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Mooney N94MR- Paint Project


mooneyman

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Getting the full size bottle out in half an hour is pretty easy even without the extra removal panel. But putting it back in takes me more than 2x the time to leak check and mostly get the valve cable rigging perfect so it fully shuts off. The latter seems to get messed up a lot by those not attentive to details.


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On 2/15/2018 at 7:40 PM, kortopates said:

Getting the full size bottle out in half an hour is pretty easy even without the extra removal panel. But putting it back in takes me more than 2x the time to leak check and mostly get the valve cable rigging perfect so it fully shuts off. The latter seems to get messed up a lot by those not attentive to details.


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Based on experience I now leak check any time the service center gets near my bottle. The small fittings are quite vulnerable. Our dentist how lost his life going to the PPP in AC a few years ago according to the way I read the report had a loose fitting post annual, his last known recording after leaving Michigan enroute was shortly after departure near FL 250. A most often overlooked item. Many of us rely on O2 it only takes a few minutes to spray the fittings,

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15 hours ago, rbridges said:

I'm jealous. Your plane looks so clean. I know mine has a few dings, but yours looks flawless. 

My front cowling was definitely not that smooth going into the shop. They repaired some delamination of the lower cowl and installed a new heat reflective blanket. They also did some fiberglass repairs to the upper cowl to smooth the surface. I had ding on the leading edge of the horizontal stabilizer which they also repaired. They believe this surface prep is critical in the processs to obtain the best overall finish. It’s almost a restoration rather than just a paint job. 

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4 hours ago, Danb said:

Based on experience I now leak check any time the service center gets near my bottle. The small fittings are quite vulnerable. Our dentist how lost his life going to the PPP in AC a few years ago according to the way I read the report had a loose fitting post annual, his last known recording after leaving Michigan enroute was shortly after departure near FL 250. A most often overlooked item. Many of us rely on O2 it only takes a few minutes to spray the fittings,

That's a very good practice to do and doesn't take a lot of time for something so important.

Unfortunately, the accident report left important questions unanswered about whether it was the high pressure line or the low pressure line that had a loose fitting:

"An oxygen tank was located aft of the aft bulkhead. An elbow fitting that was connected to the oxygen regulator assembly, which connected an oxygen line to the tank, was found loose. The fitting could be moved in both directions by hand without resistance."

I would guess it was the low pressure line with the loose fitting, only because since it had been 2 years since servicing the tank and regulator per the report. A high pressure line leak will leak out while the system is off thus allowing ample time for the pilot to notice loosing all the air while sitting on the ground and not just going through the air faster than normal. But a low pressure leak will only leak out air when the regulator valve is opened in the cockpit (or fails to shut off). This is obviously the more insidious failure since its only leaking in the delivery line while the valve is open and the pilot is less likely to notice his O2 is draining at faster rate than normal. However, such a leak , which is limited by the regulator, is still going to take hours to drain the tank. Plus as pilots we still have two devices to protect us, the O2 tank pressure meter which shows us the remaining tank capacity as well as an O2 Pulse oximeter. One was found in the cockpit in this accident. 

Per the accident report, the pilot took off about 12:00, read back an altitude assignment clearance to FL250 at 12:16 and then was non-responsive to ATC query 23 min later  at 12:39. Its really hard to imagine a circumstance by which the pilot could have just taken off with a near full tank of O2 and seen it drain in half an hour even if it did just happen to have the high pressure line become loose at take off - which is highly unlikely and still too fast to drain a tank. More likely the tank, which had been serviced with O2 3 months prior at annual was already getting low and the pilot figured he had a enough for the 2-3 hr flight yet didn't notice the tank meter draining while in his climb to FL250. I wonder if he even got a chance to use his pulse oximeter or look at the flow meter attached to his mask before he succumbed to hypoxia.

Very sad. But it underlines the diligence pilots flying alone in the flight level must exercise in monitoring their O2 supply, O2 flow level, saturation level and be alert for any symptoms. In my personal history it has always been the awareness of the symptoms of O2 saturation dropping below the 90's that got me to look at my flow meter and realize something was wrong and fix it. The pulse oximeter has enabled me to set my flow to achieve a desired % saturation level but has never saved me to so speak. The flow meter does that easily and if that can't be fixed, the backup emergency O2 cartridges are in the back pocket.  Which luckily I have never had to use.

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That's a very good practice to do and doesn't take a lot of time for something so important. Unfortunately, the accident report left important questions unanswered about whether it was the high pressure line or the low pressure line that had a loose fitting:

"An oxygen tank was located aft of the aft bulkhead. An elbow fitting that was connected to the oxygen regulator assembly, which connected an oxygen line to the tank, was found loose. The fitting could be moved in both directions by hand without resistance."

I would guess it was the low pressure line with the loose fitting, only because since it had been 2 years since servicing the tank and regulator per the report. A high pressure line leak will leak out while the system is off thus allowing ample time for the pilot to notice loosing all the air while sitting on the ground and not just going through the air faster than normal. But a low pressure leak will only leak out air when the regulator valve is opened in the cockpit (or fails to shut off). This is obviously the more insidious failure since its only leaking in the delivery line while the valve is open and the pilot is less likely to notice his O2 is draining at faster rate than normal. However, such a leak , which is limited by the regulator, is still going to take hours to drain the tank. Plus as pilots we still have two devices to protect us, the O2 tank pressure meter which shows us the remaining tank capacity as well as an O2 Pulse oximeter. One was found in the cockpit in this accident. 

