A Leak in CRM

By LT Marc “Nancy” Pelessone, USN

While deployed on USNS Washington Chambers (T-AKE 11), HSC4’s two aircraft MH-60S detachment prepares for an early morning launch for a vertical replenishment (VERTREP) evolution. We are hundreds of miles off the coast, slowly moving into a connected replenishment (CONREP) position. Our crew completes preflight checks with no issues. We call for green deck and launch shortly after. Within about a minute of launch, our #1 HYD PUMP and #1 RSVR LOW Cautions appear. The near simultaneous occurrence of this is striking. The leak detection and isolation (LDI) logic should have taken care of a leak in the primary tail rotor lines. Could we have a leak elsewhere?

I announce the indications followed by “#1 Primary Servo or Transfer Module Leak, Primary Servo - First Off, Land as Soon as Practicable. Let’s turn back towards the ship.” But confusion ensues. The pilot in command asserts, “No, not first off.” After a brief discussion, along with a nerve-racking turn towards the ship, it becomes clear he is not recently familiar with this emergency procedure. He expected, reasonably so, that we would have had some amount of warning from the #1 RSVR LOW Caution preceding the #1 HYD PUMP Caution. But, with the indications present, our crew delayed performing the appropriate checklist. I pull out the checklist, read the step, and move the switch to “First Off.”

On final for landing, we receive the B/U RSVR LOW Caution. Are we going to have a loss of tail rotor control? Luckily, we do not. Moments after landing tower notifies us that the flight deck is covered in hydraulic fluid. We completely drained the remainder of our backup hydraulic system upon landing. We quickly shutdown. Maintenance inspects the aircraft and confirms both the primary and backup systems were empty.

So what happened?

We learned that, a few days prior the maintenance crew replaced the #1 tail rotor servo. During the replacement, the hydraulic supply line was somehow kinked. This kink, however, was hidden under a label placard, rendering it completely impossible to catch on inspection or preflight. Once the leak started, it drained the #1 Hydraulic System so quickly that the LDI logic switching to the #2 Tail Rotor Servo was not fast enough to prevent the #1 Hydraulic System from draining completely. Once the #1 HYD PUMP Caution appeared, the LDI reopened the #1 Tail Rotor Servo because it assumed the leak was not there. This led to the Backup Hydraulic System being completely depleted as well.

There is a lot to take away from this flight. Both pilots should have been more familiar with the emergency procedure. I knew the procedure, but once challenged by my aircraft commander, my assertiveness quickly vanished. As the pilot with higher situational awareness, I should have taken charge and been more directive with the crew. Along with a communication breakdown in the front, there was a lack of clear communication between the pilots and the aircrewmen, leaving them in the dark regarding the emergency we were fighting. Despite this degraded CRM, we did turn back to the ship and execute our landing without any delay. This emergency initially started as a land as soon as practical, however, treating it like a land as soon as possible may have been our saving grace. Prolonging our airborne troubleshooting could have caused us to experience a loss of tail rotor control, which would have greatly increased the difficulty of a safe landing at sea to a single spot ship.