Narrative:

At the time of design/development of the GP7200-powered airbus A380 aircraft; airbus required a 'scupper' or drip pan; underneath the engine pylon raceway fluid connection fittings. The outlet; or drain; of this drip pan; which is exposed to prevailing nacelle pressures; is connected to the zone 'a' pylon/strut drain line; that leads from the interior floor of the engine pylon (or 'strut') down to the engine-mounted [lower] drain mast; and open to atmosphere at the lower end of the drain mast. During normal engine operation; the nacelle will be pressurized with respect to ambient atmospheric pressure; due to the operation of the core compartment cooling system and other factors. The interior of the engine pylon [compartments]; will remain at ambient atmospheric pressure. By connecting the [scupper] drip pan drain [line] to the [pylon/strut] zone 'a' drain [line running down] inside the nacelle; the nacelle [pressurized] air will flow not only through the [scupper] drip pan drain exit towards the [lower] drain mast; but also 'upwards'; into the pylon interior cavities. [One] fire zone (the engine nacelle area); is therefore connected to a flammable fluid leakage zone (the pylon interior).this violates 14 crash fire rescue equipment 25.1187 (c); which states: '(c) no ventilation opening may be where it would allow the entry of flammable fluids; vapors; or flame from other zones.' it is the flammable fluids and vapors aspect of this regulation that is of most concern. Although the probability of an accident or incident occurring from this situation is low; (it would take both a flammable fluid or vapor source in the [engine] nacelle and an ignition source in the pylon or strut simultaneously); the results could be catastrophic. Airbus and general electric aircraft engines management were advised of this concern in writing at the time of design; well before engine and aircraft certification. Both management teams chose to ignore and disregard this concern and issue. Determine if this configuration still exists on the applicable aircraft (or any other airbus aircraft); and if so; issue airworthiness directives (ad) as required to the aircraft and engine manufacturers; as applicable; to correct the situation.

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Original NASA ASRS Text

Title: An Aircraft Maintenance Technician (AMT) reports his concerns about a design issue involving fluid drain lines in the pylon and engine nacelles of A380 aircraft equipped with GP7200 series engines. Technician notes that connecting the ambient pressure pylon drain line with the pressurized engine nacelle scupper pan drain line is not in compliance with 14CFR 25.1187 (c) and would 'allow the entry of flammable fluids; vapors; or flame from other zones.'

Narrative: At the time of design/development of the GP7200-powered Airbus A380 aircraft; Airbus required a 'scupper' or drip pan; underneath the engine pylon raceway fluid connection fittings. The outlet; or drain; of this drip pan; which is exposed to prevailing nacelle pressures; is connected to the Zone 'A' pylon/strut drain line; that leads from the interior floor of the engine pylon (or 'strut') down to the engine-mounted [lower] drain mast; and open to atmosphere at the lower end of the drain mast. During normal engine operation; the nacelle will be pressurized with respect to ambient atmospheric pressure; due to the operation of the Core Compartment Cooling system and other factors. The interior of the engine pylon [compartments]; will remain at ambient atmospheric pressure. By connecting the [scupper] drip pan drain [line] to the [pylon/strut] Zone 'A' drain [line running down] inside the nacelle; the nacelle [pressurized] air will flow not only through the [scupper] drip pan drain exit towards the [lower] drain mast; but also 'upwards'; into the pylon interior cavities. [One] Fire Zone (the engine nacelle area); is therefore connected to a Flammable Fluid Leakage Zone (the pylon interior).This violates 14 CFR 25.1187 (c); which states: '(c) No ventilation opening may be where it would allow the entry of flammable fluids; vapors; or flame from other zones.' It is the flammable fluids and vapors aspect of this regulation that is of most concern. Although the probability of an accident or incident occurring from this situation is low; (it would take both a flammable fluid or vapor source in the [engine] nacelle and an ignition source in the pylon or strut simultaneously); the results could be catastrophic. Airbus and General Electric Aircraft Engines Management were advised of this concern in writing at the time of design; well before engine and aircraft certification. Both Management teams chose to ignore and disregard this concern and issue. Determine if this configuration still exists on the applicable aircraft (or any other Airbus aircraft); and if so; issue Airworthiness Directives (AD) as required to the Aircraft and Engine manufacturers; as applicable; to correct the situation.

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.