Admittedly I am probably a little to anal about the mechanics of an airplane.
The A&P says fly it and report the problems to me......well, to me, any problem with an airplane is a SERIOUS problem and some things I am told just don't sit very well with me.
We are talking about a 1977 non-turbo, straight-tailed Lance here.
1) There is a foot numbing vibration at 75% power that seems to diminish as power is reduced. My first thought was the static or dynamic balance of the prop. The prop is a Hartzell 3 blade with about 1250 hours and 13 years on it. It was replaced at the time of the engine rebuild in 2002. I didn't realize that the TBO on a prop was 2400 hours or every 6 years. It is a midwest plane so I doubt there is any corrosion and there is no sign of play on any of the blades by rudimentary checks. My decision is to have it rebuilt anyway because of the age. The hub AD does not apply as it was manufactured after that date.
2) This plane was purchased from an owner who flew it often during the last 13 years, I felt safe with that. However he had the auto-gear extension/retraction turned off (not disabled). He pulled the bulb out of the yellow indicator. We put the back in and it flashes yellow, we are OK with that. On our 4 hour flight yesterday, the RED gear extension light came on for several minutes and then went back off. This happened 3 times. I wasn't really able to tell if it was during turbulence or not, but it was alarming at 155 knot cruise speed and then on descent. After reading this forum I can assume that either one of the gear up micro switches is bad, or the pump is not holding the correct pressure to keep the gear up. We did NOT cycle the gear to see if the problem went away, it went away by itself. My first check will be to jack the plane up, raise the gear, then wiggle the gear to see if I can make the RED light come on. The second check will be to partially extend the gear, leave and come back in the morning to see if it is in the same position. I feel as though this gear problem may be the vibration we are feeling. Am I on the right track?
3) We have the same pressure guage fluctuation problem as I see in many of these forum postings. This is a fuel-injected 540. The previous owner says he never had a problem with this in 13 years until last year. He had his mechanic change the fuel pump, etc. etc. He finally resolved the problem by disconnecting the fuel pressure hose at the firewall and adding a little air to the line. Apparently that worked as the problem went away for 2 months, now it is back, since we purchased it. It doesn't appear to change with the electric pump on or off. I have seen on this forum where some people have added air to the line, some have bled the line, some have put a loop in the hose. Being pretty logical, I find most of this stuff hard to believe. Did this plane really escape this problem for 30 years and all of the sudden develop? Several senior members here have suggested a new mechanical fuel pump, I kinda have to go with that one too. Any additional ideas as I am really confused on this one? I am tempted to replace the guage, line, firewall feedthru and anything related right down to the fuel pump. I just don't trust it!
4) Strut problems. The struts on this plane are just not consistant. I know the front should be 2.25 and the mains should be 4". The mains are at 2" and 2.5" respectively. They were aired up to 4" one evening as a preflight repair, the next morning they were back down to the 2" and 2.5" and the plane wasn't moved, gassed or started. There is no red fluid leaking from either strut and I assume if the air was leaking out that the strut would be bottomed out as there is no way for it to leak just some of the air. Are the oil levels incorrect? I am about ready to service the struts as per the maint manual and just wondering if there were any thoughts.
5) This is a tough one. Keep in mind I aw used to my Cherokee and have NEVER noticed this in that plane. When we purchased the Lance I noticed that there was some warpage on the top of the sheet aluminum between the spars, similar to looking at a car with a black paint job having waves in the body panels as you look down the side. I didn't really think too much about it. I noticed yesterday as I was sitting in the back seat that every time we hit turbulence the wing panels waved, like water, each individual panel between the spars, on both wings. This concerns me as there are a couple of creases in the aluminum panels on the edge where edge of the spar contacts it. All the rivets are in place, tight and none are missing. I am just concerned about that individual movement of the panels. Obviously I understand that the whole wing should move, but individual panels? All AD's including spar corrosion have been checked and no corrosion has been found. Thoughts? The plane does have Vortex Generators installed. Anyone else notice this on the Sixes, seems like it should be more solid.
