Not Seeing The Forest For The Trees

STORY BY LT NATHAN RICE, HSL-49

An SH-60B Sea Hawk helicopter assigned to the Helicopter Anti-Submarine Squadron Light (HSL-49) is flown during a routine mission. (Photo courtesy of the U.S. Navy)

An SH-60B Sea Hawk helicopter assigned to the Helicopter Anti-Submarine Squadron Light (HSL-49) is flown during a routine mission. (Photo courtesy of the U.S. Navy)

Things were smooth during the fourth month of my HSL-49 Helicopter Aircraft Commander (HAC) cruise. It was a 4th Fleet Counter Transnational Organized Crime (CTOC) deployment embarked in USS Gary (FFG 51), and the detachment was running astonishingly well. Our officer in charge (OIC) had recently called everyone together for a few meetings about complacency. We hadn’t run into any major problems, but we were in the stretch of cruise where we felt confident. Things were good.

Upon waking for my noon to 8 p.m. alert shift, I was informed that we would be launching to search for what might be a self-propelled semi-submersible (SPSS) in the area. Crown jewel or unicorn, it was a high value target that everyone was getting spooled up (including me, my co-pilot, our aircrewman and Coast Guard observer). We briefed, conducted a preflight check on our trusty SH-60B, spun up and requested green deck.

“Gauges green, cautions clean,” I said when a final visual check of the cockpit looked exactly the same as the previous 96 days at sea. After the landing safety officer (LSO) released the beams of the rapid securing device (RSD) and gave us a green deck, I repeated, “Gauges green, cautions clean.”

As my copilot picked us up into a hover, I noticed that our turbine gas temperature and gas generator turbine speed (TGT and Ng) both seemed higher than normal. They were still in the green range within the vertical instrument display system (VIDS). Everything else looked good. As we came up and aft, away from the flight deck and out of ground effect, both TGT and Ng momentarily fluctuated into amber and then back to green several times.

I thought, “This is a bit high, but we’re in limits. It’s been over a week since I’ve flown Red Stinger 107, maybe she just burns hotter.” We pedal turned into the wind and completed our takeoff. Climbing to 500 feet, I took the controls while my helicopter second pilot (H2P) completed the post-takeoff checklist, including crunching the numbers for the engine health indicator test (HIT) checks. A few moments later and heading in the direction that Gary wanted us to search, my H2P said the HIT checks were calculated within limits. “Good,” I thought, “she’s just burning hotter.”

Twenty minutes into the flight and with no luck yet finding the SPSS, I glanced at the gauges to ensure things were going as well as they seemed. Everything was green and clean, but something was out of place. The No.1 and No.2 ENG ANTI-ICE ON advisory lights were both illuminated.

I remember thinking how weird that was. I could not ever remember seeing them during this phase of flight. I looked up to the overhead console and confirmed that both ENG ANTI-ICE switches were off and the DE-ICE MASTER switch was in manual.

I knew what NATOPS said about determining if there was a malfunctioning anti-ice/start bleed valve, so I figured I could simply pull power to above 94 percent Ng to see if the lights extinguished. However, both 94 percent and 95 percent were still on. There was no change to 96 percent. Puzzled, I reduced collective. I asked my copilot if he had noticed anything I was missing, but he was just as puzzled. Then I told him to pull out the big NATOPS. He read aloud the section in Chapter 2 on how the valves operate and how to determine if they were malfunctioning.

As our troubleshooting progressed, we ensured circuit breakers were in and looked for a rise in TGT after manually selecting engine anti-ice ON for both engines. There was no rise in either engine.

The gauges were all green and well within limits. The HIT check numbers were in. All we had were two advisory lights that should not have been illuminated. I decided that it was very unlikely that both engine anti-ice/start bleed valves were malfunctioning simultaneously. Since the HIT checks were in, it was more than likely a wiring issue. “Maybe the harnesses aren’t properly seated or a cannon plug is loose,” I said.

Since we were not able to fix our dilemma, we did some time-critical ORM and discussed the issue at hand. Whether or not it was a wiring or indication problem, we had to assume the worst by figuring that the valves had somehow failed.

If they had failed in the open position, they would be robbing 18 percent of available torque from each engine. If they had failed in the closed position, we could flame out an engine during low-power settings, such as during practice auto rotations or quick-stops.

Because of the possible power loss, we talked about how we might drop rotor speed while getting into a power-required-exceeds-power-available situation during landing. To alleviate the problem, I said “I’ll take the approach and landing.” We also discussed that being lighter in fuel would help us. The most dangerous part of the flight with this power-loss malfunction would have been during the takeoff, when our fuel tanks had been full.

Concerned with the possible flame out during low power settings, we agreed that we would be cautious with the collective and not do anything aggressive, such as a quick-stop.

We continued the flight and found no sign of the elusive SPSS. Flight quarters was sounded, numbers passed, and my one approach and one landing happened without incident.

After our maintainers inspected the aircraft, they told us we would be shutting down and not relaunching. While in the maintenance shop to log the flight and write up the discrepancy, my copilot started to log the HIT check in the aircraft discrepancy book (ADB).

A minute later, he sheepishly broke the silence and admitted that he was wrong on his earlier HIT check calculations and that both engines were “way out”. In the heat of the alert launch, he subtracted the reference engine temperature from the actual temperature instead of the other way around. I was frustrated with him but more so with me at the sudden realization that engine anti-ice was on for both engines during the entire flight.

Upon further maintenance troubleshooting, we discovered that inexplicably both engine anti-ice valves had failed in the open (or ON) position, regardless of the cockpit switch setting. I had flown nearly three hours as aircraft commander in a degraded aircraft, without ever appreciating what the degradation was.

Even though we broke out the big NATOPS to read through Chapter 2 and used ORM to back ourselves up, I never considered looking in either Chapter 12 or in the pocket checklist. Had I looked in the emergency procedures section of either, we would have been given the answer we needed: land as soon as practical.

The aircraft had been flying fine. I had thought the HIT checks were good and I had never considered it an emergency, but because of the 18 percent power loss we very well could have drooped and lost tail-rotor authority on takeoff.

This was a sobering thought, but more sobering was the complacency I had shown. Ignoring what the aircraft was trying to tell me: “No.1 ENG ANTI-ICE ON” and “No. 2 ENG ANTI-ICE ON”. I could not see the forest for the trees. Overall, it was a wake up call and a great lesson in complacency.