Aircraft Maintenance in the civilian world???

[P3_Super_Bee]

Here's a question for the civilian maintenance guys...

I'll use the pitot tubes for my example...

It appears there doesn't need to be any type of directive from a governing body? IE, Company A Pitot Tubes appear to not function as advertised on a regular basis. Company B comes in and says ours work as advertised 100% of the time. Can Airline A say to Company B yours look great we'll take 200. Then in turn tell maintenance to start using Company B's without any type of directive? Or are Airlines on their own in these decisions?

Another question, Are all planes the same, or are they built in blocks? For example with the P-3. A flap quadrant handle on about 45 P-3's will not work on the other 500+ P-3's in the fleet and vice versa. Basiclly in this case. During production, it was found a better way to configure the quadrant. There was nothing wrong with the first one, just the second one's design allowed for it to be manufactured easier. So because there was no design flaw as far as operation of the first it was left in place.

Just some dumb questions...

[474218]

Here's a question for the civilian maintenance guys...

I'll use the pitot tubes for my example...

It appears there doesn't need to be any type of directive from a governing body? IE, Company A Pitot Tubes appear to not function as advertised on a regular basis. Company B comes in and says ours work as advertised 100% of the time. Can Airline A say to Company B yours look great we'll take 200. Then in turn tell maintenance to start using Company B's without any type of directive? Or are Airlines on their own in these decisions?

Another question, Are all planes the same, or are they built in blocks? For example with the P-3. A flap quadrant handle on about 45 P-3's will not work on the other 500+ P-3's in the fleet and vice versa. Basiclly in this case. During production, it was found a better way to configure the quadrant. There was nothing wrong with the first one, just the second one's design allowed for it to be manufactured easier. So because there was no design flaw as far as operation of the first it was left in place.

Just some dumb questions...

In response to the first part of your question:

1. The most common is a manufactures (OEM) Service Bulletin (SB). They are regulantory agency approved and purchasing the parts kit from the OEM will also get your manuals upgraded at the same time.

Example of a OEM SB would be the Airbus pitot tubes, the airlines reported problems with the pitot tubes. The supplier of the tube redesigns them and the OEM creates a SB allowing there installation.

2. The second most common would be a Supplemental Type Certificate (STC). The operator themselves can design a modification and get the regulatory agency to approve it. Example, operator's have even been known to sell the STC to other operators. Because this change was not OEM approved the airline is responsable for up dating their manuals.

Example of an operator STC. Operators have replaced the probe type angle of attack sensors, with vane type angle of attack sensors. They wrote their own procedure for installing and calibrating the new AOA sensor and got it FAA approved it.

Second part of your question:

Running changes are made on the production line. Most of the time these changes can be retro fitted on previously built aircraft by SB. However, some changes do not lend themselved to retrofitting, like your P-3 Flap handle quadrant.

[old timer]

In principle the following apply for the majority of the operators.

1- to keep the cost as low as possible without deviating from the regulatory authority requirments or manufacture recommendations
2- to comply with all mandatory SB and ADs (if applicable to the fleet type because it is mainly safety related.
3- for recommended SBs , normally the operators will conduct the feasibility study prior implementation for these type of SB to see if it will improve reliability, durability, standardization which will at the end reduces cost or improve performance

hope this is helpfull

thanks

[P3_Super_Bee]

Thanks. Very helpful.

[474218]

Thanks. Very helpful.

In 1975 I was loaned to the P-3 production line. Rigged ailerons and elevators for 6 weeks while the man who had been doing the job for 20 years recovered from an operation.

One other thing: Thank you for your service.

[P3_Super_Bee]

Thank you, and you are welcome.

[Theoddkiwi]

Our fleet is made up of aircraft all over the shop in terms of production line number. So for me when determining whether a part can be fitted to the particluar aircraft i am working i have to consult the IPC for that specific aircraft.

The line number is obviously the sequential number in which it came off the production line.

When i investigate replacing a component (our manuals are all online)i log on to the maint program select the particular aircraft i am working on by Reg number. This will then only allow me to look at the relevant manuals for that aircraft (called effectivity).

