Narrative:

September 2012; regarding outlet guide vanes (ogv) speed tape on B-767-300 aircraft. I've been a pilot at air carrier X for 20-years. I have a degree in aerospace engineering; I have an airframe and powerplant license; and I worked for two years in a rolls royce powerplant engineering department engine overhauls. I am concerned with the inconsistent use and documentation of speed tape on the outlet guide vanes (ogv) on company B-767-300 aircraft. Approximately three days ago; I was flying relief pilot sequence on aircraft X; a B767-300. On two occasions during this sequence I contacted maintenance to inquire as to whether the speed taped ogvs actually use a thicker tape called vibration tape) applied to the engine ogvs (or stator vanes) was within wear limits as there was visible damage. My concern and reason for writing this report is that maintenance gave us two completely different explanations as to the use and required inspection criteria for this repair. I worry that the inconsistency in the interpretation of this repair may cause further issues with the FAA; and worse case [scenario] cause severe engine damage. Here are the two scenarios: flight ZZZ-ZZZZ; aircraft X; right engine was documented in the logbook as having a company engineering variance ogv speed tape repair that required inspection at regular intervals (I believe it was to be inspected at each a-check). A colored placard was in the front of the logbook. During the walk-around inspection; I discovered that much of the tape was damaged and even missing in areas where it had been previously applied. The gate maintenance personnel felt that the damage to the tape was well out of limits; and even questioned whether the use of the tape in this area of the engine was legal or safe. They stated that the tape was only rated to 300-mph; and the flow speeds in this area were much higher. A maintenance supervisor was called. The supervisor was adamant that the ogv repair was within limits and that he'd seen 'hundreds' that were much worse. He stated there was a legal document called a company repair document that was used to repair the ogv. However; when queried about the limits he could not describe them; or even make a guess as to how close the tape was to being out of limits. The supervisor pressured us to take the aircraft; stating that no spares were available; and if we didn't accept the airplane the flight would be cancelled. If we agreed; he'd sign it off and we'd be 'good to go'! The supervisor gave us four pages to the boeing B767 aircraft maintenance manual (amm). Five hit(s); fan frame and case. Fan frame and case; inspection/check; 72-33-00; (16) (d) on page-2 describes the visual limits of the ogv with speed tape. Ironically; these limits seemed to be very restrictive. According to these limits the tape must be smooth and comply with tolerances that would be impossible to measure with the naked eye. The captain asked the supervisor to visually examine the tape in his presence. When the captain pointed out the damage; and the areas where the tape had completely eroded from the ogv; the supervisor agreed they were out of limits; and took the aircraft out of service. Surprisingly; a spare was available; and we departed later that night. To be clear; our issue was not with the legality of the repair; but the condition of the repair. The attitude seems to be that since the tape is inspected at the a-check; it should stay within limits until the next a-check. Obviously; this is flawed logic and the reason [why] pilots do a walk around inspection. Without any guidance on the acceptable wear of the repair; a pilot has no other option but to contact maintenance for an evaluation. Return flight; ZZZZ-ZZZ; on aircraft Y; another B767-300. Arriving at the aircraft; the logbook was not yet available. I performed the walk-around and found speed tape applied to the left engine ogvs; with similar damage and erosion that we had found the night before on aircraft X. As I returned to the jetbridge; I met the mechanic with the logbook in hand. I told him that I needed him to take a look at the ogvs. He immediately opened the logbook and began giving me a similar line of thought that the ogvs were inspected at a-check. However; there was no record in the logbook that speed tape had been applied to the ogvs. There was no repetitive maintenance placard; and it was not in the damage log. The mechanic left to investigate. After I briefed the captain on the situation; he called dispatch. Dispatch spoke with maintenance control and told us there was no record of a speed tape repair to the ogvs. Dispatch felt that maintenance was going to have to remove the tape; document the damage that it was meant to repair; reapply it; and document the repair. Another mechanic arrived; telling us that the speed tape repair was permanent; not a repetitive inspection temporary repair; and therefore did not need to be in the logbook. He became agitated and said there was no way he was going to cancel this flight! The captain agreed that he didn't want to cancel the flight; but that we needed some sort of documentation that told us that the speed tape was legal to be in this engine. The mechanic returned with a maintenance computer print out that showed that the repair was made in september 2012. Why was this not available before? The captain questioned why the same repair at ZZZ the night before required follow-up inspections; with a colored placard in the front of the logbook. The answer was that this was a permanent repair. The captain again called dispatch; and maintenance control was conferenced in. Maintenance control confirmed the second mechanic's explanation; and said that since it was a permanent repair it need not be in the logbook. The mechanic signed-off the logbook; and we flew back to ZZZ. This was a completely different explanation from what we received the night before; and the inconsistency was disturbing. Is this repair permanent or temporary; requiring follow up repetitive inspections? Does it require documentation in the logbook; either way? If it does not require documentation in the logbook; how can I determine if it was a legal repair? Is speed tape application now considered a permanent repair? If it is a permanent repair; and I see damage to the tape; is the integrity of the repair compromised? If it's a temporary repair; and in the logbook; how can I determine how much damage and erosion of tape is acceptable? As pilots; when we see damage to the aircraft; normally there is detailed documentation in the logbook; and often an adhesive tag near the damage referencing the documentation. This issue seems to defy this logic and common practice. With no documentation; how can I accept an aircraft with speed tape of unknown origin applied inside the engine; or anywhere else on the aircraft? When the maximum serviceable limit is described in terms of .04' of an inch (1.0 mm); how can a mechanic sign it off within limits after a visual inspection through the fan blades? Recommend ogv repair with speed tape needs to be clarified and consistently interpreted by company maintenance. Documentation and limits need to be provided to the aircrew so that proper evaluation of repair status and condition of repair can be evaluated during the walk around inspection.

