, the leg was about 30 miles from the second to the third point. Temp was minus 3 Celsius,(this was the worst occurrence with the problem, about a 15-30sec delay before it came up). Sounds more and more like old, hard gear pucks. The colder it is, and the longer your plane is outside, the longer the gear will take to move. Don't wait until it takes 10 minutes to finally retract . . . . The gear puck test is pretty quick, just jack up one wing and measure. Quote
Ragsf15e Posted January 24, 2020 Report Posted January 24, 2020 1 hour ago, Hank said: Sounds more and more like old, hard gear pucks. The colder it is, and the longer your plane is outside, the longer the gear will take to move. Don't wait until it takes 10 minutes to finally retract . . . . The gear puck test is pretty quick, just jack up one wing and measure. Agree that testing the pucks is worthy. Could still be sticking switches. The “gunk” in the switches seemed to get worse with cold in my case. Really it’s either pucks or switches. Cleaning the switches is real easy, especially while it’s up on jacks having the pucks tested. BTW, this problem likely won’t replicate in your A&Ps heated hanger. 1 Quote
Yetti Posted January 24, 2020 Report Posted January 24, 2020 5 hours ago, Ragsf15e said: Agree that testing the pucks is worthy. Could still be sticking switches. The “gunk” in the switches seemed to get worse with cold in my case. Really it’s either pucks or switches. Actually not switches. The switches are limit switches which means the down limit switch is not in play when you are bringing the gear up. Yes the limit switches should be serviced to a workable condition. 1 Quote
Ripley98 Posted January 24, 2020 Author Report Posted January 24, 2020 Just checked the pucks and they were from 2016. Must still be a switch. Sent from my iPhone using Tapatalk Quote
RobertGary1 Posted January 24, 2020 Report Posted January 24, 2020 On 1/23/2020 at 8:22 AM, MooneyMitch said: My same F retract issue experiences.......associated gear motor micro switches become dirty, therefore not making contact when activated. Sometimes electrical contact cleaner on switch(s) may help. Sometimes disassembly required, sometimes replacement required. Also make sure micro switch electrical connections are secure. Hope all our information helps you. Whoops...... you’ll find the switches mounted along gear retract rods near motor by removing belly panel near gear motor. And lube it and exercise both at annual as well as the unsquat switch. These need to be free to move. I use tri flow on the limit switch buttons, they are ahead of the microswitch. -Robert Quote
Yetti Posted January 25, 2020 Report Posted January 25, 2020 2 hours ago, Ripley98 said: Just checked the pucks and they were from 2016. Must still be a switch. Sent from my iPhone using Tapatalk lube gear and now you are looking for a loose wire or a bad solinoid. Put is on the jacks and sort things out. 1 Quote
Ripley98 Posted February 5, 2020 Author Report Posted February 5, 2020 Does anyone know where I can get a squat switch for this year. Sent from my iPhone using Tapatalk Quote
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