Possible new AD for Piper PA28's

Tom-D said:
Who really cares what the total numbers of landings, the FAA wants to find all that have damage.
So pick a number of hours and check all that have more than that.

find the damaged ones.
Click to expand...

The point is, the ones used as personal transportation will have 5000-10000 landing cycles after 5,000 hours. The ones used as complex trainers will have 20,000+. The FAA is trying to use 100 hour inspections as a representative measure for landings. It is the best hard data they have.

Kind of like we use the Hobbs or Tach to reflect engine wear. A 2000 hour engine may be worn out or like new inside, but 2000 hours is the TBO on many Lycomings because that's the best measure they have to indicate engine wear.
 
Tom-D said:
Who really cares what the total numbers of landings, the FAA wants to find all that have damage.
So pick a number of hours and check all that have more than that.

find the damaged ones.
Click to expand...
The FAA cares because the data for the crash indicates that the unusually high landing cycles are the likely cause for the failure, not the raw tt. From other planes they have inspected only those used as trainers in high landing cycle applications appear to have problems. When they inspected planes with normal or lower estimated landing cycles despite having similar tt, they did not show signs of metal fatigue. So the FAA preliminary studies show the likely number of landing cycles is more important than tt.

Sent from my SM-G950U using Tapatalk
 
drotto said:
The FAA cares because the data for the crash indicates that the unusually high landing cycles are the likely cause for the failure, not the raw tt. From other planes they have inspected only those used as trainers in high landing cycle applications appear to have problems. When they inspected planes with normal or lower estimated landing cycles despite having similar tt, they did not show signs of metal fatigue. So the FAA preliminary studies show the likely number of landing cycles is more important than tt.

Sent from my SM-G950U using Tapatalk
Click to expand...
Problem with that is we don't log landings, we do track hours.
Where did you get the info that the FAA inspected like aircraft, with different landings?
 
Tom-D said:
Problem with that is we don't log landings, we do track hours.
Where did you get the info that the FAA inspected like aircraft, with different landings?
Click to expand...
In the initial investigation of the crash the FAA inspected similar aircraft with similar maintenance histories. Here is the report.....

https://www.aopa.org/news-and-media/all-news/2018/may/16/ntsb-finds-metal-fatigue-in-piper-wing

The examined 10 other PA28R's from a few different schools and found 1 other with similar cracks.

This article is also interesting and goes into a detailed history of the 1987 AD.

https://www.piperflyer.org/maintena...32-wing-spar-cracks-what-you-should-know.html

This is still not a common problem by any means. Both wing failures were in aircraft with 7000 plus tt, and considered high stress applications. From what I have read cracks have been found in 5 more planes (4 of these were during the 1987 inspections). With them fitting the same general criteria. That is why the FAA is continuing to try to find criteria that will affect these high stress mid to high time planes without grounding many planes that are very unlikely to have issues.

Sent from my SM-G950U using Tapatalk
 
drotto said:
In the initial investigation of the crash the FAA inspected similar aircraft with similar maintenance histories. Here is the report.....

https://www.aopa.org/news-and-media/all-news/2018/may/16/ntsb-finds-metal-fatigue-in-piper-wing

The examined 10 other PA28R's from a few different schools and found 1 other with similar cracks.

This article is also interesting and goes into a detailed history of the 1987 AD.

https://www.piperflyer.org/maintena...32-wing-spar-cracks-what-you-should-know.html

This is still not a common problem by any means. Both wing failures were in aircraft with 7000 plus tt, and considered high stress applications. From what I have read cracks have been found in 5 more planes (4 of these were during the 1987 inspections). With them fitting the same general criteria. That is why the FAA is continuing to try to find criteria that will affect these high stress mid to high time planes without grounding many planes that are very unlikely to have issues.
Click to expand...
Seems to me,,TT is the answer that will not be confused and get. all the A/C that maybe involved.
 
Tom-D said:
Seems to me,,TT is the answer that will not be confused and get. all the A/C that maybe involved.
Click to expand...
Let's just require every Piper single engine aircraft flying to have the inspection at the next required annual OR 100 hour inspection and thereafter at every annual for eternity. That would be safe.
 
Tom-D said:
Seems to me,,TT is the answer that will not be confused and get. all the A/C that maybe involved.
Click to expand...
What the FAA is trying to avoid is a repeat of the 1987 AD which was set at 5000 hrs tt. The yield from that was very low, and owners and operators were complaining the check was very expensive at $3000 (in 1987 dollars), and was a risky and invasive inspection that could damage an airworthy aircraft (which several people have pointed out here). Since they have yet to determine a best inspection procedure short of pulling the wings, The FAA is attempting to limit the number of aircraft subject to a very invasive and very expensive inspection. So this equation is an attempt to avoid the problems and criticisms with the 1987 AD, while finding the affected aircraft.
 
You must log in or register to reply here.
Back
Top