A United 777’s terrifying takeoff from Maui
First let’s go over the background of the incident. On December 18, 2022, United Airlines flight UA1722 was scheduled to operate from Maui (OGG) to San Francisco (SFO) with a 22-year-old Boeing 777-200 that had the registration code N212UA.
The plane took off at 2:49PM and climbed to 2,100 feet. At that point the plane began a steep dive, descending at nearly 8,600 feet per minute, which would have produced forces of nearly 2.7x the force of gravity. The plane descended down to 748 feet above sea level.
Fortunately at that point the pilots recovered the aircraft, and the flight continued to San Francisco without further issues. There were no injuries, and no damage to the aircraft. It can’t be overstated just how close of a call this was. At a descent rate of 8,600 feet per minute and an altitude of 775 feet, the plane was seconds from catastrophe.
What caused this United 777 incident?
How could two pilots nearly crash a 777 into the ocean when visibility was good? The NTSB has just released its final report about this incident, so now we know what caused this incident.
The first thing to note is that the pilots were pretty experienced, with the captain being a lot more experienced than the first officer on this aircraft. The captain had a total of 19,600 flight hours (including 5,000 hours on the 777), while the first officer had 5,300 flight hours (including 120 hours on the 777). So around 25,000 hours of experience in the cockpit is quite a bit, though the first officer was basically brand new on the 777.
What’s the cause of this incident? Well, it boils down to a miscommunication between the captain and first officer, and a failure to recover quickly from that miscommunication. Here’s what the NTSB’s investigation revealed:
The captain and first officer had agreed to take off with flaps set at 20 degrees, based on performance calculations
The captain was the one flying this segment, and while the initial climb out was normal, the flight crew noticed airspeed fluctuations due to wind shear, so the captain called for the flaps to be reduced to five degrees
The first officer thought he heard the captain say 15 degrees, rather than five degrees, so that’s what the first officer set the flaps to (the pilot not flying is the one who sets flaps)
The captain noticed the plane wasn’t responding the way he expected, and that the airspeed was accelerating rapidly
Therefore the captain reduced the engine thrust manually, to avoid flying too fast with flaps
He again called for the flaps to be moved to five degrees, and at this point the first officer moved the flaps to five degrees
The first officer “knew the captain was having difficulty with airspeed control,” and asked the captain if maybe his instruments were wrong, but he didn’t receive an immediate response
Both pilots remembered feeling the airplane’s pitch decreasing, and the airspeed increasing
The captain then called for flaps to be set to one degree
Alarms were going off in the cockpit, including the ground proximity warning system going off
The captain pulled up on the control column, which is the point at which the plane was at 748 feet, and began its recovery
“The flight crew’s failure to manage the airplane’s vertical flightpath, airspeed, and pitch attitude following a miscommunication about the captain’s desired flap setting during the initial climb.”
My take on this United 777 incident
Aviation is incredibly safe, despite how much goes into it, and how many human factors there are. Along those lines, it’s wild how a simple miscommunication of a single number nearly caused a catastrophic incident. With that in mind, a few thoughts:
It’s hard to put the blame on one specific pilot here; the first officer misunderstood the captain, and the captain was the one flying the plane
Typically if there’s a small miscommunication, there’s plenty of time to recover, though takeoff is such a critical phase of flight, so a small error can have big implications
I think what’s perhaps most alarming here is how this incident was never reported to the NTSB voluntarily by United, but rather it wasn’t until this got media coverage a couple of months later that United finally opened an investigation
Honestly, this flight was within seconds of having a very different ending, so thank goodness the pilots at least recovered the way they did
Bottom line
The NTSB has released its final report about a scary incident that happened in late 2022, when a United Airlines Boeing 777 was departing Maui. During the climb out, the aircraft accidentally descended all the way to 748 feet.
The cause of the incident was determined to be a miscommunication between the two pilots over the flap settings. The captain asked for flaps to be set to five degrees, though the first officer thought he said 15 degrees. On top of that, the NTSB blames the pilots’ failure to manage the aircraft following a miscommunication.