Narrative:

A mechanic called me over and pointed at a bleed leak problem. Pack no. 2 heat exchanger; which is right behind the two belly doors where the ground cabin air connector lies; and after that door comes the door for the ground air start. This is on the left side belly directly in front or next to the air intake for pack number 2. The ground connector cabin air door was bent at the hinges which created a good gap around the door allowing the airstream to zip right into the compartment; which in this case was a good thing (again; in my honest opinion) for us today. As we inspected the heat exchanger; maintenance took the cover door off; we spotted a 4 inch bleed connector right below the cabin floor to the heat exchanger that had been loose for a while. Maintenance concluded that it had been loose for a while because the metal colors showed the wear and tear of the extreme bleed heat produced by this leak. The reason why we had not had a heat warning was because the bent door was allowing cold air to prevent it from overheating or causing any other serious problems in flight? Why has this problem gone unnoticed? Because; there is no way to see it in a normal walk around with the APU bleed off and no APU air on. The pack would overheat the same way it does on a very hot summer day and then trip off. In this case; the cold air coming from the outside (through the bent door) in-flight prevented the pack from tripping off; but it continued to work without reaching the trip off temperature. Now; having said that; for all effects and purpose; the aircraft was basically operating on one pack (number 2) and we were operating at FL260 due to moderate turbulence over florida and some over cuba at higher levels and unaware of this issue. Don't know if the cabin would have sustained pressurization at higher flight levels like FL350 to 390 with the amount of air leaking out; which on the ground was considerable enough so as not to have any noticeable air suction at the pack inlet scoop. Run the APU before performing a walk around; look at the external cabin door access connector for a bent door and with the APU (both packs running) and check for abnormal air leakage. APU should be running during walk around; and during walk around; check for leaks. A bleed leak can be a serious thing! Even though there is an overheat sensor; there is no fire sensors or extinguishers in that compartment. These connectors are coming loose with wear and tear. They are hard to spot; but just open the access door with APU running and both packs working. Also check the pack inlet door. If there is no suction going in and the pack is running...you have an internal leak.

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Original NASA ASRS Text

Title: A319 Captain reports that a bent cabin air access door leads to the discovery of a leaking bleed air duct.

Narrative: A Mechanic called me over and pointed at a bleed leak problem. Pack No. 2 Heat Exchanger; which is right behind the two belly doors where the Ground Cabin Air connector lies; and after that door comes the door for the Ground Air start. This is on the left side belly directly in front or next to the Air Intake for Pack Number 2. The Ground Connector Cabin air door was bent at the hinges which created a good gap around the door allowing the airstream to zip right into the compartment; which in this case was a good thing (again; in my honest opinion) for us today. As we inspected the Heat Exchanger; Maintenance took the cover door off; we spotted a 4 inch bleed connector right below the cabin floor to the heat exchanger that had been loose for a while. Maintenance concluded that it had been loose for a while because the metal colors showed the wear and tear of the extreme bleed heat produced by this leak. The reason why we had not had a heat warning was because the bent door was allowing cold air to prevent it from overheating or causing any other serious problems in flight? Why has this problem gone unnoticed? Because; there is no way to see it in a normal walk around with the APU Bleed Off and no APU Air ON. The pack would overheat the same way it does on a very hot summer day and then trip off. In this case; the cold air coming from the outside (through the bent door) in-flight prevented the pack from tripping off; but it continued to work without reaching the trip off temperature. Now; having said that; for all effects and purpose; the aircraft was basically operating on one pack (number 2) and we were operating at FL260 due to Moderate Turbulence over Florida and some over Cuba at higher levels and unaware of this issue. Don't know if the Cabin would have sustained pressurization at higher Flight levels like FL350 to 390 with the amount of air leaking out; which on the ground was considerable enough so as not to have any noticeable air suction at the pack inlet scoop. Run the APU before performing a walk around; look at the external cabin door access connector for a bent door and with the APU (both packs running) and check for abnormal air leakage. APU should be running during walk around; and during walk around; check for leaks. A bleed leak can be a serious thing! Even Though there is an overheat sensor; there is no fire sensors or extinguishers in that compartment. These connectors are coming loose with wear and tear. They are hard to spot; but just open the access door with APU running and both packs working. Also check the pack inlet door. If there is no suction going in and the pack is running...YOU HAVE AN INTERNAL LEAK.

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.