Date: 202008
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Situational Awareness; Distraction; Confusion
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Attendant
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Environment - Non Weather Related; Company Policy
Primary problem: Human Factors

Narrative: 100 NM prior to TOD; FO called FAs requesting a Lav break. Lead FA (Purser) stated that none of the FAs were comfortable coming up to the Cockpit unless the remaining pilot (in the cockpit) wore a face covering. As he really needed to use the Lav; the FO consented to the FA's request and then told me (the Captain) of the FA's request. This is the first time in my XX+ years at airline and XY+ years as a Captain; that I've had a FA hold me hostage to get a Lav break. The FA requested that the pilot remaining in the cockpit wear a face covering in the cockpit while the other pilot was absent from the cockpit on the Lav break. I never wear a face covering in the cockpit; while flying the aircraft; especially with the other pilot absent from the cockpit.If it's not already obvious; let me restate that the FARs prohibit the use of a face covering (or the wearing of a beard) that would prevent a proper seal of the O2 mask. At FL400 and a TUC (Time of Useful Consciousness) of 15 seconds; with the other pilot absent from the cockpit; is NOT the time to find out that your O2 mask doesn't work with a face covering. As the FO left the cockpit; and me wearing a face covering; per the FA's request; ATC gave us a vector off course and a speed reduction for traffic. I replied to ATC; but they couldn't hear my boom mike through the face covering. At FL400; with the other pilot absent from the cockpit; is NOT the time to find out ATC can't hear your boom mike through the face covering. Before she left; I told the Lead FA that I would be writing a report and she said something through her face covering that I couldn't hear. At FL400; with the other pilot absent from the cockpit; is NOT the time to be unable to communicate with the only other person in the cockpit.Face coverings are UN-SAFE while taxing; flying; or maneuvering the airplane. They fog up my glasses which I am required to wear; they prevent me from communicating clearly with ATC; the other pilot or with the FA when the other pilot is absent from the cockpit.After the flight; we had a long debrief with the FAs. Company COVID-19 face covering information DOES NOT address the wearing of a face covering while operating an aircraft. The FAs on this flight; believed I was operating the aircraft in disregard of the Federal Aviation Regulations and in direct violation of Company Policy. It was unclear to these FAs; who gets to tell who must wear a face covering while operating an aircraft. None of these FAs seemed to understand who the Pilot-In-Command (PIC) is when operating an aircraft.In the masked de-brief; they were argumentative and confrontational. They thought that the remaining pilot on the cockpit was required to wear an O2 mask anytime the other pilot is absent the cockpit. It is very difficult to discuss face coverings with a FA who's been told that everyone is required to wear a face covering at all times while on an aircraft or on company property. The FAs do not understand the problems caused by face coverings in the cockpit (the O2 mask; Pilot to Pilot or Pilot to ATC communications issues; or Eye Glass fogging). The FAs believe that they can tell the Captain how to operate an aircraft in direct violation of the FARs; safety procedures and common sense. This has to stop. The Company must tell all employees; but especially FAs; that the Captain is in command; that face coverings cause safety issues in the cockpit and that pilots are NOT required (in fact; are discouraged from wearing) face coverings while operating an aircraft.




Synopsis: Air carrier Captain reported that the flight attendants were not comfortable coming into the flight deck while the pilot was on a restroom break; until the remaining pilot was wearing a face mask. Reporter described safety concerns with having to wear a face mask in the cockpit.