Narrative:

While deplaning flight at ZZZ2; the purser pointed out a missing panel on top of the #1 engine. The piece is approximately 3 x 25 inches on the inboard side; against and paralleling the pylon. The panel was in place when we departed ZZZ and it is unknown when it was lost. Local maintenance brought out a ladder and it was discovered that the metal had ripped off; with the screws holding the side of the panel on the pylon side still in place with metal under and around them. This piece is only attached along that side. Several (approximately 3-4 inch) curved scratches were evident on the pylon; indicating that the panel had bent up and flapped several times before departing. Could not find any other damage to the airplane. A similar but longer (approximately 36 inches) panel is immediately to the rear of the missing panel. It was still attached along its edge down the pylon; but the first 4 inches is not secured with screws and could easily be flexed by hand. This front edge is normally overlapped by the front panel. Maintenance asked for pictures to verify what panel was missing and eventually discovered a reference allowing for the open space to be covered with a triple layer of speed tape; allowing for up to 50 flight hours. My primary concern was the remaining long panel with the unsecured front edge if the tape failed; would this allow the wind stream to damage the long panel; potentially causing damage to the wing or flaps? I inquired with the local mechanic and with maintenance about the likelihood of air pressure coming out from the engine; through the hole and pushing the tape free. Both assured me that there should not be any significant air flow through this hole that could force the tape free. We departed ZZZ2 and passing approximately 13;000 ft received a call from the purser saying that passengers had reported that the tape was loose. We immediately slowed the airplane and prepared for a return to ZZZ2. Without knowing if the long panel was at risk of being damaged; I declared an emergency; received vectors to the VOR final (night; mountainous terrain) and landed uneventfully; slightly overweight (3;000 pounds). Back at the gate I examined the tape. It was still attached along the front and front half of the side along the pylon. It had a bend in the middle indicating that pressure coming out of the hole had forced it up. Supplemental information from acn 824612: ATC vectored us for the VOR 22 approach in VMC; which we elected to do for terrain separation; with it being night. Callback conversation with reporter acn 824489 revealed the following information: reporter stated the torn section of the panel was below the leading edge. He was informed by their maintenance control the panel material use to be made of stainless steel; but now are made of aluminum. Reporter stated panel was more of a rectangular shape and not round.

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Original NASA ASRS Text

Title: After arrival; a Captain and First Officer report their A320 Cabin Attendant pointed out a missing panel on top of the #1 engine. Metal had ripped off; with screws holding the side of the panel in place; with metal under and around the screws. Tape was applied to the engine in place of the missing panel but it became loose after takeoff forcing a return to land.

Narrative: While deplaning flight at ZZZ2; the Purser pointed out a missing panel on top of the #1 engine. The piece is approximately 3 x 25 inches on the inboard side; against and paralleling the pylon. The panel was in place when we departed ZZZ and it is unknown when it was lost. Local Maintenance brought out a ladder and it was discovered that the metal had ripped off; with the screws holding the side of the panel on the pylon side still in place with metal under and around them. This piece is only attached along that side. Several (approximately 3-4 inch) curved scratches were evident on the pylon; indicating that the panel had bent up and flapped several times before departing. Could not find any other damage to the airplane. A similar but longer (approximately 36 inches) panel is immediately to the rear of the missing panel. It was still attached along its edge down the pylon; but the first 4 inches is not secured with screws and could easily be flexed by hand. This front edge is normally overlapped by the front panel. Maintenance asked for pictures to verify what panel was missing and eventually discovered a reference allowing for the open space to be covered with a triple layer of speed tape; allowing for up to 50 flight hours. My primary concern was the remaining long panel with the unsecured front edge If the tape failed; would this allow the wind stream to damage the long panel; potentially causing damage to the wing or flaps? I inquired with the Local Mechanic and with Maintenance about the likelihood of air pressure coming out from the engine; through the hole and pushing the tape free. Both assured me that there should not be any significant air flow through this hole that could force the tape free. We departed ZZZ2 and passing approximately 13;000 FT received a call from the Purser saying that passengers had reported that the tape was loose. We immediately slowed the airplane and prepared for a return to ZZZ2. without knowing if the long panel was at risk of being damaged; I declared an emergency; received vectors to the VOR final (night; mountainous terrain) and landed uneventfully; slightly overweight (3;000 LBS). Back at the gate I examined the tape. It was still attached along the front and front half of the side along the pylon. It had a bend in the middle indicating that pressure coming out of the hole had forced it up. Supplemental information from ACN 824612: ATC vectored us for the VOR 22 approach in VMC; which we elected to do for terrain separation; with it being night. Callback conversation with Reporter ACN 824489 revealed the following information: Reporter stated the torn section of the panel was below the leading edge. He was informed by their maintenance control the panel material use to be made of stainless steel; but now are made of aluminum. Reporter stated panel was more of a rectangular shape and not round.

Data retrieved from NASA's ASRS site as of April 2012 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.