Narrative:

During days of extreme high temperatures; heat buildup in the aft equipment bay on the CRJ200 has caused cargo fire bottles to partially thermal discharge; thus causing the cargo fire bottle low EICAS message. In order to combat this problem we have rented portable air conditioning units; along with generators; in ZZZ that have ducts that can be placed in the aft equipment bay. Effective immediately; maintenance control will be tasked with daily monitoring of the fleet on the ground in ZZZ. If the ambient air temperature reaches 95 degrees and an aircraft (CRJ200 only) is sitting on the ground for 1 hour or more (scheduled or unscheduled); maintenance control will contact the ZZZ lead technician and advise him that the aircraft requires cooling of the aft equipment bay. Maintenance control will generate an order indicating that the aircraft requires cooling of the aft equipment bay. Maintenance in ZZZ will make every effort to ensure that the aircraft receives cooling. The above memo was sent to us in maintenance control. The procedures mentioned in the memo could cover up a potential bleed air leak. The fire bottles are made to operate in normal temperatures even on hot days. I will not be a party to cover-up discrepancies. Using ground air to cool an aft equipment bay can mask a bleed air leak on the ground allowing it to go unnoticed and allow the plane to continue revenue service with a bleed leak; causing downline cancellations and delays or worse. I will not take part in this cover-up. A more comprehensive inspection program of the bleed air duct system for leaks. Callback conversation with reporter revealed the following information: reporter states he is in maintenance control and believes the maintenance directive does not address the issue of pneumatic bleed leaks. The overheat detection system for hot bleed air leaks may not be triggered by a bleed leak; but; the cumulative heat build-up in the aft equipment bay will cause a thermal discharge in the cargo fire bottles. Reporter also feels if his company would at least require that mechanics check for pneumatic leaks before attaching the ground air conditioning cart to the aircraft; this would satisfy the issue of known bleed leaks in that compartment area. The cargo fire bottles have a visual pressure gage on each bottle; as well as the EICAS system cockpit warning fire bottle low pressure indication.

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Original NASA ASRS Text

Title: CRJ-200 CARGO FIRE BOTTLES TEND TO PARTIALLY DISCHARGE IN HIGH HEAT CONDITIONS. MECHANIC BELIEVES COMPANY DIRECTIVE TO ADDRESS ISSUE IS UNSAFE.

Narrative: DURING DAYS OF EXTREME HIGH TEMPS; HEAT BUILDUP IN THE AFT EQUIP BAY ON THE CRJ200 HAS CAUSED CARGO FIRE BOTTLES TO PARTIALLY THERMAL DISCHARGE; THUS CAUSING THE CARGO FIRE BOTTLE LOW EICAS MESSAGE. IN ORDER TO COMBAT THIS PROB WE HAVE RENTED PORTABLE AIR CONDITIONING UNITS; ALONG WITH GENERATORS; IN ZZZ THAT HAVE DUCTS THAT CAN BE PLACED IN THE AFT EQUIP BAY. EFFECTIVE IMMEDIATELY; MAINT CTL WILL BE TASKED WITH DAILY MONITORING OF THE FLEET ON THE GND IN ZZZ. IF THE AMBIENT AIR TEMP REACHES 95 DEGS AND AN ACFT (CRJ200 ONLY) IS SITTING ON THE GND FOR 1 HR OR MORE (SCHEDULED OR UNSCHEDULED); MAINT CTL WILL CONTACT THE ZZZ LEAD TECHNICIAN AND ADVISE HIM THAT THE ACFT REQUIRES COOLING OF THE AFT EQUIP BAY. MAINT CTL WILL GENERATE AN ORDER INDICATING THAT THE ACFT REQUIRES COOLING OF THE AFT EQUIP BAY. MAINT IN ZZZ WILL MAKE EVERY EFFORT TO ENSURE THAT THE ACFT RECEIVES COOLING. THE ABOVE MEMO WAS SENT TO US IN MAINT CTL. THE PROCS MENTIONED IN THE MEMO COULD COVER UP A POTENTIAL BLEED AIR LEAK. THE FIRE BOTTLES ARE MADE TO OPERATE IN NORMAL TEMPS EVEN ON HOT DAYS. I WILL NOT BE A PARTY TO COVER-UP DISCREPANCIES. USING GND AIR TO COOL AN AFT EQUIP BAY CAN MASK A BLEED AIR LEAK ON THE GND ALLOWING IT TO GO UNNOTICED AND ALLOW THE PLANE TO CONTINUE REVENUE SVC WITH A BLEED LEAK; CAUSING DOWNLINE CANCELLATIONS AND DELAYS OR WORSE. I WILL NOT TAKE PART IN THIS COVER-UP. A MORE COMPREHENSIVE INSPECTION PROGRAM OF THE BLEED AIR DUCT SYS FOR LEAKS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATES HE IS IN MAINT CONTROL AND BELIEVES THE MAINT DIRECTIVE DOES NOT ADDRESS THE ISSUE OF PNEUMATIC BLEED LEAKS. THE OVERHEAT DETECTION SYSTEM FOR HOT BLEED AIR LEAKS MAY NOT BE TRIGGERED BY A BLEED LEAK; BUT; THE CUMULATIVE HEAT BUILD-UP IN THE AFT EQUIPMENT BAY WILL CAUSE A THERMAL DISCHARGE IN THE CARGO FIRE BOTTLES. REPORTER ALSO FEELS IF HIS COMPANY WOULD AT LEAST REQUIRE THAT MECHANICS CHECK FOR PNEUMATIC LEAKS BEFORE ATTACHING THE GROUND AIR CONDITIONING CART TO THE ACFT; THIS WOULD SATISFY THE ISSUE OF KNOWN BLEED LEAKS IN THAT COMPARTMENT AREA. THE CARGO FIRE BOTTLES HAVE A VISUAL PRESSURE GAGE ON EACH BOTTLE; AS WELL AS THE EICAS SYSTEM COCKPIT WARNING FIRE BOTTLE LOW PRESSURE INDICATION.

Data retrieved from NASA's ASRS site as of January 2009 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.