A fine study was carried out on the on board telephone (TB). Whereas it is the only prescribed way of communication on the Maritime Patrol aircraft, there are two other types of communications because of the saturation of this channel: shouted communications potentially addressed to all the acoustics operators, and whispered communications, from one operator to the next, over his shoulder. The communications in the TB are audible by the complete staff.

A certain number of failures was noted concerning the TB. Because of its saturation, there are delays in the notification of messages: delayed information does not have the relevance it would have had in real time. Incomprehension, misunderstandings also come from a high information traffic. But lots of questions remain: Which is the role of the TB for the multiple recipients of information ? Is the activity of the latter disturbed by a continuous speech flow in the TB ? Is their situation awareness better thanks to the TB ?

In fact, in order to "clear" the TB, it would be possible to propose automatic sendings of statistical data and automation of certain exchanges by HMI. But all cannot be, in the same way, automated, and certain information must remain and be sent through the TB.

TB: Fine categorizations based on visual observation:

For example, in the exchanges concerning the acoustic data, there are fine categorizations, based on precise visual descriptions, which are, in fact, irreplaceable. These statements, such as noun phrases, are operative [3] [5] and identify a phenomenon visually observed on the screens of the interface by categorizing it:

apparition de contact, fréquence haute, courte distance

CPA très courte distance sur la 4

fréquence plus basse sur la 8

These categorizations are done on millimeters of signal or on very similar shapes of curves, quite difficult to verbalize.

TB: Collective and certainty

In order to define the type of information conveyed by the on board telephone, a more detailed study was carried out. Astonishingly, the TB miss the pronominal forms of first person, like je. In fact, an operator, seeing an interesting element on its screen announces it, first in a shouted voice with the first person je, then in the TB with the impersonal form on, like:

A3 : -- eh / j'ai XZ sur la 24

A1 : -- ah ouais / ah ouais ouais ouais:

A3 : -- on a XZ sur la 24 (TB)

Actually, on is not only impersonal, it is also the expression of the collective. Even if one operator obtains information on its screen, when information passes through the TB, the information becomes collective.

This passage out of the telephone -> into the TB seems to be related to the certainty of information. Je, subjective by definition, is absent of the TB, just as the forms ouais, which alternate with oui. In a mission, we counted 200 ouais modulating answers to requests for information, and we listed only one of them on the TB, corresponding to a very special moment: one of the operators was requested to come on a decision and he was formulating assumptions. To summarize, the information transmitted by the TB is fine and precise, as certain as possible, and ready to be re-utilized by the collective.

Some recommendations concerning the on board telephone

We proposed the automation of certain exchanges, via data links between the different interfaces, but we took care not to deteriorate the collective work, which requires the construction of common knowledge[6] through communication. Concretely, we proposed the conception of a specific screen dedicated to the presentation of the tactical situation, allowing the acoustics experts to know the position of the buoys released by the tactician and their identification. This source of information must permit to reduce the verbal exchanges and to reach information more quickly and more effectively. In compensation, we alerted the designers about the risk to automate the exchanges concerning, in particular, the visual analysis of the signals detected by the operators.