Pilot Fatigue Woven Through Circumstances of FedEx Crash

Safety board calls for improved color vision tests and pilot screening

Fatigue can defeat pilots’ proven performance records, progressive company policies and proven procedures.

The object lesson comes from the July 26, 2002, collision with trees on final approach of a Federal Express (FedEx) B727 cargo jet at Tallahassee, Fla. The three pilots survived the crash, but their airplane was destroyed.

The fatigue factor was woven throughout the National Transportation Safety Board (NTSB) final hearing on the case last week.

“Much more work needs to be done on the fatigue issue, especially on the back side of the clock,” said NTSB Member John Goglia. The “back side of the clock” is the expression often used to describe the time from midnight to about six a.m., when the human body’s natural demand for sleep is greatest. As one of his last official acts after nine years on the board, Goglia chaired the hearing. He noted with dismay that the accident occurred even though FedEx “is one of the more enlightened companies regarding the fatigue issue.”

Updating obsolescent flight time and duty time regulations has been on the NTSB “Most Wanted” list of aviation safety improvements since its inception in 1990. The FedEx crash case has focused attention on this issue, as it marks at least the third crash in which the safety board has cited pilot fatigue as a contributing factor. The two previous fatigue-related crashes were:

• The Aug. 18, 1993, crash of American International Airways Flight 808, a DC-8 cargo jet, at Guantanamo Bay, Cuba, at the end of a long day involving a last-minute runway change as in the case of the FedEx accident, and
• The June 1, 1999, crash of American Airlines [AMR] Flight 1420, an MD-82, at Little Rock, Ark., at the end of a long day involving a last-minute runway change, as in the case of the FedEx crash (see ASW, Oct. 29, 2001).

In addition, the May 1996 crash of a ValuJet DC-9 added impetus to the issue. As a result of its investigation into this event, the NTSB determined that fatigue and hours-of-work rules need to be extended to maintenance personnel (see ASW, May 12, 2003).

NTSB and Federal Aviation Administration (FAA) officials are scheduled to meet July 8 to see what can be done to break the long-standing gridlock over modernizing the flight and duty time regulations.

Richard Rodriguez, NTSB investigator in charge of the FedEx accident, described it as “a rushed approach over black hole conditions,” the risk of which was compounded by First Officer William Frye’s desire to use Tallahassee Regional Airport’s Runway 09 rather than Runway 27 in order to make a more straight-in approach to the airport. Frye was the pilot flying.

Although wind was negligible and Runway 27 featured an instrument landing system (ILS), PAPI (precision approach path indicator) lights, touchdown zone (TDZ) lights, approach lights and runway lights, Frye opted for Runway 09, which featured only PAPI lights to help the crew maintain a three-degree glide path on approach. That Capt. William Walsh did not override Frye’s decision was seen in retrospect as ill-advised, especially since Frye had not previously flown into Tallahassee.

The poor runway choice was one of the first indicators that both pilots were fatigued. We recall in this account some of the main points of the recent fatigue symposium held at the NTSB Academy (see ASW, March 22). People are not good judges of their own level of fatigue. This was a nighttime approach conducted at about 5:30 a.m., at a time of circadian low when the effects of a sleepless night can be the most pronounced. Capt. Walsh had not slept well the night before, and had been involved in a family crisis the day before – the emotional distress of having to euthanize a 14-year old beloved pet dog.

Frye had been on reserve status, involving alternating sleep-disrupting day/night shifts. He had not been expected to receive the call near the end of his reserve duty day to make the flight from Memphis to Tallahassee. Flight Engineer David Mendez had slept only briefly for about on hour before takeoff, having been awake since about 1:30 p.m. the day before. In short, all three pilots, each of whom had thousands of hours of flying experience, were suffering varying degrees of insufficient and off-cycle sleep at the time of the accident. The FedEx flight crewmembers fit most of the sleep-related factors in accidents laid out by researchers Mark Rosekind and David Dinges during the NTSB Academy symposium.

With the benefit of hindsight, the many fatigue-related factors in the FedEx crash are evident. In the cockpit discussion about which runway to use, Capt. Walsh gave all the right reasons for using Runway 27, but he acceded to Frye’s desire to descend and land on Runway 09, which had only the visual PAPI lights to guide the approach. Capt. Walsh’s evident passivity is symptomatic of fatigue, and recalls the degradation of attention of Capt. Richard Buschmann, who had been on duty for some 14 hours at the time of the Flight 1420 accident at Little Rock.

Not seeing red

What Walsh did not know was that his first officer was flying on a waiver for his color vision problem. Specifically, as was discovered in tests of his vision conducted after the accident, Frye had difficulty distinguishing red and green. To wit, red would appear to him more like a yellow to off-white.

Thus, he was unable to make proper use of the PAPI lights. If one is high on the glide slope, the four PAPI lights positioned alongside the runway will shine white. If too low, they will shine red. If on the glide slope, two lights will shine white, the other two red.

An indicator of Frye’s vision problem was his apology a minute before the crash, “I was lining up on that paper mill.” The paper mill featured flashing lights on its top structures, as is typical to warn aviators.

But then, when Frye belatedly lined up on Runway 09, the PAPI lights indicated he was too low for fully 40 seconds before the first impact with treetops. Nearly throughout the approach, engine power, as measured by engine pressure ratio (EPR), was too low.

When descending over dark terrain bereft of ground lights, as was the case here, the so-called “black hole” effect can seduce pilots into flying more of a concave approach than a straight three-degree glide path. In this situation, reliance on the PAPI lights was all the more important, yet Frye’s (Con’t on p. 4) ability to distinguish red from white was deficient. Yet Walsh and Mendez, both of whom had good color vision, and both of whom were looking ahead out of the cockpit and would have seen the red PAPI lights, said nothing. Such is the numb complacency that can attend fatigue.

