PS-INP-155 · r1 INPUT INFERRED ENGAGED

CONTROL PATH DIVERGENCE

Two ways of issuing the same command disagree about which one happened last.

01 DEFINITION

Condition in which one function is reachable through both a physical control and a screen control, and which of the two settles the resulting state is not defined, so the paths produce different states from the same intent.

02 CONDITIONS

UNCERTAINTY CONFLICTING Both paths report success and the states they leave behind are not the same.

TIME PRESSURE MODERATE There is time to issue the command once, and not time to verify which path took effect.

ERROR ASYMMETRY ASYMMETRIC Acting on the stale path costs more than repeating an action that had already taken.

OPERATOR STATE DEDICATED The operator knows both paths exist, which is why neither is checked.

03 WHERE IT APPEARS

MARITIMEThe surface being touched and the person touching it move on the same swell.

AVIATIONAn input is made in conditions the input device was bench-tested without.

ENERGYA control room laid out once is worked by people whose reach was never measured.

INDUSTRIALThe operator acts through gloves the interface was not drawn for.

04 WHAT AEON WORKED THROUGH HERE

The same action could be taken through a physical control or through a surface, and the two did not always agree on what had happened. The disagreement was rare and arrived when it was least expected. The work was on which path is authoritative, and on how the other one shows that it is not.

What stays unresolved is how a physical control and a screen control divide one function without dividing the state — the operator reaching for the dial is not asking a different question from the one touching the screen.

05 LINKED TERMS

PS-MOD-073 MODE-BOUND CONTROL MAPPING PS-COO-136 SHARED STATE DIVERGENCE PS-INP-163 INPUT WITHOUT INTENT PS-INP-169 BLIND OPERATION LOST PS-COO-208 THE ONLY PATH IS A PERSON