Per the accident report, the pilot took off about 12:00, read back an altitude assignment clearance to FL250 at 12:16 and then was non-responsive to ATC query 23 min later  at 12:39. Its really hard to imagine a circumstance by which the pilot could have just taken off with a near full tank of O2 and seen it drain in half an hour even if it did just happen to have the high pressure line become loose at take off - which is highly unlikely and still too fast to drain a tank. More likely the tank, which had been serviced with O2 3 months prior at annual was already getting low and the pilot figured he had a enough for the 2-3 hr flight yet didn't notice the tank meter draining while in his climb to FL250. I wonder if he even got a chance to use his pulse oximeter or look at the flow meter attached to his mask before he succumbed to hypoxia.

Very sad. But it underlines the diligence pilots flying alone in the flight level must exercise in monitoring their O2 supply, O2 flow level, saturation level and be alert for any symptoms. In my personal history it has always been the awareness of the symptoms of O2 saturation dropping below the 90's that got me to look at my flow meter and realize something was wrong and fix it. The pulse oximeter has enabled me to set my flow to achieve a desired % saturation level but has never saved me to so speak. The flow meter does that easily and if that can't be fixed, the backup emergency O2 cartridges are in the back pocket.  Which luckily I have never had to use.

 

I totally agree. When I had my 261 conversion I generally flew her in the low to mid Fl20s. I always had a secondary oxygen bottle hooked up with attached masks strapped to the passenger seatback. I had the red/green ball flowneters in all the oxygen lines, and I religiously checked to to see that oxygen was flowing about every 10 minutes. In retrospect that was not often enough. On a flight across the country with a friend who was also a CFII /ATP, we decided to take turns taking off our masks at Fl270. I didn’t last very long - about 2 minutes before breaking into laughter and then becoming totally incoherent. I put the mask back on (these were the really high quality expensive masks with built lt in microphones), and took a good 5 minutes before I felt normal (but probably wasn’t). We repeated the test with my friend who simply dozed off, and his recovery time was a bit better than mine after we got his mask back on. Thereafter I tried to fly no higher than FL230, and mostly less than FL210. Now with my J I use oxygen above 9500’ as I feel sharper in my thinking than without oxygen. If I am on a long flight in less than ideal conditions, I’ll use oxygen at 8,000-8500’. I can feel my age (82) being a factor now, but I have no trouble breathing in non-Flying situation. Hypoxia can sneak up on you. (As can CO).

 

 

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1 hour ago, Bennett said:

I totally agree. When I had my 261 conversion I generally flew her in the low to mid Fl20s. I always had a secondary oxygen bottle hooked up with attached masks strapped to the passenger seatback. I had the red/green ball flowneters in all the oxygen lines, and I religiously checked to to see that oxygen was flowing about every 10 minutes. In retrospect that was not often enough. On a flight across the country with a friend who was also a CFII /ATP, we decided to take turns taking off our masks at Fl270. I didn’t last very long - about 2 minutes before breaking into laughter and then becoming totally incoherent. I put the mask back on (these were the really high quality expensive masks with built lt in microphones), and took a good 5 minutes before I felt normal (but probably wasn’t). We repeated the test with my friend who simply dozed off, and his recovery time was a bit better than mine after we got his mask back on. Thereafter I tried to fly no higher than FL230, and mostly less than FL210. Now with my J I use oxygen above 9500’ as I feel sharper in my thinking than without oxygen. If I am on a long flight in less than ideal conditions, I’ll use oxygen at 8,000-8500’. I can feel my age (82) being a factor now, but I have no trouble breathing in non-Flying situation. Hypoxia can sneak up on you. (As can CO).

 

 

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A side story.

Last week I was in Boulder, CO since I gave a lecture at the university.

Anyway I took Uber back to the airport.  I was chatting with the driver, who came from Nepal.  We started talking about Mt Everest.  He said he climbed Everest 4 times!  Once without Oxygen...there are only very few people in the world who have done that.  He was a Sherpa guide, and he said his name was Sherpa, as was his whole family.  He was born and lived in a village at 17,000ft I think it converted to.  I guess Boulder, CO is like low altitude for him.  He is 40 and he said he spends about half a year in US now and half he goes back and guides on the Mt.  I told him where he lived, and he said, oh yea, he has another Sherpa friend who lives near me, in Quebec.  So next time you take an Uber ride....

Think about it - climbing to 29,000ft without Oxygen?!!!  That's harder than sitting there without Oxygen since you are exerting strenuously.  I climbed a few "14er's" when I used to live in CO.  I tell you what, even though I was in top shape at the time, I really really noticed it after 12000 as every foot after that became pretty hard.

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3 hours ago, Hyett6420 said:

I was in. austria recently and my brother took me to the top of the Hex glacier, approx 11,000 we climbed up and down some steps to the viewing platform.  Oh BOY wer my legs comllaining about lack of oxygn, but then i live at sea level so it is interesting how your body acclimatises if you live in a place long enough.   

You can acclimate to 5,000 ft.  You can acclimate to 7,000.  And then climb better to 12 or 14.  But you need to be born and raised at 17 if you want to climb in the 20's,  And even so, only very few people have successfully climbed Everest, 29,000 without oxygen.

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On 2/14/2018 at 6:26 PM, dlthig said:

Will it look like anyone else's airplane? Yep, I went there.

As will I.  As far as I'm concerned I see 10 other toyota trucks that look just like mine every day (if not more).  I don't care if mine is close to someone else's ( @jetdriven) that lives across the country. Hopefully they won't care either!

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1 hour ago, Hyett6420 said:

You ever seen that sad picture of Mr Green Boots?  A sherpa who died on the mountain and is frozen up there, curled up as though asleep.  Very sad.

I have seen that picture.  I didn't know he was a Sherpa. 

One thing I learned from my Uber driver, is that he uses Sherpa as his family name.

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