When i consult the Illustrated Parts Catalogue, as you would know has the diagrams and a list of part numbers associated with those parts.
In many cases i may have a few options of part number that can be fitted to that aircraft. As long as the part number is listed in the IPC and NOT shaded out i can legally fit the part.

However in some cases there many be conditons to fit a particular component. Common with Avionics LRU's because often there are pairs of components. eg 2 FMC, 2 Radalt, 2 VHF, 2 EEC's. So while a part maybe able to be fitted i might have to fitted as a shipset meaning the pair LRU must have the same part number, or a specific combination of prt numbers.

Engine EECs is very common, where we have FADEC 2 and FADEC 3 EECs. Interchangability of EECs is obviously a critical safety factor to consider. Even though the physically will both fit

Then we have to make sure software loads are applicable too, sometimes the LRU might be ok, but i might have to update the loaded software.

For us the IPC is gospel, if its not in the IPC or greyed out for that particular aircraft i cannot be used.

The exception is if a Service Bulletin or Letter is available that specifies any variations on what the IPC says. Airlines often consult with the manufacturer so seek clarification and authority to fit components not listed in the IPC.

Fitting a component not effective to the aircraft will, as you can imagine get you into a lot of hot water. So something i am very careful with, but you can easily be caught out when you have conflicting or confusing info. Something that does occur even in the IPC.

[P3_Super_Bee]

Our fleet is made up of aircraft all over the shop in terms of production line number. So for me when determining whether a part can be fitted to the particluar aircraft i am working i have to consult the IPC for that specific aircraft.

The line number is obviously the sequential number in which it came off the production line.

When i investigate replacing a component (our manuals are all online)i log on to the maint program select the particular aircraft i am working on by Reg number. This will then only allow me to look at the relevant manuals for that aircraft (called effectivity).

When i consult the Illustrated Parts Catalogue, as you would know has the diagrams and a list of part numbers associated with those parts.
In many cases i may have a few options of part number that can be fitted to that aircraft. As long as the part number is listed in the IPC and NOT shaded out i can legally fit the part.

However in some cases there many be conditons to fit a particular component. Common with Avionics LRU's because often there are pairs of components. eg 2 FMC, 2 Radalt, 2 VHF, 2 EEC's. So while a part maybe able to be fitted i might have to fitted as a shipset meaning the pair LRU must have the same part number, or a specific combination of prt numbers.

Engine EECs is very common, where we have FADEC 2 and FADEC 3 EECs. Interchangability of EECs is obviously a critical safety factor to consider. Even though the physically will both fit

Then we have to make sure software loads are applicable too, sometimes the LRU might be ok, but i might have to update the loaded software.

For us the IPC is gospel, if its not in the IPC or greyed out for that particular aircraft i cannot be used.

The exception is if a Service Bulletin or Letter is available that specifies any variations on what the IPC says. Airlines often consult with the manufacturer so seek clarification and authority to fit components not listed in the IPC.

Fitting a component not effective to the aircraft will, as you can imagine get you into a lot of hot water. So something i am very careful with, but you can easily be caught out when you have conflicting or confusing info. Something that does occur even in the IPC.

Thanks Kiwi...

That's pretty close to us. Your system is a little more with the times. We have what is called the Usable On Code. As our IPB(Breakdown) is kind of jacked up.. We have two series. One for the Alpha and Bravo Airframes, and one for the Charlie. Its funny though, on the structural side of the house, parts for a Charlie can be found in the A/B pub, and vice versa. But not all. When we go to get a P/N, there might be 4 different P/N's for one part. Each P/N is listed with a "Useable On Code" which then we have to bounce that code to the code listing to see if the aircraft we are working on can use the part. Very old paper system. What you expect though the plane(as a civilian airliner was devloped in the 50's)

It works that way for TD's (Technical Directive(AD in your world) A TD might not be accomplished on all P-3's only certain ones. Sometimes TD's will be issued for an aircraft and it can not be accomplished due to a prior TD. It can get crazy. Its pretty safe to say there are no two P-3s alike. Some are similar, but there are no twins out there. It can be an avionic nightmare.

