JP 3-50 National Search and Rescue Manual Vol I - US Navy

marked by a fluorescent grenade marker or a smoke/drift signal
in daylight, or a strobe light at night.
D. Safety procedures for aircraft are a major concern. If no
airspace reservations are provided, aircraft SRUs are responsible for
complying with all FAA and ICAO requirements. During large-scale
searches, the SMC normally obtains a SAR airspace reservation from ATC.
When ATC facilities are unable to provide airspace reservation for
search aircraft, the SMC and OSC will normally provide safety and
alerting services. All aircraft within the area will maintain their own
VFR separation. When instrument meteorological conditions (IMC) exist
in the SAR airspace reservation, aircraft should not be assigned for
visual searches. In the absence of adequate ATC facilities, aircraft
control in the SAR area will often be advisory rather than directive.
Unless the OSC has a qualified and experienced air controller to handle
air traffic, each aircraft commander should make technical air safety
decision.
1. Assigned altitudes. The OSC should monitor the progress of
arriving or departing aircraft, and assign altitudes to ensure
separation of aircraft and clearance of obstructions.
Assigned altitudes may not provide separation between aircraft
unless all aircraft have the same altimeter setting.
Altimeter settings may be obtained from ground stations or
vessels, and are based on prevailing atmospheric pressure. A
common setting should be assigned to all aircraft on scene
unless the search area is large. "Flight level" is used over
ocean areas where sea level barometric pressure is not
available. Flight levels provide vertical separation of
aircraft because a common altimeter setting of 29.92 is used.
They should never be used to assign altitudes for low-level
searches.
2. Military Assumes Responsibility for Separation of Aircraft
(MARSA). When the SMC and OSC direct search aircraft to
specific search altitudes, they must ensure that aircraft do
not interfere with each other. The SMC uses search altitudes,
CSP, and direction of creep to provide aircraft separation.
In addition, the OSC or pilot provides vertical separation
during descent and ascent. Participating search aircraft
should file flight plans with the phrase "MARSA and safety of
flight in search area" noted in the remarks section.
3. Aircraft descent procedures via CSP. When several search
areas are involved and a large total area is being searched,
all search aircraft should be directed to file for either
their CSP or the center point of their assigned search areas.
If altitudes below are clear, the aircraft should descend to
search altitudes and keep the OSC advised.
4. Cancellation of air search. If visibility in the search area
has deteriorated so that flight safety becomes a concern, the
OSC should suspend searching and direct arriving aircraft to