What happened
On March 10, 2023, at 13:32 UTC, a McDonnell Douglas DC-9-83, registration YV3445, operated by LASER Airlines, departed from Maiquetía International Airport for El Vigía. The aircraft was carrying 63 people, including 54 passengers and nine crew members.
During the climb phase at flight level FL230, the pilot noticed a "pressurization flow" warning light on the annunciator panel. Upon checking the cabin pressure indicator, the first officer confirmed that the cabin pressure was not maintaining normal operating ranges. The crew immediately implemented the Quick Reference Handbook (QRH) procedures for a pressurization failure; however, these actions were ineffective. Consequently, the crew notified Maiquetía Area Control Center (ACC) of their intention to return to the airport due to the malfunction. The aircraft landed safely at Maiquetía at 14:15 UTC with no injuries and no significant damage to the airframe.
The investigation
Investigators examined the aircraft's maintenance records, pilot licenses, and operational documents. A troubleshooting process was conducted in accordance with the Aircraft Maintenance Manual (AMM) to check for pneumatic leaks within the air conditioning system. This inspection revealed a loose duct located between the primary radiator outlet and the air cycle machine (ACM) compressor inlet.
Technical personnel replaced the duct and installed a new clamp (P/N 15J85-312). Following the repair, the right-side air conditioning system was tested and functioned satisfactorily.