In An Emergency, Trust But Verify, Part 1

NTSB photo

Transair Boeing 737-275C freighter

Credit: NTSB

It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so. (Attributed to Mark Twain)

A Boeing 737-275C freighter was departing Daniel K. Inouye International Airport (HNL) at 0134 Hawaii-Aleutian standard time on July 2, 2021, when the crew heard a “pop” passing through 400 ft. The two pilots knew something was wrong almost immediately.

The airplane yawed to the right, and the first officer (FO), who was the pilot flying, initially thought the right engine had failed. Four minutes after the initial failure, he changed his mind. He spoke with a tone of certainty when he said it was the left engine that failed, and the captain took his word for it.

What the FO thought just wasn’t so. The left engine was running fine but was reduced to idle thrust. During the next 12 minutes before the airplane splashed down in the Pacific, neither pilot made any attempt to advance the left throttle, even after it became apparent the freighter would continue to descend into the water.

Why did the pilots just tune out the left engine? What happened during that four minutes after the right engine failed to change their minds? NTSB investigators sought to find out.

The accident airplane was one of five aging Boeing 737-200s operated by Rhoades Aviation, a Part 121 all-cargo airline based in Honolulu. The company had a business name—Transair—painted on the fuselage. Of the company’s 230 employees, 24 were pilots.

The two pilots involved in the accident reported for duty at midnight on July 1, about 15 minutes early. They performed their preflight duties and the FO obtained the ATC clearance. They were cleared to the Kahului Airport on Maui with an initial heading of 155 deg. and an initial altitude of 5,000 ft.

All seven pallet positions were loaded with cargo and the 737 had 14,000 lb. of fuel aboard. The crew commenced a taxi to Runway 8R at 0123. At 0132, Honolulu Tower cleared them for takeoff. The FO was the pilot flying. As they rolled down the runway, the captain called “vee one,” then “rotate,” then “vee two,” then “positive rate.” At 0133:46 the FO called “gear up.”

Up to this point, the crew had performed their crew coordination perfectly, exactly by the book. They used the right verbiage for the change of controls and made all the right callouts. Six seconds later, that coordination would be severely challenged.

The cockpit voice recorder (CVR) recorded the sound of a “thud” and a low frequency vibration tone. The FO said “oh!” and the captain said “lost (an) engine, you got it?” The FO continued to control the airplane and the captain said, “ lost number.” The FO replied, “number two…yep.” The captain agreed. They were channeling each other’s thoughts. They both thought the right engine had failed.

During the FO’s takeoff brief, he had described the plan for an engine out emergency after V1 “if we lose the engine at vee one we'll climb straight out to five hundred feet, one point three DME, whichever comes first, we’ll start a right turn to two twenty up to eight hundred, we'll level off, we’ll accelerate, we’ll clean up, we’ll coordinate ATC, run the checklists as appropriate.”

Out of 500 ft., the captain called out “five hundred eight hundred,” prompted the turn to 220 deg., and raised the flaps. Then he tried, at first unsuccessfully, to get the attention of the tower. Twice he told the tower he had an emergency and was turning to a 220 heading, and twice the tower gave him a routine clearance without acknowledging the emergency. The captain spent almost a minute and a half trying to get the tower’s attention. 

While the captain was focused on the radio, the FO tried to level the airplane at 2,000 ft. but allowed the airplane to accelerate to 252 kts. To correct, he pulled both thrust levers back together “in unison.” The flight data recorder (FDR) showed that he continued to retard the left engine, but not the right. That thrust reduction began to take place at 0135:18, about one minute before the captain was able to return his attention to the engine instruments. By the time the captain looked at the EPR (engine pressure ratio) gages, the left engine was at idle, 1.05 EPR, and the right engine was at 1.12 EPR. 

Finally, the tower said, “Rhoades express eight ten you are cleared visual approach runway four right, you can turn in toward the airport.” It was 0136.

The captain did not turn back. Instead, he decided to take control of the airplane and have the FO “set things up.” Shortly thereafter, he was interrupted again, this time by company dispatch: “eight ten uhh dispatch uhh...let me know what’s going on.”

The captain ignored the radio call and said to the FO, “read the gauges and see which one...who one...which...who has the EGT (exhaust gas temperature)?”

The left engine EPR was lower than the right.

The FO replied, “yep so it looks like the number one.”

“Number one is gone?” the captain asked.

“It’s gone yep. So, we have number two.” 

The captain confirmed, “so we have number two, okay.”

From this point on, the crew’s confusion became ever greater. The captain called for the “engine failure shutdown checklist” but didn’t specify which engine should be shut down. He took control of the radios but confused the controller by saying he could turn toward the airport but wasn’t ready to land. The controller issued a 250 deg. heading. It was 0138:53 and they were still headed away from the airport.

The captain pushed the right thrust lever up to 1.22 EPR, and the FO pointed out the right engine was running hot. “We’re red line here,” he said, and “we should pull the right [thrust lever] back a little bit.” He did not run the checklist. 

The airplane was sinking and slowing. The captain had lost sight of the airport and asked the controller for vectors back to the airport. “We might lose the other engine too,” he said. As the airplane descended through 1,050 ft., the airspeed was 157 kts. and the stick shaker sounded briefly. Sounding bewildered, the captain said, “what’s this?” followed by “we can’t keep going down.”  The right engine EGT was “beyond max.”

An electric voice sounded, “five hundred.” The captain began a rather long radio transmission, asking for fire trucks to be ready and the Coast Guard to be notified. The FO pleaded with him, “just fly the airplane!” The captain continued to talk with the tower as the airplane descended, even asking for a heading to another airport—Kalaeloa (JRF). That airport was off to his left 3 mi., but he was well below 300 ft. by this time.

The EGPWS (enhanced ground proximity warning system) began sounding, “terrain, terrain,” and “pull up, pull up.” The CVR recorded the sounds of impact at 0145:17.

Pilots Recovered From Sinking 737

NTSB photo
The wreckage of the Transair 737 came to rest on the ocean floor. Credit: NTSB

The airplane struck the water hard and came to a quick stop. The FO’s seatback failed and he struck the top of his head on an object. Both he and the captain opened their side windows and escaped as ocean water flowed into the cockpit. The FO clung to the nose section, then spotted a large wooden pallet afloat and moved to it.

The captain swam along the left side of the airplane, finally grabbing the tail section. Ocean waves knocked him off the tail several times.

A Coast Guard rescue helicopter shined a spotlight on the FO, who pointed to the captain. The helicopter flew to the tail section, and a rescue swimmer descended and secured the captain. After they were hoisted up to the helicopter, the swimmer re-entered the water to assist the FO. He helped the rescue vessel pick the FO out of the water.

The NTSB responds to the accident site, in Part 2 of this article.

Roger Cox

A former military, corporate and airline pilot, Roger Cox was also a senior investigator at the NTSB. He writes about aviation safety issues.