Tuesday, April 6, 2010
Recognizing You’re In Trouble
Fatigue can cause pilots to fall behind
The pilot was then handed off to Seattle Center; four minutes later, the controller asked for his altitude. The pilot responded that he was indicating 9,300 feet. The controller reminded him that his assigned altitude was 10,000 feet, and asked if the pilot was “having difficulty.” The pilot replied that it was very turbulent, with a lot of “ups and downs” and moderate to severe turbulence. Two minutes later, the controller advised the pilot that other aircraft had reported light to moderate turbulence while on the ILS approach to Arcata. He cleared the pilot to descend to 9,000 feet, and asked if he knew what approach he wanted into Arcata. The pilot replied “negative,” and asked what others were flying. The controller said most pilots coming from the south (as he was) were doing the ILS and circling to runway 14. The pilot started to say, “I guess I can,” but then stopped mid-sentence and said he’d get back to the controller. The controller then advised that a couple pilots flew the RNAV/GPS approach from the north to runway 14. The pilot responded with, “Yeah, we can do an RNAV/GPS for 14.”
The controller cleared the pilot direct to CULDU, spelling out C-U-L-D-U phonetically. The pilot asked the controller to repeat the letters, and the controller obliged, explaining that CULDU was the initial approach fix for the RNAV/GPS approach to runway 14. The pilot then stated that it was “really turbulent right now,” and said he’d call later for “that information.” About 15 seconds later, the pilot transmitted, “All right, can you repeat that fix again?” The controller said the fix was CULDU, that it was the initial approach fix, and spelled it out again.
There was no response for the next 80 seconds. The pilot then asked the controller to verify that the fix was CULDU. The controller advised the pilot that he was “very close,” and that the fix was named CULDU. The controller again spelled it out. The pilot responded, “Okay, I got it this time. Thank you.”
The controller reported that radar showed moderate to heavy precipitation over the Arcata area, and advised the pilot that he’d be in it the whole time he was inbound. The controller then repeated that rain intensity was moderate to heavy.
Three minutes later, the controller cleared the pilot to descend and maintain 8,000 feet, and the pilot read back the clearance. The controller told the pilot that 8,000 feet was the IFR minimum altitude and that the pilot could go above it, but to go below “would be bad.”
Six minutes later, the pilot was cleared to 7,000 feet; two minutes after that, he was cleared to 6,000 feet. The pilot said that he was going to turn toward the west for weather avoidance and then come back to CULDU. The controller cleared him to descend to 5,000 feet, and two minutes later, reminded the pilot to “maintain at or above 5,000 feet, please.” The pilot responded that he was indicating 4,900 feet and was climbing back up.
The pilot was cleared to descend to 4,000 feet, direct to CULDU, and to cross CULDU at or above 4,000 feet, and also was cleared for the RNAV/GPS 14 approach. The pilot read back the clearance, but said “at or below 4,000 feet” instead of “at or above 4,000 feet.” The controller corrected the pilot.
After the pilot was established inbound to the airport, the controller advised that radar service was terminated and that he could switch to the Arcata CTAF. The controller continued to monitor the flight, noticing that the airplane had descended to 1,400 feet before reaching the final approach fix, which had a published minimum crossing altitude of 2,100 feet. Over a 12-minute period, the controller attempted contact with the pilot 10 times. The last Mode C radar target from the airplane was recorded about one-tenth mile from the final approach fix, at 300 feet above the ocean surface. The airplane went into the ocean seven miles from the airport.
Investigators noted that the elapsed time between the beginning of the trip, when the pilot arrived at Plant City Airport in Florida, and the impact with the ocean off Arcata was 42 hours. During that 42-hour period, the pilot accumulated about 22 hours and 45 minutes of flying time, and was “on duty” for 30 hours and 45 minutes. The NTSB determined that the probable cause of this accident was the pilot’s failure to maintain proper altitude and glide path while executing a night instrument approach. Contributing to the accident was the pilot’s fatigue.
Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other NTSB news. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.
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