Narrative:

I was called by maintenance control for air carrier X to inspect a main landing gear (medium large transport) tire with a piece of metal in it. I measured the depth at just over 3/4' of an inch deep; 'out of limits'' the aircraft maintenance manual (amm) reference only allows damage [to a tire] to go through one ply. Air carrier X said they were going to send their own mechanics with a tire. I ask how they wanted me to short-sign the logbook. Maintenance control said not to put anything in the logbook. I asked several times. It is not normal procedure to 'not' sign for the work you did and you are supposed to document any maintenance you do. I was suspicious; because they could send someone to just sign-off the tire and no-one would know that it was initially determined to be out of limits. I went ahead and documented my work in a short sign-off without the direction of maintenance control. That is where you document the work you did and sign your name and airframe and powerplant (a/P) number within the corrective action; but do not sign the 'return to service' block. I was called back several hours later by maintenance control. They said I did not sign-off the work correctly. This seemed strange because the mechanic that would change the tire would document the logbook immediately following my entry and he would sign the 'return to service'. I went back to the aircraft and maintenance control said I had to sign-off the logbook. I signed the 'return to service' and wrote a new discrepancy on item-2 of the same log page; repeating the original write-up. The tire change was to be completed on this item. It was at this time that I found out that the air carrier mechanic did not bring a tire and was going to sign-off the tire as 'in limits'. She was doing what maintenance control was telling her. I told her not to sign it off; do not let maintenance control talk you into doing something that is not legal. There were two air carrier mechanics that came. Neither one had measured the damage or had the amm reference showing allowable damage. Anyway I told them and maintenance control I was going to call the FAA three days later. My intention was to get the air carrier contract manager on a conference call with their quality control and the FAA and discuss it to see what can be done about maintenance control having some oversight; as this happens too often. Three days later; I was contacted by the air carrier contract manager and we discussed it.the one thing on my count that may have been done wrong is the way the short sign-off was done. Since I asked maintenance control how to do it and they said; 'do not put anything in the logbook'; I may have done it different than what their general maintenance (or procedures) manual (gmm) says to. Also; I did not include 'emb-145' before the amm reference which may be mandatory per their gmm. Also; I used the standard six digit amm reference and their gmm may require a longer amm reference. I do not have access to their gmm and as always; rely on their maintenance control to guide through their proper procedures. Even though I believe that short signing the logbook was the correct thing to do; I did so without the permission of maintenance control. I was told that the aircraft was signed-off for revenue flight. This is very surprising to me since I made sure the air carrier mechanics; maintenance control and the captain knew I was going to discuss this with the FAA later and I expressed that the puncture in the tire was very deep and possible almost through the tire. Per our conversation; the reference I used was the correct one; amm 32-49-01. I was called back later to sign-off item one; and then I made a second log entry saying 'reference log page XXXX; item-1; left medium large transport inboard tire has a piece of metal stuck in it'. Air carrier mechanic was to change the tire on this block. Maintenance control said they had a reference for the depth measurements of the tire cord. I told them I don't believe anymanual will reference the depth of the cords; but if they have them; fax them to me. They refaxed over page 607 diagram of the tire which shows the cord but does not reference the depth of each cord. The damage; being a puncture; does not have access to view the cords. The amm does not specifically give limits for punctures; so you have to use the cut limits which state damage is only allowed to go through one ply. The first ply is usually approx 1/32' of an inch below the groove. The damage was just over 3/4' of an inch deep. The tire had good tread; so the damage was just over 1/2 inch below the groove. Yes; there is no way to verify if it went through one ply; unless you had the measurements for the plies; but good judgment says it went through many if not most of the plies; maybe almost through the whole tire. Maintenance control was aware of the measurements and the 'out of limits' condition. When I was called back over to sign-off the logbook; I realized that they did not change the tire. I told the air carrier mechanics not to sign it off. They had not even measured the damage. They were going off of what maintenance control was telling them. They did not even have the maintenance manual (M/M) reference with them. I had to go back to the [maintenance] shop and dig the amm out of the trash for them. I went over the limits with them. The air carrier mechanic called maintenance control; and the maintenance control (I take it he was the maintenance director) wanted to talk to me. I told him it was so far out of limits that there is no way he should be trying to throw these guys under the bus to sign it off. Unfortunately maintenance control did not have any documentation to show what the depth measurements were for each ply; which would have been the only way to definitively determined how many plies the damage went through.

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Original NASA ASRS Text

Title: A Contract Maintenance Technician describes his efforts to have a Main Landing Gear (MLG) tire replaced on a EMB-145 aircraft and not just signed-off as 'within limits' by one of the Air Carrier's mechanics. The MLG tire had sustained a deep puncture by metal debris that had cut through multiple plies.

