ASRS Examples
Everyone in the aviation community has the ability to affect safety. The examples below are taken from the ASRS and show that there are many players in the safety value chain. These examples are provided throughout the book to illustrate issues in the actual words of those commercial aviation professionals who experienced a safety event. The italicized portions that follow are the actual quotes by aviation professionals to report the situation that they faced and ones they experienced. Following each narrative, there is a question posed to the reader that connects the report with the content of the chapter.
Maintenance
Title: Hydraulic System: crossed pressure lines
While troubleshooting the cause of two previous replacements of hydraulic system reservoir pressurization manifold, a Maintenance found that “crisscrossed” pneumatic pressure lines were preventing pressurization of the Blue hydraulic system.
After discovering that we were going to install [an A-319’s] hydraulic pressure manifold for the third time, I decided to figure out why the folds were not pressurizing the Blue hydraulic reservoir to 50 PS I. After hours of troubleshooting the problem, I found that the left engine supply line in the left wheel well was connected to a “tee” fitting that supplies all three hydraulic reservoirs thereby bypassing the pre manifold completely and probably over-pressurizing the reservoirs.
The Blue system pneumatic supply line (going to the hydraulic reservoir) was connected to a “union” [fitting], which is the manifold supply connection from the left engine thereby never supplying pneumatic pressure to the Blue reservoir. So, the lines were crisscrossed.
Both “B” nuts will fit on either connection and there is plenty of room for the lines to cross and not chafe on anything. It appeared that neither line had been replaced . . . . When an Airbus comes into the hangar, a low-pressure check of each Green, Yellow and Blue hydraulic reservoir’s head pressure is performed using ground service air. Although the Blue reservoir’s head pressure was above the 22 PSI that sets off warnings in the cockpit, it was not possible to increase the head pressure by applying service air to see if the reservoir pressurization manifold was functioning.
When the Blue head pressure did not respond, the thought was that the manifold was again at fault. The aircraft had been flying for some time with the lines crossed, but since the Blue hydraulic reservoir head pressure never went below 22 PSI, no discrepancies were noted. Maintenance history showed the aircraft did have hydraulic issues with the Green and Yellow systems oozing hydraulic fluid, but those discrepancies were probably caused by high reservoir head pressures from the crossed pneumatic supply lines.
Question for the reader: What are the ethical implications of not looking for the root issues behind recurring maintenance problems?
Last Completed Projects
| topic title | academic level | Writer | delivered |
|---|