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Original NASA ASRS Text

Title: A Captain and Relief Pilot report at length about the inconsistency in responses from Company Maintenance personnel at two Stations when challenged about speed tape applied to the Outlet Guide Vanes (OGVs) on two CF6-80 engines; on two separate B767-300 aircraft.

Narrative: September 2012; regarding Outlet Guide Vanes (OGV) speed tape on B-767-300 aircraft. I've been a pilot at Air Carrier X for 20-years. I have a degree in Aerospace Engineering; I have an Airframe and Powerplant license; and I worked for two years in a Rolls Royce Powerplant Engineering Department engine overhauls. I am concerned with the inconsistent use and documentation of speed tape on the Outlet Guide Vanes (OGV) on company B-767-300 aircraft. Approximately three days ago; I was flying Relief Pilot sequence on Aircraft X; a B767-300. On two occasions during this sequence I contacted Maintenance to inquire as to whether the speed taped OGVs actually use a thicker tape called vibration tape) applied to the engine OGVs (or Stator Vanes) was within wear limits as there was visible damage. My concern and reason for writing this report is that Maintenance gave us two completely different explanations as to the use and Required Inspection criteria for this repair. I worry that the inconsistency in the interpretation of this repair may cause further issues with the FAA; and worse case [scenario] cause severe engine damage. Here are the two scenarios: Flight ZZZ-ZZZZ; Aircraft X; right engine was documented in the logbook as having a Company Engineering Variance OGV speed tape repair that required inspection at regular intervals (I believe it was to be inspected at each A-Check). A colored placard was in the front of the logbook. During the walk-around inspection; I discovered that much of the tape was damaged and even missing in areas where it had been previously applied. The Gate Maintenance personnel felt that the damage to the tape was well out of limits; and even questioned whether the use of the tape in this area of the engine was legal or safe. They stated that the tape was only rated to 300-MPH; and the flow speeds in this area were much higher. A Maintenance Supervisor was called. The Supervisor was adamant that the OGV repair was within limits and that he'd seen 'hundreds' that were much worse. He stated there was a legal document called a Company Repair Document that was used to repair the OGV. However; when queried about the limits he could not describe them; or even make a guess as to how close the tape was to being out of limits. The Supervisor pressured us to take the aircraft; stating that no spares were available; and if we didn't accept the airplane the flight would be cancelled. If we agreed; he'd sign it off and we'd be 'good to go'! The Supervisor gave us four pages to the Boeing B767 Aircraft Maintenance Manual (AMM). Five hit(s); FAN FRAME AND CASE. FAN FRAME AND CASE; INSPECTION/CHECK; 72-33-00; (16) (d) on Page-2 describes the Visual Limits of the OGV with speed tape. Ironically; these limits seemed to be VERY restrictive. According to these limits the tape must be smooth and comply with tolerances that would be impossible to measure with the naked eye. The Captain asked the Supervisor to visually examine the tape in his presence. When the Captain pointed out the damage; and the areas where the tape had completely eroded from the OGV; the Supervisor agreed they were out of limits; and took the aircraft out of service. Surprisingly; a spare WAS available; and we departed later that night. To be clear; our issue was not with the legality of the repair; but the condition of the repair. The attitude seems to be that since the tape is inspected at the A-Check; it should stay within limits until the next A-Check. Obviously; this is flawed