This topic has 8 replies, 5 voices, and was last updated 1 year, 11 months ago by Tom Thibodeau.
June 9, 2021 at 5:15 pm #2266Ray FerrellParticipant
I recently have a gear failure on my Meyers. I was flying the plane to a maintenance shop to have a low strut filled. When retracting the gear, the right strut (the low one) did not extend. Because of this, as the gear went up, the tire was able to pass by the bail tube which closes the gear door. Of course I did not know this at the time. After a quick 5 min flight to my destination, when I extended the gear the right gear transit light remained on and no green light. After an over flight of the airport and confirmation that the right gear was not fully extended I left the pattern and attempted to fix the problem. I cycled the gear a number of times, no joy. Then I tried the wobble pump, no joy. Lastly I used the pull cables and G-maneuvers, trying to slam the gear in place, still no joy.
After landing with 2 of 3 wheels down, we discovered the issue.
Moral of the story, if you have a flat gear strut, do not retract the gear. Have it fixed 1st.
I’m wondering of anyone in the group was familiar with this potential problem. It would have been great, had I know this before that flight.:-) It will be a part of any flight reviews I might do in the future.June 10, 2021 at 3:48 pm #2268Dean SiracusaKeymaster
Very sorry to hear about that.
There are tons of things I’ve learned over the years, from the late Keith Diver and other owners, that aren’t actually in the manual, or the maintenance manual. Not operating on flat struts is one of those items.
Once you learn how the gear works (and the importance of properly inflated struts to grab the inner gear door bail, among other things) you understand better about proper operation and issues that will pop up.
In addition to the revised maintenance manual, we’ve also created a relatively small informational PDF that includes things like inspection items, parts sources and helpful people (CFIs, A&Ps, insurance brokers, etc…). We’ve also created revised checklists for various phases of operation from pre-flight to shut-down. Perhaps a new document of all the things we’ve learned which aren’t in any documents might be helpful.
I’ve been trying to add these newly revised documents to the website but I’m having some issues doing that. In the meantime, if anyone wants these documents, please let me know and I’ll share them with you directly.June 10, 2021 at 6:52 pm #2271Ed PulliamParticipant
Dean- I go in for annual end of this month. I printed the updated MM but if you have any additional pdf’s that are not in the MM< I would love to have them.
Ed P.June 21, 2021 at 2:14 am #2279
So sorry to hear about your gear extension issues with 489C. As you are aware (but others may not be), your aircraft has a different gear indicating system than other M200s. 489C has a transit lights, where stock aircraft have UP (red) and DOWN (green) lights.
The Gear system of the M200 is quite simple: an engine driven hydraulic pump with a backup hand pump, and Uplock release cables attached to the gear handle, with backup Uplock release cables that may be manually pulled if the others fail.
Here are a few thoughts to help walk through an analysis of a landing gear anomaly:
If there is hydraulic pressure indicated on the pressure gage, then pumping the hand pump won’t provide any benefit as the engine driven pump will provide more pressure than the pilot can achieve with the hand pump (especially while flying). If an Uplock cable attached to the gear handle breaks (or malfunctions), then raising the gear handle (assuming hydraulic pressure is indicated) to get the weight of the gear off the Uplock, pulling the Uplock manual cables and lowering the gear (with the manual cables held in the fully pulled position), should allow the gear to drop. Air loads will not hold the mains Up (even without hydraulic pressure), but may slow the nose from dropping. A quick wing rock will lock the mains and a quick pull up should extend the nose.
If there is zero hydraulic pressure indicated on the gage when the gear handle is lifted to energize the hydraulic system, one of 3 issues may be at play; (1) bad gage, (2) the engine driven hydraulic pump has failed, (3) there is a leak in the hydraulic system and the fluid has bled out (100 psi when in bypass will bleed the system empty quickly). You can verify a leak vs engine driven pump failure by hand pumping; no pressure = no fluid, pressure = pump failure. If no pressure (seen on the gage or felt while pumping) is gained when hand pumping, then there is probably no fluid in the system. Good news is that lowering the gear handle will release the Uplocks and allow the landing gear to fall into the DOWN position. If pressure is gained by pumping, then pump the hand pump to pressurize the system. If time permits, you may pump the hand pump with the gear handle in the UP position to raise the gear off of the Uplocks prior to moving to the DOWN position, but it shouldn’t be required if the Uplock rollers are properly lubricated. Hydraulic pressure will bleed down quickly if using the hand pump, so use of flaps will require occasional pumping to keep them down (if fluid is available and pressure can be built up). Easiest to accomplish a no flap landing to a paved runway. Be cognizant that without hydraulic pressure, small bumps may cause the gear to lose over center and collapse. Be gentle and minimize gear side loads with hydraulic emergencies.
