The pilot of a Piper PA-31-325 Navajo that crashed on August 16, 2016, near Northport, Alabama, killing all six on board, had given air traffic control his diagnosis of the problem the airplane was experiencing. Apparently, the pilot didn't believe it was dramatic enough to declare an emergency, and he expressed confidence he'd have no trouble diverting to the airport at Tuscaloosa about 20 miles ahead. When given the option of taking a vector for an airport at three o'clock and just eight miles, the pilot said, “Nah, Tuscaloosa's perfect.” What NTSB investigators learned from airplane maintenance records and a flight instructor who had flown frequently with the pilot raises the possibility that instead of trying to gather current facts and make a current diagnosis, the pilot believed he was experiencing a repeat of an old fuel pump issue that once again could be handled without jeopardizing safety.
The PA-31-325 was manufactured in 1984. The pilot purchased it using a limited liability company on March 14, 2016. He based the airplane at University-Oxford Airport, Oxford, Mississippi. The Navajo had six seats and was powered by two Lycoming TIO-540 engines, each producing 350 horsepower. The airplane had accumulated 3,447.8 flight hours at the time of the accident. The most recent annual inspection had taken place about eight months before the accident. The airplane had been flown 187 hours in those eight months.
The pilot had a private certificate for single-engine and multi-engine land airplanes and an instrument rating. His FAA third-class medical was current. He had logged 749.7 hours, with 48.7 in PA-31 aircraft. His logbook noted two dual instruction flights totaling 2.9 hours on March 17, 2016, three days after the pilot purchased the airplane.
The airplane had four fuel tanks: one inboard and one outboard in each wing. Each side had three fuel pumps: an engine-driven pump, a boost pump, and an emergency pump. According to Piper, the right and left fuel systems are independent and only connect when the crossfeed system is activated. Fuel goes from the wing tanks through the selector valve, through a filter, to the boost pump, through the emergency fuel pump, the firewall shutoff valve, and to the engine-driven fuel pump. The emergency pumps are used during takeoff and landing and when priming the engines. The regular boost pumps operate continuously whenever the master switch is on. Needles in a fuel flow gauge indicate the flow in U.S. gallons per hour for each engine. A dual fuel-pressure gauge displays the pressure in pounds per square inch for each side. Sensing probes activate a warning on an annunciator panel when fuel flow from the main tank stops. There also is a red if a boost pump fails, but Piper says if that happens, “it should not be necessary to turn the emergency fuel pump on unless the pressure falls below 30 psi.”
When interviewed by an NTSB investigator, the flight instructor said he had only flown one flight alone with the pilot in the Navajo and didn't provide emergency procedures training. On more than one occasion he rode with the pilot when passengers were on board, but they didn't do training maneuvers then. He told investigators that he did not know of the pilot receiving Navajo training from anyone else but was aware the pilot had studied the Pilot Operating Handbook and did good, thorough preflights.
The pilot had told the instructor about a flight to South Carolina during which the fuel pressure annunciator light had come on, but there was no loss of fuel pressure. The pilot said he had a mechanic look at the plane, but nothing abnormal was found.
The instructor was with the pilot on a trip to Austin, Texas, and back. After takeoff from Austin, at about 1,000 feet, the right engine acted as if it was going to quit. The engine's fuel pressure was dropping below red line, so the pilot turned on the emergency pump. The pressure came back up. After a few minutes, he turned off the emergency pump, and the pressure started dropping. He put the emergency pump back on and left it on for about 45 minutes. When he again turned off the emergency pump, the pressure stayed up. Subsequently, the pilot took the airplane to a mechanic and had him replace both the right engine's boost pump and the engine-driven pump. That was on July 19, 2016, about 17 flight hours before the accident.
The flight instructor said the airplane burned about 38 to 40 gallons total per hour on average. He knew that the pilot was planning a flight to Florida and on August 10 texted him to ask whether the airplane was okay. The pilot responded that everything was fine but that the screen for the Engine Data Monitor would occasionally flicker or go dark after an hour of use.
