A Busy Time in the FCLP Pattern

The plane was flying, but it was not the Hornet I knew.

Developing routines and habits are the cornerstones for survival in aviation. We practice and practice. Whether it's learning emergency procedures in the simulator or flying the FCLP pattern, repetition builds good patterns. Unfortunately, bad habits can be learned and reinforced as easily as good ones.

I was about halfway through the CQ phase at the FA-18 FRS in Lemoore. By this time, the briefs were "standard," the man-ups were "standard," and while the ball flying may not have been all that pretty, it, too, was becoming "standard."

One night, we were flying the VFR pattern, and things were moving along smoothly. Alter two bounces, I had Betty telling me about some sort of flight-control problem. A quick check of the flight-control system (FCS) page revealed a single "X" in channel 4 of the right stabilator. The Hornet graphically displays the FCS' status. If any component stops working, an "X" appears on the display to indicate it is Failed or degraded. The Hornet's FCS has several levels of redundancy built into it, allowing it to maintain normal handling qualities even if the system is not operating at 100 percent.

Also, if a failure indication appears, the pilot can reset the FCS to clear the fault. If the failure is a transient or false indication, then the reset will return the FCS to full operating capability.

After seeing the "X" and finding no other indications of a problem, I reset the FCS. As I expected, the system reset. Just another stray electron in the system, I figured.

With the next touch-and-go, however, I realized that my assessment of the problem was not entirely correct. Climbing through 300 feet, I felt the jet shudder and the nose pitch down. I say I felt this because I wasn't looking at the HUD; instead, I was looking for my interval. When I did peek at the HUD, I didn't like what it was telling me. The velocity vector was well below the horizon with less than 300 feet. I jammed the throttles up to military, pulled the stick into my lap, and reached for the ejection handle, while giving the jet all the nose-up trim it would take.

Betty was screaming, "Flight controls, fight controls!" I bottomed out at 100 feet. As the velocity vector broke the horizon, and the VSI went from negative to positive, I peeked at the left digital display indicator (DDI) and was not too thrilled to see the cause of my problem: MECH ON.

The Hornet's FCS had degraded to a mode where the flight-control computers were no longer operating. The normal digital inputs were no longer being supplied to the stabilator actuators; rather, a direct mechanical link between the stick and stabs was controlling the jet.

I quickly told tower I would be climbing through the pattern up to 2,500 feet. The plane was flying, but it was not the Hornet I knew. Having trimmed full nose up in the recovery, and without the full assistance of the flight-control computers, I was fighting a severe longitudinal, pilot-induced oscillation (PIO). After chasing the horizon for a few minutes and giving myself vertigo, I managed to calm things down and let paddles and base know what was going on.

Following NATOPS, I transitioned to half-flaps, which improved the PIO problem, and started climbing before trying to reset the FCS. Being fat on gas, I climbed to 10,000 feet before resetting the system, not wanting to experience another low-altitude MECH reversion. The reset was successful, and I set up for a half-flap straight-in approach. About two seconds after weight-on-wheels, the stabs X'ed out again.

Maintenance duplicated the problem on deck several times but couldn't determine the cause. The mechs replaced both flight-control computers and both stab actuators, which we submitted for an engineering investigation.

As I reviewed the circumstances leading up to this event, I noticed how some of my habits made this situation worse than it needed to be. In my limited time flying the Hornet, I had experienced several flight-control cautions and associated "X's" that cleared with a simple system reset. I assumed the initial indication I received that night was another transient anomaly and felt comfortable continuing after the problem had cleared.

While there are times when you have to solve a problem on your own, this really wasn't one of them. There were plenty of outside sources to confer with and no reason not to let base or paddles know what was going on before deciding to continue.

I had also become overconfident in how I was flying the FCLP pattern. Instead of climbing away from the deck at full power until approaching pattern altitude, I was reducing power passing 200 feet and reducing the climb angle, resulting in fairly low rates of climb. Since the reversion to MECH results in approximately a 10-degree nose-down pitch, I could have avoided hurling myself toward the ground by not getting into the habit of lazily climbing to pattern altitude off a touch-and-go.

Lt. Spence flies with VFA-82.

COPYRIGHT 2000 U.S. Naval Safety Center
COPYRIGHT 2004 Gale Group