Ray, I’m curious as to what caused the main gear to get stuck in the UP position… Did a gear door cable catch on the scissor link, or did the tire catch on the sheet metal with the retracted strut?
An easy way to get some air in a collapsed start is to jack up the aircraft and add air to the strut using the strut pump (if Nitrogen isn’t readily available). By jacking the aircraft you are not trying to lift the plane’s weight while charging the strut. It won’t get you to the 700+ psi required, but it should get it off the fully bottomed position. Final pressure will be determined by length of strut extension desired. New seals will be required if it bled down, but your mechanic should be able to rebuild the strut as it is straight forward. Also, you may want to replace the bushings while the strut is off the plane.
Practicing gear emergencies during annual maintenance landing gear swings while the aircraft is on jacks is a good opportunity to witness gear transits and learn hand pumping techniques. You may need to “backhand” the pump lever to keep from scraping your knuckles on the circuit breakers. Been there, done that, have the scars…
VR, TomJune 21, 2021 at 2:32 am #2280
One additional tidbit…
A broken gear handle Uplock cable will be apparent because without the Uplock released, the gear UP red light will stay illuminated. Basically one red, two green would indicate the Uplock did not release on the gear indicating red. Instead of trying to find which cable to pull, raise the gear by putting the gear handle in the UP position, then pull all three cables with your left hand and use your right hand to lower the gear handle to the DOWN position. Momentarily releasing the yoke will be required, so don’t do this near the ground, but while maneuvering at a safe distance from the traffic pattern at about 100mph. If you try to pull the three backup Uplock cables with the gear handle in the DOWN position, you are trying to release the Uplock with 1000psi hydraulic pressure pushing against the Uplock hook and roller. You may end up breaking your backup cable in this scenario. Without pressure on the system (hydraulic leak), the Uplock should release easily.
VR, TomJune 23, 2021 at 12:07 am #2283Dean SiracusaKeymaster
Ray’s right strut was flat and it took off with it in that condition. It apparently didn’t catch the bail and just went past it. When the gear came down the bail got in its way.
Oh, and my new Meyers 200, N2980T (Tom Wathen’s old plane) has the same gear light system as N489C and I honestly prefer the original way they’re set up as I think there are fewer failure modes where you may not get honest information about the status of the gear. At some point in the future I’d like to return mine back to original.June 23, 2021 at 2:05 pm #2284Ray FerrellParticipant
Thanks for your valuable input and info. Dean is correct, I had a low strut and was flying from FD51 to KMTH to have it serviced (A short ~ 5 min. flight). If I had the wisdom of other, more seasoned Meyers owners, I would have made the flight with the gear down. Lesson learned, all be it an expensive one.
The good news is the damage was minimal so, N489C will fly again!
There is video of the landing, if someone can tell me how to post it.
June 24, 2021 at 3:36 am #2287Mark JensenParticipant
- This reply was modified 1 year, 11 months ago by Ray Ferrell.
- This reply was modified 1 year, 11 months ago by Ray Ferrell.
Sorry to hear about your gear problem. My partner and I had a nose gear up landing which I also attributed to a problem with the strut. We bought the aircraft after an estate settlement and then had it down for about a year replacing the interior and glass. Because it sat for (?) years, it was difficult to service the strut to the proper extension. After flying for about five months, we raised the gear after take off and did not get a nose gear up indication. My partner recycled the gear and on the second try the nose gear indicated up. I think that the nose gear didn’t extend properly after take off and on the second try, it forced it’s way past the uplock. We then couldn’t get the uplock to release. I learned two things. 1. resist the temptation to recycle the gear if it indicates down. 2. If there is a problem with strut servicing or the airplane has been down for a while, have the struts evaluated carefully and over hauled if necessary.
Mark JensenJune 25, 2021 at 11:20 am #2288
So very happy to hear the damage was minimal given your scenario. Thank you for the additional information. I’m guessing the strut extended slightly once the gear was in the well to force the tire against the bail and cause it to bind. A very unusual situation to be certain.
You did an excellent 2 wheel landing and had a great outcome. Well done!
You must be logged in to reply to this topic.