Techniques of searching

Reconnaissance search
The aim of a reconnaissance search is to reduce the likely search area to a manageable size by searching for clues indicating where the people sought might be, so most search effort is in a high probability area. Four competent searchers quickly cover the intended route, and likely alternatives, of the missing people. Other points where missing people may stop are also checked (e.g. track junctions, huts, campsites and creeks). This method may be used for track and perimeter patrols throughout a search, and may be complemented by the use of small groups camping out on key features. Four-wheel drive vehicles and trail bikes can be used for track patrolling in most bush areas.

General search
This method is used to cover all the main features in an area of probability. Teams of four or five experienced and fast-moving personnel able to stay out overnight are used. Boundaries of the search areas are best defined by topographical features and unmistakably marked on the maps used. Search party progress can be indicated by toilet paper, preferably of different colours for different days. Several teams may be deployed to search parts of an area, with clear understanding of each team’s boundaries. The method of searching within their area is a matter for each search team. Generally, it is less physically demanding to search parallel with creeks and spurs rather than across them. As in reconnaissance searching, contact within the search team is maintained by voice, using names and numbers, interspersed with listening periods.

General search, as the name implies, includes all main features (i.e. spurs, creeks, tracks, etc.) but does not eliminate lesser individual features. Should a particular feature merit special attention because of its high hazard rating, it should be searched in closed-line formation, while open areas can be searched in extended formation. Areas of doubt should be eliminated by each individual search team, as that area may not be covered again unless information suggests further attention is warranted. It is not a wise practice to allot an unrealistically large area to a team, as tired or dispirited searchers are ineffective.

Close search
This is used where intermediate coverage is required. All lesser features are searched by small parties in addition to the areas covered in the general search.

Contact search
The contact or line search is usually the concluding phase of a search operation, but it can also be utilised earlier for a saturation coverage of a high probability area. Teams of up to 10 are normal, as larger numbers become slow and unwieldy. A line search is difficult to maintain, particularly in dense bush or rough, uneven terrain, and progress is always slow if the search is thorough. Large areas should be subdivided into manageable sections by using physical features and toilet paper markers. Generally, four runs each of 250 m width will be more efficiently searched than if the same party attempted one run of 1 km width.

Using the contact or line search technique, the team forms up in line so that each member maintains sight and voice contact with the person each side and is capable of visually searching the ground between. In dense scrub the spacing may be 3 m, while in open grass it may be 50 m. The leader should be located centrally to achieve best control. The spacing is maintained from whichever flanker is following the defined boundary route. The other flanker marks the progress with toilet paper indicators, and at the end of the sweep, these become the guide for the return sweep.

The search is continued sweep by sweep, until the allotted area is eliminated. This method is time consuming and requires large numbers of searchers. The searchers must look under, over, around and through everything in their sector, and miss nothing, as a negative report on completion will eliminate the area. It is important that the team leaders confer to ensure that boundaries are properly searched to avoid any areas remaining unsearched.

Search and rescue signals may be given by smoke (i.e. blanketing a smoky fire), by shouts, whistles, flashing of a mirror or torch, or by waving distinctive garments. The chief characteristic of these signals is their regularity and any signal repeated at any regular interval should be investigated. Signals commonly used in Australia (which may differ from those used overseas) include:

  • distress signal by a lost party—three signals together, regularly spaced
  • searchers looking for a lost party—one signal at irregular intervals to indicate progress
  • acknowledgment of a distress signal—searchers give one signal
  • recall signal—two signals at short intervals, followed by a minute without signals, and then repeat, or four signals together, regularly spaced.