The company’s two-communication rule in the FOM
Footnote 163 authorized the FO to assume control of the aircraft and fly it to a safe situation in the event that the pilot flying (PF) became obviously or subtly incapacitated. The captain of FAB6560 was verbally responsive to the FO’s comments and suggestions, and was making control inputs. Therefore, the captain was not obviously incapacitated. However, his persistence in following his course of action despite the FO’s verbal advisories indicates that he was experiencing subtle incapacitation, which was likely due to the stress associated with the deteriorating approach parameters and associated workload.
It is likely that the FO did not recognize the captain’s behaviour as that of subtle incapacitation. If the FO considered the two-communication rule, it is likely that he concluded that the captain was not incapacitated and the rule did not apply.
The FO’s non-application of the two-communication rule highlights a deficiency in the rule, in that the rule relies on the judgment of the PNF to determine whether subtle incapacitation exists. Recognition of subtle incapacitation may take considerable time, and it may not occur at all. Outside of the two-communication rule, there was no guidance provided to address a situation in which the PF is responsive but is not changing an unsafe course of action. This situation presented a unique problem for the FO of FAB6560; that is, how far should he allow the aircraft to deviate before taking over control from the captain?
There is a history of incidents and accidents in which the FO was the PNF and warned of a deteriorating situation, but did not take control when the captain continued an unsafe course of action (section 1.17.8.5). In all of these occurrences, the company had some form of two-communication rule, but the defence failed because the FO did not intervene and take control of the aircraft. Some likely reasons for this failure are difficulty in identifying subtle incapacitation, ambiguity in the wording of the procedure, or inhibitions on the part of FOs to take the drastic measure of taking control from a captain.
At the time of the First Air accident, there was no training or guidance within the company on how an FO would escalate a concern to the point that a go-around or change of control could be commanded. In the absence of policies and procedures, such as PACE (probing, alerting, challenging, and emergency warning), enabling the FO to escalate his concern as well as providing the authority to take control of the aircraft from the captain, the FO was limited to an advisory role. The FO was clearly aware of the increasing risk. The approach had continued beyond 2 points at which a go-around was required: first, when there is full localizer deflection, and second, in an unstable approach below 1000 feet. At both of these points, the FO attempted to communicate the need to go around to the captain. While not as definitively and clearly expressed as they could have been, these attempts are indicators that the FO was continuing his efforts to change the captain’s course of action.
The FO had previously flown as captain on another aircraft type with the company. However, he was new to the B737, and although obviously uncomfortable with the navigational situation, deferred to the captain.
There was no policy specifically authorizing an FO to escalate his role from advisory to taking control, and this FO likely felt inhibited from doing so. The FO made many attempts to communicate his concerns and suggest a go-around, but did not take control of the aircraft from the captain.
This accident and the other 3 occurrences cited (section 1.17.8.5) are indicators that failure of FOs to take control in deteriorating situations will occasionally result in catastrophic consequences in the global fleet of transport aircraft. Without policies and procedures clearly authorizing escalation of intervention to the point of taking aircraft control, some FOs may feel inhibited from doing so.