Date: 202007
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Light: Night
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Turbine Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Weather
Primary problem: Weather

Narrative: Our flight was being vectored to go around convective activity. We were at FL410 going around weather and trying to avoid all thunderstorms. We experienced #1 engine was not producing full power and had to descend to FL380. The static noise was so loud we could not hear ATC. We needed to descend to a lower altitude and went down to FL380. I instructed my First Officer to call ATC on #2 COMM; at that time I took control of the aircraft. We descended to FL380 and were able to talk to ATC. We came out of the weather and the #1 engine was operating normally. We continued with no problems.


Second narrative: While navigating through a weather front with convective activity; aircraft performance degraded due to static air temperature (SAT) change. Flight was planned and initially flown at FL410. While in the middle of frontal passage the SAT increased significantly (-27 at FL380) and FMC Max altitude indications decreased to FL380 with a .73 Max Mach indication. I informed the Captain of this change on several occasions and also asked if he wanted to descend. The aircraft stayed at FL410 until we could hear and see indications of both engines beginning to roll back. At that point I twisted the altitude bug on the MCP to FL380 and stated to the Captain 'descend now'. He initially twisted the altitude select knob back to FL397 and asked me to talk with ATC. I immediately said 'I will get to them when I can; we just need to descend ASAP.' Due to the convective activity; radio static made it impossible to talk with Center anyway. Both start switches were in FLT and both engines stabilized with normal indications fairly quickly after initiating the descent. Communications were re-established with ATC somewhere between FL390-FL400 on VHF.This was my leg to fly. My plan was to deviate significantly around the weather; which would have added approximately 10 minutes to our total fight time. Captain wanted to fly through the front; so at his request he became the Pilot Flying until we stabilized on the other side of this weather. It was clear I was uncomfortable with this decision to navigate through the storm. I should have been more adamant about navigating around this weather and not let him continue flying above our Max operating altitude instead of simply briefing him of our performance limitations.


Synopsis: B737 flight crew reported descending to a lower altitude after experiencing a power loss at FL410 while penetrating weather.