[11Fan]

@ 474218 and Theoddkiwi

Textbook answers !!


Observations from an OEM IPC guy.

[P3_Super_Bee]

How do you guys release a plane for flight? Or do you?

We have what called an Acceptance Sheet or "A" Sheet. It required 3 signatures for the aircraft to be considered "Safe For Flight"..

Signature 1 is by the person that performed the preflight cards.

Signature 2 is by the person releasing the aircraft "Safe For Flight", to accomplish this the Discrepancy log for the aircraft is reviewed for the last ten flights for outstanding gripes as well as signed off gripes. Obviously the outstanding gripes you are checking to make sure nothing is outstanding that is considered a "down" gripe, as well as making sure the plane can also perform the mission it is flying. Reviewing the signed off gripes we are looking for certain inspections are performed for certain maintenance actions. This signature is normally by the maintenance controller. The Pilot signing for the aircraft can also release himself, or another pilot, but in the P-3 world this is a rare occurrence. For instance. Im on the road acting as the Airframer and Maintenance Control. The aircraft needs flight controls rigged. Because I am signing off on the rigging, I will not inturn release the aircraft for its check flight. The pilot will release himself. This for me prevents any type of conflict of intrest arising. Though there is nothing in the manual that governs Naval Avaition to prevent me from releasing the aircraft, its a personal decision. There used to be, way back but it was removed from one reason or another.

And the 3rd signature is the pilot accepting the aircraft.

[Theoddkiwi]

I was inthe RNZAF and used to maintain the A-4Ks so pretty familiar with the old Naval maintnenace manuals.

How aircraft are released for service depends on what country and what the regs say. Airlines generally develop their own procedures what have be approved by the Authority.

Our airline has 4 level of release to service all of which must be current and certified buy an approved and type rated Licenced AME.

The Maintenance Release (for us) lasts 10 days, and a Weekly inspection is completed and certified. All scheduled maintanance due must have been completed and any open Maintenance log entries are closed or deferred before the MR can be signed.

The Daily Certification is done every 48 hours, and is you basic inspection of the airframe, oil the engines and few other tasks and any open Maintenance log entries are closed or deferred before certification. Signed for by a LAME

The Preflight is done if the aircraft has been on the ground for more than 4 hours. A basic inspection, and ensure there are no open entries in the Maintenance Log. Signed for my a LAME

Open Maintenance Log entries that the Pilots or engineers raise. These are your basic defects and maintenance. They must be rectified or Deferred by a LAME with an appropirate rating for the defect. Deferred items are the MELs (Minimum Equipment List) and NAD (Non Airworthiness Defects). Item that are not in the MEL book and deemed to be and Airworthiness Defect must be repaired before flight. The Aircraft is grounded. NADs are things like the aisle carpet being worn out.

In most cases a LAME can certify for his own work with no one else involved. The exceptions are Engine Controls and Flight Controls which require an independent inspection by a LAME who has had no input into the maintenance carried out.

If and AME does a task the supervising LAME must certify for the repair over the top of the AME.

Pilots can apply MELs provided there is no maintenance action involved.

This is how my airline runs, but others will be different. Maintenance Releases on some airlines are done annually. Our used to be 30 day MRs.

I am not familiar with FAA, but have some familiarity with JAA which is similar to out system.

[P3_Super_Bee]

~SNIP~

I am not familiar with FAA, but have some familiarity with JAA which is similar to out system.

That sound pretty close to us. We do the release every flight. Along with the Preflight, we have what is called a "Daily" that is good for 72 hours unless the plane flys then from the first take off it drops in 24 hours. Which can get confusing, because if you are at the 70 hour mark and launch the plane. If the flight lasts longer that 2 hours(taking you past the original 72) it is down for another inspection when it lands(the 24 hour part only applies if there are more than 24 hours left on the original 72. But then to we have fuel samples are only good for 24 hours from the time they are taken...