The story of how physical and mental fatigue
contributed to a familiar, yet fatal mistake.
A 30-year-old commercial pilot and a passenger left Plant City, Florida, on a Saturday morning in March for a time-building trip to Las Vegas. The plan was to return around the middle of the coming week, depending on weather. The pilot had rented a Diamond DA40 for the trip, a four-seater with a 180 hp engine, a gliderlike wing of nearly 40-foot span and a cross-country speed of around 150 knots. The three-year-old airplane was equipped with a Garmin G1000 glass panel, a system with which the pilot had several hundred hours of experience.
Leaving Plant City at 1100 EST and stopping at Mobile, Alabama, they reached Huntsville, Texas, at 1920 CST. At this point they had been airborne for 7½ hours, and the pilot had put in an additional hour being checked out in the DA40 before their departure. They had originally intended to continue after refueling, but after discussing how tired they both felt, they decided to stay the night at Huntsville.
They were back at the airport early and took off at 0715. At some point in the middle of that afternoon, having apparently stopped to refuel somewhere in southeastern New Mexico, they ate, refueled again and filed two flight plans at Sedona, Arizona. Las Vegas had apparently lost its charm; they were headed instead for Arcata, California, with a stop at Palmdale, near Los Angeles. They took off at 1730 MST, overflew Palmdale and landed at Bakersfield at 1841 PST. At this point they had most likely been airborne for 8½ of the past 15 hours, and had covered around 2,000 nm since leaving Plant City the previous day.
At 1936 PST, they left Bakersfield for Arcata, picking up an IFR clearance once airborne.
About half an hour after takeoff, the pilot called Oakland Flight Watch to inquire about turbulence reports. The specialist responded with a general update on unsettled weather affecting central and northern California. There was icing in clouds, but the freezing level was high enough that it should not pose a threat to the flight. An area of moderate precipitation was just ahead, but rain would become more scattered as the flight advanced northwestward. There were some reports of moderate turbulence. Arcata was reporting nine miles’ visibility, with scattered clouds at 5,000 feet and an overcast layer at 9,500.
As the flight neared Arcata, the pilot switched from Oakland to Seattle Center. After a few minutes the controller, apparently noticing that the Diamond had strayed from its assigned altitude, first gave the pilot the current altimeter setting and then asked his altitude. He replied that he was at 9,300 feet. The controller reminded the pilot that his assigned altitude was 10,000 feet, and asked whether he was “having difficulty.” The pilot replied that he was experiencing lots of updrafts and downdrafts and moderate to severe turbulence, but he was correcting to his assigned altitude.
Shortly afterwards, the controller cleared the flight to descend to 9,000 feet. There followed some discussion about which of Arcata’s several instrument approaches the pilot wished to use; he selected the Runway 14 RNAV/GPS, an overwater approach from the north, just off the coastline. The controller cleared the pilot direct to CULDU, the initial approach fix, which is 12.4 miles northwest of the airport. The controller spelled out the name of the fix phonetically twice before the pilot, saying that it was “really turbulent right now,” asked if he could “get back” to the controller for the information. He was back after 15 seconds, and again the controller spelled out the name and repeated that it was the initial approach fix — in other words, the pilot should not have to hunt for it; it would be displayed in any depiction of the approach.
There was a long silence — 80 seconds — before the pilot returned to ask the controller to verify the ID, which he, the pilot, now misspelled as CUDLU. The controller corrected the error, and the pilot at last said, “OK, I got it this time.”
A few minutes later, the controller cleared the flight down to 8,000, warning the pilot that this was the minimum IFR altitude and that it “would be bad” if he got below it. The controller also advised the pilot that he would be encountering moderate to heavy rain along the approach.