Narrative: I was called by Maintenance Control for Air Carrier X to inspect a Main Landing Gear (MLG) tire with a piece of metal in it. I measured the depth at just over 3/4' of an inch deep; 'Out of Limits'' The Aircraft Maintenance Manual (AMM) reference only allows damage [to a tire] to go through one ply. Air Carrier X said they were going to send their own mechanics with a tire. I ask how they wanted me to short-sign the logbook. Maintenance Control said not to put anything in the logbook. I asked several times. It is not normal procedure to 'not' sign for the work you did and you are supposed to document any maintenance you do. I was suspicious; because they could send someone to just sign-off the tire and no-one would know that it was initially determined to be out of limits. I went ahead and documented my work in a short sign-off without the direction of Maintenance Control. That is where you document the work you did and sign your name and Airframe and Powerplant (A/P) number within the Corrective Action; but do not sign the 'Return to Service' block. I was called back several hours later by Maintenance Control. They said I did not sign-off the work correctly. This seemed strange because the Mechanic that would change the tire would document the logbook immediately following my entry and he would sign the 'Return to Service'. I went back to the aircraft and Maintenance Control said I had to sign-off the logbook. I signed the 'Return to Service' and wrote a new discrepancy on Item-2 of the same log page; repeating the original write-up. The tire change was to be completed on this item. It was at this time that I found out that the Air Carrier Mechanic did not bring a tire and was going to sign-off the tire as 'in limits'. She was doing what Maintenance Control was telling her. I told her not to sign it off; do not let Maintenance Control talk you into doing something that is not legal. There were two Air Carrier mechanics that came. Neither one had measured the damage or had the AMM reference showing allowable damage. Anyway I told them and Maintenance Control I was going to call the FAA three days later. My intention was to get the Air Carrier Contract Manager on a conference call with their Quality Control and the FAA and discuss it to see what can be done about Maintenance Control having some oversight; as this happens too often. Three days later; I was contacted by the Air Carrier Contract Manager and we discussed it.The one thing on my count that may have been done wrong is the way the short sign-off was done. Since I asked Maintenance Control how to do it and they said; 'do not put anything in the logbook'; I may have done it different than what their General Maintenance (or Procedures) Manual (GMM) says to. Also; I did not include 'EMB-145' before the AMM reference which may be mandatory per their GMM. Also; I used the standard six digit AMM reference and their GMM may require a longer AMM reference. I do not have access to their GMM and as always; rely on their Maintenance Control to guide through their proper procedures. Even though I believe that short signing the logbook was the correct thing to do; I did so without the permission of Maintenance Control. I was told that the aircraft was signed-off for revenue flight. This is very surprising to me since I made sure the Air Carrier mechanics; Maintenance Control and the Captain knew I was going to discuss this with the FAA later and I expressed that the puncture in the tire was very deep and possible almost through the tire. Per our conversation; the reference I used was the correct one; AMM 32-49-01. I was called back later to sign-off Item One; and then I made a second log entry saying 'reference log page XXXX; Item-1; left MLG Inboard tire has a piece of metal stuck in it'. Air Carrier Mechanic was to change the tire on this Block. Maintenance Control said they had a reference for the depth measurements of the tire cord. I told them I don't believe anymanual will reference the depth of the cords; but if they have them; fax them to me. They refaxed over page 607 diagram of the tire which shows the cord but does not reference the depth of each cord. The damage; being a puncture; does not have access to view the cords. The AMM does not specifically give limits for punctures; so you have to use the cut limits which state damage is only allowed to go through one ply. The first ply is usually approx 1/32' of an inch below the groove. The damage was just over 3/4' of an inch deep. The tire had good tread; so the damage was just over 1/2 inch below the groove. Yes; there is no way to verify if it went through one ply; unless you had the measurements for the plies; but good judgment says it went through many if not most of the plies; maybe almost through the whole tire. Maintenance Control was aware of the measurements and the 'Out of limits' condition. When I was called back over to sign-off the logbook; I realized that they did not change the tire. I told the Air Carrier mechanics not to sign it off. They had not even measured the damage. They were going off of what Maintenance Control was telling them. They did not even have the Maintenance Manual (M/M) reference with them. I had to go back to the [Maintenance] Shop and dig the AMM out of the trash for them. I went over the limits with them. The Air Carrier Mechanic called Maintenance Control; and the Maintenance Control (I take it he was the Maintenance Director) wanted to talk to me. I told him it was so far out of limits that there is no way he should be trying to throw these guys under the bus to sign it off. Unfortunately Maintenance Control did not have any documentation to show what the depth measurements were for each ply; which would have been the only way to definitively determined how many plies the damage went through.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.