Henry, re # 28, I agree with the need for clear and concise communication, but the object of communication in SOPs is to achieve understanding, and thence correct action; this is the aspect which I question.
Do we really understand what some procedures mean, how they should be interpreted, how executed. None of this is self evident in many of the posts above.
My question on Amber warnings was partly rhetorical. The problem as I see it is not an agreement or disagreement with the manufacturer’s advice; it is whether we understand the advice (why, when, how).
We cannot hide behind manufacturers’ recommendations or some system logic, particularly if ambiguous or not applicable to a specific situation.
The need for understanding does not ignore manufacturers’ procedures, but if not already apparent, operators must seek or add clarification. As examples:-
‘Engine Failure or Fire’ might reduce opportunity for error in identifying ‘severe damage’ vs ‘other’ damage (#31). This, together with explanatory (training) text defining an engine failure, e.g. more than 2% drop of N1 (power parameter)
and associated indications on N2/EGT, could eliminate the need for interpreting or even requiring an entry for ‘sudden loss of power’. Additionally this could provide some differentiation between an engine failure and a transient engine surge when the combination of indications might not be observed, although both events could be associated with a distracting loud bang – as could a tyre burst.
IIRC the original context of unsafe or unable to fly came from the
“Industry/FAA Takeoff Safety Training Aid”; this refers to decisions
after V1 (paras 2.3.1.2. & 2.3.6.10.). The point apparently missed by the ‘brevity’ of the SOPs quoted in this thread and also by the manufacturers (which is surprising because they drafted the training aid).
There is similar guidance in
”Revisiting the Stop Go Decision” (Takeoff and Departure Operations), which introduces ‘doubt’ that the aircraft will fly safely when above 100kts (part III). A subsequent note states “
The Captain can consider to reject a takeoff when the aircraft is above V1, only in the event that the aircraft is not able to ensure a safe flight.” Then part IV introduces ‘conditions’ and ‘indications’ of being unsafe or unable to fly, but without further definition.
Thus in both references, the reader has to establish appropriate meaning. Words are part of communication, but meaning (understanding) is often far from clear. What are ‘unambiguous indications’ that the aircraft will not fly safely?
IMHO many contributors in this thread appear to be content to quote SOP listings without further thought or qualification. If this reflects their understanding of the SOP, then with a critical event during takeoff, they might be ill-equipped to choose the correct course of action.