ATR 42 accident at San Juan, Puerto Rico, 9 May 2004

Accident narrative

On May 9, 2004, about 1450 Atlantic standard time, Executive Airlines (doing business as American Eagle) Flight 5401, an Avions de Transport Regional 72-212, skipped once, bounced hard twice, and crashed during landing at Luis Muñoz Marin International Airport in San Juan, Puerto Rico. The airplane came to a complete stop on a grassy area about 217 feet left of the runway 8 centerline and 4,317 feet beyond the runway threshold. The captain was seriously injured. The first officer, two flight attendants, and 16 of the 22 passengers received minor injuries, while the remaining six passengers were uninjured. The airplane was substantially damaged.

### The flight

Flight 5401 was a scheduled passenger flight from Eugenio Mariá de Hostos Airport in Mayagüez, Puerto Rico. The captain was the nonflying pilot and had accumulated 6,071 total flight hours, including 3,814 hours in the company’s ATR-42 and -72 airplanes. The first officer was the flying pilot. He had 2,000 total flight hours, with about 20 hours in the ATR-72. This was the first officer’s first scheduled flight since completing his initial operating experience.

### The sequence of events

The flight departed Mayagüez about 1415. Approaching the San Juan traffic area, the crew received weather information reporting winds from 060 degrees at 17 knots, gusting to 23 knots. The captain briefed a minimum approach airspeed (Vref) of 95 knots and told the first officer to "stand by for winds." The first officer set his airspeed bug to 95 knots.

At 1443:03, an approach controller cautioned the pilots about possible wake turbulence from a preceding Boeing 727. The captain instructed the first officer to get his speed back, eventually telling him to "just go about one forty."

The flight was cleared to land on runway 8. During the approach, the captain warned the first officer, "you better keep that nose down or get some power up because you're gonna balloon," and told him to bring the power back. As the ground proximity warning system alerted "minimums," the captain instructed the first officer to get the airplane's nose up. Shortly after, the captain told him to "power in a little bit."

Flight data recorder (FDR) data indicated the airplane crossed the runway threshold at 110 knots indicated airspeed. After crossing the threshold, the captain again told the first officer to power in a little bit and not to pull the nose up, stating, "you're ballooning."

The airplane touched down for the first time about 1449:41, about 1,600 feet beyond the runway threshold, and skipped to an altitude of about 4 feet. The captain stated "my aircraft" and took control.

The airplane touched down a second time about 1449:45, about 2,200 feet beyond the threshold. It then pitched up to an angle of 9 degrees, climbed to an altitude of 37 feet, and engine torque increased to 43 percent before decreasing.

The airplane touched down a third time about 1449:51 in a 7-degree left bank, about 3,300 feet beyond the threshold. The FDR recorded a vertical load of about 5 Gs. The airplane bounced to an altitude of about 24 feet.

About 15 seconds after the initial touchdown, the airplane touched down a fourth time about 4,000 feet beyond the threshold. The airplane banked 29 degrees left wing down and slid to a complete stop.

### What the investigation found

The Board found that the flight crew did not account for winds when calculating the minimum approach airspeed, failing to comply with company procedures. Based on the reported winds, the correct Vref for the flight should have been 101 knots. The airplane crossed the threshold at 110 knots, almost 15 knots faster than the 96 knots set on both pilots' airspeed indicators. The Board also found that the captain did not properly follow before-landing procedures, as the power management selector was left in the climb position rather than the takeoff position.

The investigation determined that the winds were within the airplane's performance capabilities and that wake turbulence from the preceding 727 was not a factor.

The Board concluded that the flight crew could have completed a successful landing after the initial touchdown. However, after taking control, the captain made abrupt changes in pitch and power. The Board concluded that the captain demonstrated poor cockpit oversight and piloting techniques, and that after each bounce, he did not make appropriate pitch and power corrections or execute a go-around.

Executive Airlines did not provide formalized bounced landing recovery techniques to its pilots before the accident. The Board concluded that written company guidance would have increased the possibility that the captain could have recovered from the bounced landings or executed a go-around.

During the third touchdown, the vertical forces on the left main landing gear exceeded the forces the gear was designed to withstand, resulting in an overload failure. The left gear fractured at its vertical trunnion leg. The pitch control uncoupling mechanism also uncoupled during this touchdown; the Board concluded this uncoupling would not have prevented the flight crew from controlling or safely landing the airplane.

The captain's cockpit seat failed during the accident sequence. Metallurgical examination revealed preexisting weld discontinuities on the seat's sleeve assembly. The Board concluded the seat failed when it was subjected to vertical loads that exceeded certification requirements.

The investigation revealed that the first officer had a history of treatment for anxiety and had been prescribed alprazolam, which he failed to report on his Federal Aviation Administration medical certificate applications. Postaccident drug testing was negative. The Board concluded that not enough evidence was available to determine whether or to what extent the first officer's medical condition and prescription drug use contributed to the accident.

Finally, the Board found that the FDR's left aileron surface position data was invalid. The airplane was equipped with string potentiometer sensors that had a high failure rate. The Board concluded these sensors were unreliable and noted that more frequent FDR functional checks could ensure timely identification of malfunctions.

### Probable cause

The National Transportation Safety Board determines that the probable cause of this accident was the captain's failure to execute proper techniques to recover from the bounced landings and his subsequent failure to execute a go-around.