United dive after Maui departure adds to list of industry close calls

The previously unreported December incident saw the Boeing 777 come within 800 feet of the Pacific Ocean.

Release Date
February 12, 2023
United dive after Maui departure adds to list of industry close calls
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A United Airlines Boeing 777-200 came within around 800 feet of impacting the Pacific Ocean off the north coast of Maui shortly after takeoff on December 18. The occurrence, not previously reported, adds to a series of extremely serious safety incidents and major operational disruptions within the U.S. aviation system in recent weeks.

Flight 1722 from Maui to San Francisco left Kahului Airport at 2:49 PM Hawaiian time in stormy weather and initially appeared to climb normally. Granular data analyzed with Flightradar24 showed the aircraft reached roughly 2,200 feet before beginning a steep dive that, according to the tracking telemetry, reached a descent rate of nearly 8,600 feet per minute. 

The aircraft quickly recovered, but not before descending below 775 feet. Two people familiar with the incident said the climb produced forces of nearly 2.7 times the force of gravity on the aircraft and its occupants as that steep descent transitioned to an 8,600 foot per minute climb. The entire incident appears to have stretched no more than 45 seconds and in between radio calls with air traffic controllers in Maui, according to LiveATC recordings reviewed by The Air Current.

The aircraft subsequently climbed to 33,000 feet and landed in California 27 minutes early after the 4-hour and 15-minute Pacific crossing. The Boeing widebody configured with 364 seats was quickly turned around at SFO and departed to Chicago on its next flight about two and a half hours later.

Weather information available at the time of departure showed heavy rain at the time of takeoff and that clouds were broken above 900 feet and overcast at 2,000 feet. A flash flood warning had been issued that afternoon for Maui County.

It is not clear if the abrupt dive and recovery of the flight was noticed by air traffic controllers in Maui, but the ATC recordings reviewed by TAC did not include any exchange about the incident. Moments after the aircraft had recovered to roughly 3,000 feet, the controller cleared the 777 to proceed to waypoint EBBER, a navigation intersection 190 miles east of Maui.

One senior aviation safety official said such an extreme dive would normally prompt a call to the aircraft to ensure there was no threat of hijacking or continuing issues maintaining control of the aircraft.

The incident, which appears to have escaped any commentary on social media, came the same day 25 people were injured, six seriously, aboard a Hawaiian Airlines flight from Phoenix to Honolulu during severe turbulence in the vicinity of Maui. That same Pacific storm spawned a massive ice storm that stretched across the western and central U.S. in the days that followed, triggering the Christmas meltdown at Southwest Airlines.

Related: Southwest Airlines and the anatomy of an IT meltdown

Safety incidents are not uncommon within airlines, though severe or catastrophic outcomes are. The major U.S. airlines all have a voluntary and confidential self-reporting structure for incidents. There are thousands of reports filed each year across airlines like United, but the system is designed to capture and learn from each one without focusing blame on individuals. These systems, which prioritize mitigating the risk of recurrence and emphasize training, are a major reason why the U.S. aviation industry has the track record of safety that it does.

A spokesman for United confirmed the incident and said after landing at SFO, a formal internal safety report was filed by the pilots and the aircraft was inspected before its next flight. “​​United then closely coordinated with the FAA and ALPA on an investigation that ultimately resulted in the pilots receiving additional training. Safety remains our highest priority,” the spokesman said. After publication United told TAC that the incident was not related to any fault with the aircraft.

The FAA in a statement said the United flight crew reported the incident to the FAA as part of its voluntary safety reporting program. A spokesman said, “The agency reviewed the incident and took appropriate action” without elaborating.

The United spokesman added that the pilots “fully cooperated with the investigation and their training program is ongoing.” The pilots involved had a combined 25,000 hours of total flying time, but the airline declined to say which crew member was flying at the time and how much of that experience was on the 777 for each member of the flight crew.

United said it did not report the incident to the National Transportation Safety Board. The airline considered the incident to not rise to the reporting criteria of the NTSB, which typically is necessitated by either damage to the aircraft or injuries sustained by passengers, crew or others on the ground. Neither was the case. The airline declined to say if the flight data recorder or cockpit voice recorder were analyzed after the flight, though the CVR would’ve been overwritten by the two-hour recording duration. 

The incident preceded a similar close call by a crew of a Qatar Airways Boeing 787-8 on January 10. That aircraft departed out of Doha and the crew reportedly lost situational awareness upon climb out, inadvertently entering a 3,000 foot per minute descent in a turn before recovering 800 feet above the water. That flight continued on to its destination in Copenhagen.

The NTSB has two active investigations into additional serious safety incidents on major U.S. airlines. The first is a January 13 runway incursion at John F. Kennedy International Airport that brought a departing Delta Air Lines 737-900ER and American Airlines 777-300ER within 1,400 feet of one another as American’s twin-aisle jet crossed the active runway.

The second incident on February 4 involved a FedEx 767-300 freighter that overflew a Southwest 737-700 rolling down the runway at Austin Bergstrom International Airport. The FedEx flight aborted its landing, but came within less than 100 feet of the Southwest flight, according to NTSB Chair Jennifer Homendy.

Related: Emirates 777 close call in Dubai returns spotlight to automation over-reliance

The New York and Austin incidents, just as in Maui, will provide no voice recorder data for the inquiries because of the limited capabilities of the voice recorders. Similarly, in the case of an Emirates flight that nearly crashed into a neighborhood in Dubai in December 2021, the flight continued on to Washington, D.C. overwriting any voice recording for an inquiry. This remains a recurring concern of the NTSB, which has long advocated for a 25-hour recording capability.

Warnings from a fragile system

The spate of recent incidents highlights both the redundant safety measures built into commercial aviation and the possibility for catastrophic accidents in spite of them. On the one hand, each incident had a positive outcome. No one was hurt, nor was there any damage caused. Two safety experts pointed to the aggregate safety of the system and the lack of direct commonality between each discrete incident, the airlines and their circumstances.

However, the two runway incursion events, each separated by three weeks and punctuated by a major airline operational meltdown and an FAA system failure have been seen by aviation safety watchdogs as a series of warnings about the fragile state of the U.S. airline industry, which over the past three years has been obliterated and reassembled through a global pandemic. The airlines, which were forced to cut operations in the spring of 2020 by more than 95% from their 2019 peak, tried to conserve cash, shed payrolls and retire entire fleets of aircraft to survive.

Related: The last leg of the U.S. airline recovery is going to be the hardest

Now, Boeing and Airbus are trying to get new airplanes into the hands of their customers as quickly as possible as the COVID-19 pandemic wanes and demand for leisure and business air travel accelerates back toward 2019 levels. Airlines and aircraft manufacturers are all hiring tens of thousands of staff to assist in the recovery, but the operational and industrial chains that ensure U.S. aviation runs smoothly remain fragile at best.

Although specific provisions within the CARES Act allowed for airline payrolls to be preserved through the pandemic, airlines have also faced challenges in compensating for the mass retirement of senior pilots during the pandemic, which has necessitated significant retraining of pilots who moved up the seniority ladder to new aircraft and the corresponding influx of regional pilots who transitioned into mainline operations.

Elan Head also contributed to this article.

Write to Jon Ostrower at jon@theaircurrent.com

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