logic and the reason [why] pilots do a walk around inspection. Without any guidance on the acceptable wear of the repair; a pilot has no other option but to contact Maintenance for an evaluation. Return flight; ZZZZ-ZZZ; on Aircraft Y; another B767-300. Arriving at the aircraft; the logbook was not yet available. I performed the walk-around and found speed tape applied to the left engine OGVs; with similar damage and erosion that we had found the night before on Aircraft X. As I returned to the jetbridge; I met the Mechanic with the logbook in hand. I told him that I needed him to take a look at the OGVs. He immediately opened the logbook and began giving me a similar line of thought that the OGVs were inspected at A-Check. HOWEVER; there was NO record in the logbook that speed tape had been applied to the OGVs. There was no Repetitive Maintenance placard; and it was not in the Damage Log. The Mechanic left to investigate. After I briefed the Captain on the situation; he called Dispatch. Dispatch spoke with Maintenance Control and told us there was no record of a speed tape repair to the OGVs. Dispatch felt that Maintenance was going to have to remove the tape; document the damage that it was meant to repair; reapply it; and document the repair. Another Mechanic arrived; telling us that the speed tape repair was PERMANENT; not a Repetitive Inspection Temporary Repair; and therefore did not need to be in the logbook. He became agitated and said there was no way he was going to cancel this flight! The Captain agreed that he didn't want to cancel the flight; but that we needed some sort of documentation that told us that the speed tape was legal to be in this engine. The Mechanic returned with a maintenance computer print out that showed that the repair was made in September 2012. Why was this not available before? The Captain questioned why the same repair at ZZZ the night before required follow-up inspections; with a colored placard in the front of the logbook. The answer was that this was a PERMANENT repair. The Captain again called Dispatch; and Maintenance Control was conferenced in. Maintenance Control confirmed the second Mechanic's explanation; and said that since it was a PERMANENT repair it need not be in the logbook. The Mechanic signed-off the logbook; and we flew back to ZZZ. This was a completely different explanation from what we received the night before; and the inconsistency was disturbing. Is this repair PERMANENT or TEMPORARY; requiring follow up repetitive inspections? Does it require documentation in the logbook; either way? If it does not require documentation in the logbook; how can I determine if it was a legal repair? Is speed tape application now considered a permanent repair? If it is a permanent repair; and I see damage to the tape; is the integrity of the repair compromised? If it's a temporary repair; and in the logbook; how can I determine how much damage and erosion of tape is acceptable? As pilots; when we see damage to the aircraft; normally there is detailed documentation in the logbook; and often an adhesive tag near the damage referencing the documentation. This issue seems to defy this logic and common practice. With no documentation; how can I accept an aircraft with speed tape of unknown origin applied inside the engine; or anywhere else on the aircraft? When the Maximum Serviceable Limit is described in terms of .04' of an inch (1.0 mm); how can a Mechanic sign it off within limits after a Visual Inspection through the fan blades? Recommend OGV repair with speed tape needs to be clarified and consistently interpreted by Company Maintenance. Documentation and limits need to be provided to the aircrew so that proper evaluation of repair status and condition of repair can be evaluated during the walk around inspection.

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.