Control of Deferred Items and History
Thread Starter
Joined: Mar 2011
Posts: 21
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From: Spain
Control of Deferred Items and History
How does your Airline control deferred items ?
In your deferred items list how do you know if the same item has been closed as fixed.
The item may have a history of being fixed and then reappears again.
The MEL Cat C items get closed but then come back again.
How long does your company keep the technical log history of maintenance defects ?
You can write up a item such a BSCU 1 Fault in the A 320 and it gets closed by one engineer Ground Test ok, the other investigates and finds the wiring problem.
Say you want to look back into the history of a deferred item in your company but the tech log book is not on the aircraft ?
Curious to policies on these questions on different airlines.
In your deferred items list how do you know if the same item has been closed as fixed.
The item may have a history of being fixed and then reappears again.
The MEL Cat C items get closed but then come back again.
How long does your company keep the technical log history of maintenance defects ?
You can write up a item such a BSCU 1 Fault in the A 320 and it gets closed by one engineer Ground Test ok, the other investigates and finds the wiring problem.
Say you want to look back into the history of a deferred item in your company but the tech log book is not on the aircraft ?
Curious to policies on these questions on different airlines.
Joined: Dec 1998
Posts: 3,038
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From: .
How long does your company keep the technical log history of maintenance defects ?
There are laid down procedures for repetative defects and what to do with them.
Joined: Aug 2008
Posts: 41
Likes: 0
From: somewhere north of south
our MELs are monitored by maintenance watch, they ensure fault finding, parts ordering ect are carried out.
A copy of the closed deferral is kept in the aircraft tech log for ten days.
Any engineer can easily access defect history through our computer maintenance system.
I guess "no fault founds" happen everywhere.
A copy of the closed deferral is kept in the aircraft tech log for ten days.
Any engineer can easily access defect history through our computer maintenance system.
I guess "no fault founds" happen everywhere.
Joined: May 2007
Posts: 257
Likes: 0
From: Castlegar
Parts, spares-shelf, parts-pool: defect history tracked?
From top slot:
Lessons from this were recorded in AAR93-04 [L1011, post-accident fire, hull loss, JFK, 30Jul92 :
AAR93-04, pg 66, Finding #16:
"... item may have a history of being fixed and then reappears again.... How long does your company keep the technical log history of maintenance defects ?..."
The specific part has a history. After a pilot observes the usual intermittent fault, Line-MX usually quickly R&R's the "faulted" component -- which later results in a bench-check of that item: perhaps "Could Not Duplicate", then the component goes back to the spares-shelf. If the stocked-item is used amongst a parts-pool, it might later be pulled out of supply, then installed on aircraft from various operators.Lessons from this were recorded in AAR93-04 [L1011, post-accident fire, hull loss, JFK, 30Jul92 :
AAR93-04, pg 66, Finding #16:
"The right AOA sensor had experienced nine previous malfunctions (eight times before being installed on N11002) and was inspected and returned to service without a determination on the reason for intermittent malfunction. The repetitive malfunctions were not detected by the TWA quality assurance trend monitoring program because the program used a calendar day, rather than flight hour, basis to detect trends.
AAR93-04, Analysis section 2.5, pg 61:"… TWA's quality assurance program to prevent a defective part from being installed on N11002 involves a subtle but critical flaw in TWA's program. Specifically, the chronic part failure trend monitoring system was established on a calendar day basis (rather than a flight hour basis) that only provided an alert to the quality assurance personnel if multiple failures occurred within a specific number of elapsed days.
"Unfortunately, the manner in which the AOA sensor was processed following each failure prevented the detection of the chronic nature of the problem. Specifically, after each malfunction the component was inspected by maintenance and subsequently cleared for service: however, the sensor was returned to supply as a spare part before being reinstalled on another airplane. Therefore, many calendar clays elapsed before the part was reinstalled on another airplane and placed in a situation in which it could fail again. Had TWA's trend monitoring system also been based on a number of hours of flight service of the part, the chronic nature of the problem would most likely have been detected."
"Unfortunately, the manner in which the AOA sensor was processed following each failure prevented the detection of the chronic nature of the problem. Specifically, after each malfunction the component was inspected by maintenance and subsequently cleared for service: however, the sensor was returned to supply as a spare part before being reinstalled on another airplane. Therefore, many calendar clays elapsed before the part was reinstalled on another airplane and placed in a situation in which it could fail again. Had TWA's trend monitoring system also been based on a number of hours of flight service of the part, the chronic nature of the problem would most likely have been detected."