The Florida trip — the accident would occur on the return leg — was so the pilot, his wife and two other couples could attend a medical conference in Orlando, Florida. They had flown into Kissimmee Gateway Airport (KISM), and this was the return flight to Oxford, Miss. The pilot filed an IFR flight plan with a cruising altitude of 12,000 feet MSL. At about 8:55 a.m., they were cleared for takeoff. According to Piper, takeoff should be flown using the inboard fuel tanks. Then the pilot is supposed to switch to the outboard tanks and, when the fuel has been used, go back to the inboard tanks. The outboard tanks hold 40 gallons each and the inboards 56 gallons each, for a total of 192 gallons, of which 183.4 are usable. Fuel receipts indicated the airplane carried full fuel when it left Kissimmee.
At about 10:59:42, a little over two hours after takeoff, the flight was at 12,000 feet and being handled by Atlanta Center when the pilot radioed, “Atlanta Center, seven sierra alpha, I may need to make an, a (unclear) a landing. I'm losing my fuel pump.” The controller asked, “...can you make it to Tuscaloosa?” The pilot replied, “Uh, yeah, I should be able to make it to Tuscaloosa.” The controller cleared the pilot direct to the Tuscaloosa Regional Airport (KTCL) and told him to descend to 6,000 feet. The pilot did not respond and, at 11:00:19, the controller radioed, “November four four seven sierra alpha, cleared direct to Tuscaloosa Airport, tango charlie lima, maintain, ah, six thousand.” At 11:00:48, the pilot responded, “I'm cleared direct Tuscaloosa.”
The controller asked if there was anything else the pilot needed and, at 11:01, the pilot said, “Not right now, but I'm working on it, I'm just trying to get her trimmed up, but I just got a lot of manifold pressure loss.” The controller advised, “I also do have an airport over at your three o'clock about eight miles, ah, then Tuscaloosa is dead ahead at, ah, twenty miles.” At 11:01:28, the pilot replied, “Nah, Tuscaloosa's perfect.”
At 11:03:04, the controller advised, “If you can make it to Tuscaloosa, that's great. Ah, I'm gonna put you on Birmingham Approach's frequency and let them handle you, ah, handle you all the way into the airport. Is there anything else you might need from me?” “No,” said the pilot. “I don't believe so. I can go to Birmingham (approach control). We're pretty stable here. I'm just taking it slow.”
The pilot then switched over to Birmingham Approach and, at 11:03:49, radioed that “...I'm at one zero thousand, descending into Tuscaloosa, got a right fuel pump out.” The controller cleared the pilot to 4,000 feet and told him to advise if he needed any assistance. At 11:04:20, the pilot said, “Four thousand, as long as I can take it slow, we'll be fine.”
At 11:06:37, the controller radioed the Navajo to “descend and maintain two thousand three hundred. We just talked to the tower, and they say as long as you can get below two thousand five hundred, you should be able to get the visual.” KTCL had scattered clouds at 2,600 feet, a broken ceiling at 3,600 feet, visibility 10 miles and wind from 170 degrees at 10 knots gusting to 14 knots.
At 11:06:47, the pilot replied, “Roger that, I'm going to two thousand three hundred, and I may be...” The controller transmitted, “November seven sierra alpha, verify two thousand three hundred.” At 11:06:55, the pilot confirmed, “two thousand three hundred,” followed a few seconds later with, “(unintelligible) approach, Tuscaloosa, I may be (unintelligible) danger because, um, I can't believe it. But may be (unintelligible).” The controller asked him to “say again,” and the pilot responded, “I may be losing both engines here (unintelligible).” The pilot followed that with, “I'm not losing both engines, but I lost both fuel pumps.”
The controller advised him that “...the Tuscaloosa Airport now about twelve o'clock and about one three miles, um, any runway you want you can have.”
The pilot asked, “Is there anything even closer?” The controller replied that Tuscaloosa was the closest, and the next closest was behind him, Bibb County Airport at Centreville, Ala.
