Corporate G650 flight crew reported fatigue and an inadvertent vertical speed climb selection contributed to an altitude deviation in a holding pattern.

ACN 2059378 2023-11 Gulfstream G650 Commuter and Corporate Flight Crew Fatigue Reports

DescentPart 91

What is ASRS?

The Aviation Safety Reporting System is NASA's voluntary, confidential, non- punitive incident-reporting system, established 1976. Pilots, controllers, dispatchers, and maintenance technicians file reports describing safety- relevant events. NASA de-identifies every report before adding it to the public database. Reports are not investigated by NASA, the FAA, or the NTSB — they represent the reporter's perspective.

Pilot narratives

Verbatim from the de-identified NASA record. First-person account by the reporter. NASA strips identifying details (names, company, specific time); anonymization placeholders are ZZZ, X, Y.

Reporter 1

I was the relief pilot and was sitting on the jumpseat as we approached. In a holding pattern at 16,000 ft, we were given a descent to 12,000 ft. PNF entered the altitude in the alt select box and it was verified by PF (Pilot Flying). PF selected vertical speed to descend, but inadvertently dialed the v/s knob to a climb. PNF noticed immediately and notified the PF. A reversal was made to correct. ATC advised they would be filing a report. I was unable to see the v/s select due to the PF's hand hovering over it. It happened so quickly that from my vantage point on the jumpseat I did not immediately notice the climb. All 3 pilots were fatigued due to the long flight, time of the flight and jet lag from previous days of flying. We had also experienced a couple of wake turbulence events from a B737 MAX 7 miles ahead of us that was a definite distraction.

Reporter 2

While in the holding pattern an altitude deviation of 300 ft. was immediately corrected. Caused by wake turbulence, fatigue.

Reporter 3

We were inbound to Dubai (OMDB). We were assigned direct to VUTEB intersection, hold as published, maintain FL160. We entered the hold at FL160. After completing about half of the first pattern, we were assigned a descent down to 12,000 ft. I acknowledged the call and rolled in the new altitude into the preselect. I got busy with another task, and when I glanced back up at the flight guidance panel, my co-captain had selected vertical speed, "UP" 1,500 FPM, instead of down. I called out we were climbing instead of descending. By the time the PF (Pilot Flying) made a correction, we had climbed to 16,500 ft. The ATC controller called us out for the deviation. We acknowledged the error and stated we were descending to our assigned altitude. We were pretty fatigued at this point and operating at night in a busy traffic environment. We should have called out the mode we were using to descend the airplane and by how much down we were planning to use. We both would have caught the error right away.

NASA classification — Anomalies

Deviation - Altitude
Deviation / Discrepancy - Procedural
Inflight Event / Encounter

NASA classification — Assessments

Contributing Factors / Situations: Environment - Non Weather Related · Human Factors · Procedure
Primary Problem: Human Factors

ASRS reports are voluntarily submitted, de-identified by NASA, and represent the reporter's perspective. The presence of reports on a topic cannot be used to infer prevalence in the National Airspace System. The authoritative source is the NASA ASRS Database Online at asrs.arc.nasa.gov ↗.