Thanks!
The A&P says fly it and report the problems to me......well, to me, any problem with an airplane is a SERIOUS problem and some things I am told just don't sit very well with me.
We are talking about a 1977 non-turbo, straight-tailed Lance here.
1) There is a foot numbing vibration at 75% power that seems to diminish as power is reduced. My first thought was the static or dynamic balance of the prop. The prop is a Hartzell 3 blade with about 1250 hours and 13 years on it. It was replaced at the time of the engine rebuild in 2002. I didn't realize that the TBO on a prop was 2400 hours or every 6 years. It is a midwest plane so I doubt there is any corrosion and there is no sign of play on any of the blades by rudimentary checks. My decision is to have it rebuilt anyway because of the age. The hub AD does not apply as it was manufactured after that date.
2) This plane was purchased from an owner who flew it often during the last 13 years, I felt safe with that. However he had the auto-gear extension/retraction turned off (not disabled). He pulled the bulb out of the yellow indicator. We put the back in and it flashes yellow, we are OK with that. On our 4 hour flight yesterday, the RED gear extension light came on for several minutes and then went back off. This happened 3 times. I wasn't really able to tell if it was during turbulence or not, but it was alarming at 155 knot cruise speed and then on descent. After reading this forum I can assume that either one of the gear up micro switches is bad, or the pump is not holding the correct pressure to keep the gear up. We did NOT cycle the gear to see if the problem went away, it went away by itself. My first check will be to jack the plane up, raise the gear, then wiggle the gear to see if I can make the RED light come on. The second check will be to partially extend the gear, leave and come back in the morning to see if it is in the same position. I feel as though this gear problem may be the vibration we are feeling. Am I on the right track?
3) We have the same pressure guage fluctuation problem as I see in many of these forum postings. This is a fuel-injected 540. The previous owner says he never had a problem with this in 13 years until last year. He had his mechanic change the fuel pump, etc. etc. He finally resolved the problem by disconnecting the fuel pressure hose at the firewall and adding a little air to the line. Apparently that worked as the problem went away for 2 months, now it is back, since we purchased it. It doesn't appear to change with the electric pump on or off. I have seen on this forum where some people have added air to the line, some have bled the line, some have put a loop in the hose. Being pretty logical, I find most of this stuff hard to believe. Did this plane really escape this problem for 30 years and all of the sudden develop? Several senior members here have suggested a new mechanical fuel pump, I kinda have to go with that one too. Any additional ideas as I am really confused on this one? I am tempted to replace the guage, line, firewall feedthru and anything related right down to the fuel pump. I just don't trust it!
4) Strut problems. The struts on this plane are just not consistant. I know the front should be 2.25 and the mains should be 4". The mains are at 2" and 2.5" respectively. They were aired up to 4" one evening as a preflight repair, the next morning they were back down to the 2" and 2.5" and the plane wasn't moved, gassed or started. There is no red fluid leaking from either strut and I assume if the air was leaking out that the strut would be bottomed out as there is no way for it to leak just some of the air. Are the oil levels incorrect? I am about ready to service the struts as per the maint manual and just wondering if there were any thoughts.
5) This is a tough one. Keep in mind I aw used to my Cherokee and have NEVER noticed this in that plane. When we purchased the Lance I noticed that there was some warpage on the top of the sheet aluminum between the spars, similar to looking at a car with a black paint job having waves in the body panels as you look down the side. I didn't really think too much about it. I noticed yesterday as I was sitting in the back seat that every time we hit turbulence the wing panels waved, like water, each individual panel between the spars, on both wings. This concerns me as there are a couple of creases in the aluminum panels on the edge where edge of the spar contacts it. All the rivets are in place, tight and none are missing. I am just concerned about that individual movement of the panels. Obviously I understand that the whole wing should move, but individual panels? All AD's including spar corrosion have been checked and no corrosion has been found. Thoughts? The plane does have Vortex Generators installed. Anyone else notice this on the Sixes, seems like it should be more solid.
Thanks!
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