VOLUME I Multinational Maritime Tactical Instructions and Procedures

MTP 1(D), Vol. I
(b) NOT RELEASABLE
(2) Broadband Contact by Passive Sonar or Passive Sonobuoy. Consistent tracking of
a firm contact with courses, speeds, or other indications, which are compatible with submarine characteristics,
and are confirmed by at least one other type of sensor.
(3) Radar Contact. Confirmation of a radar contact by at least one of the following, obtained simultaneously
or in close sequence:
(a) Search receiver contact on the same bearing and displaying characteristics of a distinctive
submarine radar.
(b) Active or passive sonobuoy or MAD tracking.
(c) Sonobuoy and MAD contact near datum.
(d) Sonar contact having submarine characteristics.
(e) Lofar contact evaluated as submarine.
(4) NOT RELEASABLE
(5) MAD Contact. MAD is normally a confirmatory sensor used in conjunction with other sensors.
NOT RELEASABLE
(6) Narrowband Passive Sonar Contact. A lofar signature is evaluated as a submarine; if
known, the type of submarine is to be included in the classification.
c. POSSUB (Possible Submarine Contact). A contact on which available information indicates
the likely presence of a submarine, but there is insufficient evidence to justify a higher classification.
A classification of POSSUB may be given under any one or more of the following conditions:
(1) An object thought to be a surfaced submarine, submerged submarine, submarine periscope, or
snorkel is sighted; but, because of poor visibility or the lack of competence of the observer to recognize
such objects, the criteria for CERTSUB cannot be supported.
9-20 ORIGINAL