Sound procedures not followed

FedEx requires pilots to be established on the runway centerline no later than four miles from the threshold. In this accident, Frye was not established on the centerline until just 2.5 miles from the threshold, at just 750 feet above the ground.

FedEx procedures also required pilots to be stabilized at 500 feet above the ground, which is to say they must have the correct power and a rate of descent no greater than 1,000 feet per minute. If these conditions are not met, a go-around is required.

In this accident, the airplane was well below the three-degree glideslope as it passed through 500 feet and the four PAPI lights were showing red. Yet as the airplane descended through 500 ft. at a descent rate of 1,300 feet per minute, Capt. Walsh called “stable,” one of the required call-outs in the landing procedure. NTSB investigators said he should have called “unstable” and commanded a go-around.

It was one of a pattern of errors he made throughout the descent. He had not responded to the low EPR, or to the excessive descent rate (similar to the way the Guantanamo Bay accident pilot had not responded to the stickshaker’s warning of imminent stall). Walsh had made a number of readback errors, similar to those made by Buschmann in the Flight 1420 accident – further indication of the insidious effect of fatigue.

Even though the airplane was coming in too low, on the verge of striking 60-foot treetops some 3,600 feet short of the runway, the airplane’s ground proximity warning system (GPWS) did not sound the alarm. When the airplane is configured for landing (e.g., flaps deployed and landing gear down), the GPWS is disabled. This is not the case with the enhanced GPWS technology.

Without GPWS, the last defense against disaster was breached.

The company had sound policies for stabilized approaches, yet they were not followed. That omission is another manifestation of fatigue – the tolerance for omissions and errors goes up. Both the captain and flight engineer had good color vision, yet they never said anything about the four red PAPI lights. Perhaps a subtle failing of the PAPI system is that until a pilot is on glideslope, he will be seeing those four red lights and the other pilot may be writing off that fact to the flying pilot “becoming established.” This is not the case with the T-VASIS system widely deployed in Australia. The poor choice of Runway 09, the failure to discontinue a poor approach – these are all subtle yet evident indications of the deteriorating of situational awareness accompanying fatigue.

Yet the company had a progressive “no questions asked” policy for fatigue. The policy in effect at FedEx is that pilots on a trip can call in fatigued at any time, and a sick day will be recorded.

NTSB vice chairman Mark Rosenker raised the question of “self-induced” fatigue, in that that pilots are responsible for managing their off-duty time to ensure that they show up for work rested for the job at hand. Brenner responded that the captain was under emotional duress, and the first officer was on an alternating reserve duty schedule, which complicated pre-flight personal rest management.

With respect to the “self induced” notion of fatigue, Goglia noted that FedEx “lets pilots off without retribution,” which accommodates this kind of human dilemma.

Nonetheless, the NTSB concern about fatigue remains, and the need to update regulations in light of the current state of knowledge about sleep. Member Carol Carmody noted, “Once again, fatigue is an issue,” recounting the previous accidents at Guantanamo Bay and Little Rock. With the FedEx crash, these accidents involve three airplanes written off as total losses and 11 deaths in the Little Rock case, when the airplane overran the runway and struck steel light poles, killing Capt. Buschmann and 10 passengers.

The NTSB’s David Ivey, a former airline pilot and chairman of the operations group for the FedEx investigation, said, “The requirement to be stabilized at four nautical miles is to give the pilots plenty of time” to make a safe approach. Had the crew complied with procedures, a safe landing could be made. The accident, Ivey said, “was a flight crew error.”

“I would not elevate fatigue beyond that of a contributing factor,” he said. Yet, as was discussed in the NTSB Academy fatigue symposium earlier this year, degraded judgement, deficient crew coordination and deviation from proven procedures often are symptoms of the insidious effects of fatigue. As Brenner said, “The captain provided all the right reasons not to use Runway 09, and yet he acceded to it.”

First Officer Frye’s waiver for color vision was a point of major concern to the NTSB. John Clark, head of NTSB aviation accidents, said, “This person had a significant [color vision] deficiency that was not uncovered until after the accident.”

Frye failed seven of eight color-vision tests he was administered after the Tallahassee accident.

NTSB officials estimated that hundreds of pilots receive color vision waivers annually. These waivers, Goglia said, are based on an earlier generation of cockpit instruments featuring black and white dials where the ability to distinguish between colors was not important.

However, with glass cockpit displays capable of generating a rainbow of colors, the ability to distinguish between them can be critical for situational awareness.

For example, weather radar displays will show the severity of convective weather (thunderstorms) in a pattern of red and yellow colors, with red marking the most severe storm activity. Similarly, for enhanced GPWS displays, yellow and red are used to map dangerous terrain ahead of the airplane’s flight path.

A pilot unable to distinguish between red and yellow, Goglia said, “can proceed into danger.” In other words, the cockpit instruments may be sending the correct messages, but a color-deficient pilot won’t receive them. Color blindness can cripple the man-machine interface.

For these reasons, the NTSB called upon the FAA to research the effectiveness of current color vision tests, and to implement a standard battery of tests so that pilots with impaired color-related vision are not “certificated without limitations.”

Two footnotes to the FedEx case bear mention. The three pilots are still employed but remain in a non-flying status. As for procedures, FedEx now requires enhanced GPWS to provide an improved final margin of safety for operations into airports with closed control towers, as was the case at the time of the Tallahassee crash.