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A pilot reports maintenance seemed to de-activate an active; primary; fully operable left pack and right recirculation fan for excessive air noise in the cockpit and cabin on their B757-200. A previous inspection noted a blocked air conditioning duct exceeded the velocity limits and recommended duct cleaning that required multi-shifts.
| Attributes | |
| ACN | 931763 |
| Time | |
| Date | 201102 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | Marginal |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Air Conditioning Distribution Ducting Clamps Connectors |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 250 Flight Crew Total 15000 Flight Crew Type 6000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural MEL Deviation - Procedural Published Material / Policy |
Narrative:
While flight planning on a B757-200; we noticed a log history of excessive air noise in the cockpit and parts of cabin. They deferred the left pack and the right recirculation fan. I started looking further in the log history; and saw that two days earlier an inspection per maintenance manual (MM 21-22-00) found a blockage that exceeded the velocity limits; and recommended duct cleaning that required multi-shifts.my concern was that the reason for the excessive noise was not a fault of the pack or the recirculation fan. Yet; they seemed to deactivate an active; primary; fully operable system to deal with another write-up (excessive noise). The problem was clearly a blocked duct that the paperwork showed exceeded limits; not a pack or a fan. There was prior refusal due to this [deferral]; prior to this flight being assigned this aircraft.
Original NASA ASRS Text
Title: A pilot reports Maintenance seemed to de-activate an active; primary; fully operable left pack and right recirculation fan for excessive air noise in the cockpit and cabin on their B757-200. A previous inspection noted a blocked air conditioning duct exceeded the velocity limits and recommended duct cleaning that required multi-shifts.
Narrative: While flight planning on a B757-200; we noticed a Log history of excessive air noise in the cockpit and parts of cabin. They deferred the Left Pack and the Right Recirculation fan. I started looking further in the Log history; and saw that two days earlier an Inspection per Maintenance Manual (MM 21-22-00) found a blockage that exceeded the velocity limits; and recommended duct cleaning that required multi-shifts.My concern was that the reason for the excessive noise was not a fault of the Pack or the Recirculation fan. Yet; they seemed to deactivate an active; primary; fully operable system to deal with another write-up (excessive noise). The problem was clearly a blocked duct that the paperwork showed exceeded limits; not a pack or a fan. There was prior refusal due to this [deferral]; prior to this flight being assigned this aircraft.
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.