redflyer
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Aircraft Maintenance And Issues Discovered

Wed Aug 15, 2012 8:23 pm

Are issues that are discovered on structural components required to be reported during maintenance checks? What happens if, say, during a D check it is discovered that there is a crack in a structural component emanating from a rivet hole. Is the crack required to be reported to the manufacturer or even the civil authorities so that other aircraft can be checked for similar problems and, if necessary, the component or drilling/manufacturing technique modified upstream and an AD issued downstream?

I would assume there is more interest in reporting these types of issues on newer models that come up for the first D Checks (e.g., A380), but what about old dogs, like a 744, that have had many D checks performed on the worldwide fleet? If a crack is found in a structural component for an existing model, and there is no obvious reason for the crack other than it emanates from a drill hole (which would indicate improper drilling or deburring), is anything else done besides repairing it and recording the repair in the aircraft's maintenance logs?
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roseflyer
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RE: Aircraft Maintenance And Issues Discovered

Wed Aug 15, 2012 9:11 pm

There are various levels of reporting that goes to the FAA/EASA/Regulatory agency and manufacturer. For simplicity, I’ll refer to US airlines operating Boeing planes, but it applies to others to.

Serious events like Air Turnbacks, Diversions, and Rejected takeoffs caused by mechanical problems have to be reported to the FAA within a certain window (I think it is 48 hours). A summary of the event and what the fix is needs to be submitted. For example if a significant crack opened up and caused a rapid decompression and diversion, then this would be reported and mitigating action which could include inspections of the fleet could be mandated in a short period of time (days to weeks). The airline, Boeing and the FAA would all work together on this because an inspection process has to come from Boeing, the mandate to do the inspection has to come from the FAA and the summary of the event comes from the airline.

Next are significant events. These are part of the Continued Operational Safety Program. Significant items like inflight engine shutdowns, loss of cabin pressure, smoke, dual hydraulic systems loss, etc need to be reported to Boeing & the FAA. This is typically done within a week of an event happening. These are analyzed by Boeing’s safety department to see if there is an inherent safety problem with the airplane design or not. If there is a problem with the design that is identified, a process to identify a root cause and a permanent fix is initiated. This is done as quickly as possible, but sometimes it can take months or years before a design fix and Service Bulletin (with or without a mandatory Airworthiness Directive attached) is issued to address the rest of the airplanes affected.

Finally are routine events. Some airlines participate in what is called the Industry Steering Committee which is responsible for scheduled maintenance. These airlines typically provide all their maintenance records to Boeing. Boeing then uses statistical tools to analyze the frequency of failures and develops the frequency of scheduled maintenance checks for it. Around 25-50% of the worldwide fleet is involved in this process.

For serious and significant events, it does not matter how old an airplane is or when it is discovered. The reporting is based on whether the event meets certain requirements that are agreed upon. For further reading, I suggest reading SPEC2000 and IP-44.
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AirframeAS
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RE: Aircraft Maintenance And Issues Discovered

Wed Aug 15, 2012 9:47 pm

Quoting redflyer (Thread starter):
What happens if, say, during a D check it is discovered that there is a crack in a structural component emanating from a rivet hole. Is the crack required to be reported to the manufacturer or even the civil authorities so that other aircraft can be checked for similar problems and, if necessary, the component or drilling/manufacturing technique modified upstream and an AD issued downstream?

First, you should know what a D check is. A "D" check is more of a thoroughly detailed structural inspection. I have done two super D's at AS, both of them were 734's (N754AS & N767AS).

When an inspector finds a discrepancy like what you described, it gets documented and placed onto a written work card. It does get repaired. Sometimes sheetmetal work is needing to be done around the affected hole and crack, which would need to be patched up to stop the crack. It really depends on the circumstances, really.

As far as the reporting goes, AFAIK, it doesn't get reported to the F.A.A. but the Boeing Rep, in this case with AS, is on site 24/7 and is notified in case something weird happens or found.

Hope that helps.
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tdscanuck
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RE: Aircraft Maintenance And Issues Discovered

Wed Aug 15, 2012 10:38 pm

Quoting redflyer (Thread starter):

Are issues that are discovered on structural components required to be reported during maintenance checks?

Like Roseflyer said, it all depends on the issues. Normal issues, like a small crack coming off a rivet hole that's within the SRM would not normally be reported. Damage beyond the allowable limits of the SRM has to be reported because you need to get repair data.

Quoting redflyer (Thread starter):
What happens if, say, during a D check it is discovered that there is a crack in a structural component emanating from a rivet hole.

If it's within limits they'd stop-drill and repair and that would be it.

Quoting redflyer (Thread starter):
Is the crack required to be reported to the manufacturer or even the civil authorities so that other aircraft can be checked for similar problems and, if necessary, the component or drilling/manufacturing technique modified upstream and an AD issued downstream?

The existance of a crack, by itself, doesn't mean anything is wrong. All modern aircraft are damage tolerant designs, so some cracking is expected. As long as it's within the repair limits and has no other effects, no further action is required.

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HAWK21M
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RE: Aircraft Maintenance And Issues Discovered

Thu Aug 16, 2012 7:15 am

Quoting AirframeAS (Reply 2):
I have done two super D's at AS

Whats a super D.
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AirframeAS
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RE: Aircraft Maintenance And Issues Discovered

Thu Aug 16, 2012 11:36 pm

Quoting HAWK21M (Reply 4):
Whats a super D.

Pretty much a regular D check plus a C1 check at the same time. That is what we called it at AS.
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HAWK21M
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RE: Aircraft Maintenance And Issues Discovered

Fri Aug 17, 2012 8:33 am

Quoting AirframeAS (Reply 5):

Pretty much a regular D check plus a C1 check at the same time. That is what we called it at AS.

Would'nt that be a Check D...covering all lower checks....Is this a term/nickname used by employees or official ie super d
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AirframeAS
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RE: Aircraft Maintenance And Issues Discovered

Sat Aug 18, 2012 8:53 pm

Quoting HAWK21M (Reply 6):

By the department.
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PurdueAv2003
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RE: Aircraft Maintenance And Issues Discovered

Tue Aug 21, 2012 5:51 am

In the US, check out 14 CFR 121.703. This has a list of all defects that need to be reported. Each airline will have their own policies and procedure about how this information is collected, but usually when a major structural defect (such as a crack in a principle structural element or fatigue critical structure) is discovered, an inspector will document the damage and repair. That information will be submitted to records and engineering for evaluation, if necessary. Records will then handle submitting the data to the FAA and engineering will interact with the OEM if a trend of similar damage is discovered. In many cases, airlines help the OEM develop and test service bulletins based upon in-service experience and repairs.
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HAWK21M
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RE: Aircraft Maintenance And Issues Discovered

Tue Aug 21, 2012 10:14 am

Regulatory & Manufacturer is provided with Information/Data on a structural defect which is not in a normally advised likely position as per AD/SB....This can provide Information to check same on similiar Airframes & more importantly; avoid a more serious hidden situation from occuring & also come up with a solution.
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