At 11:08:20, the pilot said, “I'm gonna do my best,” and three seconds later said, “I have no power.”
The controller told the pilot he was “...lined up for, uh, runway three zero at Tuscaloosa right now, it, you just keep it steady, uh, it's about twelve o'clock and about six miles or seven miles now.” The pilot's response: “Okay, I don't know if I'm gonna make it,” followed a few seconds later with, “I'm losing altitude quickly.” The pilot asked for the ceiling, and the controller replied it was 2,500 feet in the area, that he was about five miles from the airport and that radar was showing the airplane at 4,100 feet. The pilot confirmed the altitude and added, “I just don't know if I'm gonna make it.” The controller tried to be reassuring: “...You just hold it up, um, it's, it's twelve o'clock, you're lined up for runway three zero, as soon as you get out of that, uh, ceiling you should get it in sight.”
The pilot was expressing further doubts because of the rate of altitude loss. “I don't know if we can make it on this altitude drop,” he radioed. The controller implored him to “...just try as best you can, please just keep it level,” apparently realizing that the airplane was still in the clouds and how easy it can be for a pilot in distress who may be troubleshooting to become distracted and, possibly, spatially disoriented. The pilot responded, “Keeping it level,” and the controller advised that there was a highway available if he needed it. At 11:11:18, the pilot responded, “I don't know with this ceiling.” About 16 seconds later he added, “I got you, on final now,” apparently indicating that he could see the runway ahead.
At 11:12:29, the Tuscaloosa tower controller told the approach controller via the interphone system that “I've got him in sight, looks like he's got the altitude to make it.” When the approach controller reminded the pilot to lower his landing gear, the pilot responded, “It'll slow me down.” At 11:13:28, the pilot radioed, “Short final now.” That was the last transmission. The airplane impacted trees approximately 1,650 feet short of the approach end of Runway 30 and slammed into the ground. A fire erupted.
The wreckage examination failed to find evidence of preimpact failures or malfunctions that would have interfered with normal engine or airplane systems operations. The propellers for both engines had not been feathered, something pilots would be expected to do when following an emergency checklist and securing a failed engine. Feathering should have helped reduce drag and extend the glide.
All six fuel pumps were recovered and subjected to extensive examination and testing. While one of the pumps showed signs of corrosion attributed to exposure to water from firefighters, none was found to have any problem that would have affected operation during flight.
It was becoming clear to investigators that what the pilot interpreted as a fuel pump problem really was a reflection of fuel starvation due to fuel mismanagement. They noted that the first signs of a problem appeared about the time they calculated the outboard tanks would be empty.
It's possible that the pilot's previous experiences had conditioned him to be especially alert for fuel pressure problems, and he was flying with a preconceived notion that if they appeared he should focus on the fuel pumps rather than taking the time to begin at the beginning in trying to understand what was happening. Believing he had an answer might have led him to not bother with a checklist.
Had he run the “Emergency Procedures Checklist—Engine Failure During Flight,” it would have directed him, before securing the inoperative engine, to check fuel quantity and switch the fuel selector of the inoperative engine to the other tank. Going to the inboard tank on the right engine should have restored fuel and, once that happened, it's likely the pilot would have realized he needed to switch the left side, too, thus preventing power loss of the left engine.
Indeed, the NTSB determined that the probable cause of the accident was the total loss of power in both engines due to fuel starvation as a result of the pilot's fuel mismanagement and his subsequent failure to follow the emergency checklist. Contributing to the pilot's failure to follow the emergency checklist was his lack of emergency procedures training in the accident airplane.
In commenting on this accident, the Safety Board noted that from 2011 to 2015, an average of more than 50 accidents per year were due to fuel management issues. Less than 5 percent were because of a problem with the fuel system. The board declared, “Running out of fuel or starving an engine of fuel is highly preventable.” I think that's what's called an understatement.
Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, visit ntsbreporter.us or write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.