Supporting arms synchronization of fires: altitude separation of FA and fixed-wing CAS

FA Journal, Sept-Oct, 2004 by John S. Gilbert

Joint fire support manuals provide guidance for altitude separation of FA and fixed-wing aircraft yet fail to present detailed instructions to fire supporters in calculating the "stay aboves" and "stay belows." This article shows the calculations that allow fixed-wing aircraft to fly closer to the artillery trajectory rather than having to use maximum ordinate (MAXORD) during the ordnance delivery portion of the flight profile.

[ILLUSTRATION OMITTED]

Suppression of Enemy Air Defenses (SEAD). The SEAD mission may be used when friendly aircraft can't complete their mission without critically exposing themselves to a ground threat, such as air defense artillery (ADA). (Throughout this article, any ground threat to friendly aircraft will be referred to as "ADA.") Indirect fires suppress the ADA via SEAD missions and mark the target (threat to ground forces) for the aircraft to attack. If ADA is suppressed, it's less likely to acquire and engage the aircraft.

There are two types of SEAD missions: standard, and non-standard.

There are two types of standard SEAD missions: continuous and interrupted. The continuous timeline has rounds impacting at -1, -:30, 0, +:30 and +1 minutes. The mark is at -:30 for white phosphorous (WP)/red phosphorous (RP) or -:45 for illumination on the deck (IOD). The interrupted timeline has rounds impacting at -1 and -:30. The mark is at -:30 for WP/RP or -:45 for IOD.

The non-standard timeline can include any coordinated and deconflicted supporting arms, as long as they are tailored to support the ground scheme of maneuver, suppress the ADA and mark the attack target.

Marks can be provided by indirect fire, direct fire or by laser. Laser marks (i.e., infrared pointers) and direct fire should be initiated 30 seconds before the close air support (CAS) time-on-target (TOT) and continued until 30 seconds after the CAS TOT. This provides Dash-2 (second aircraft of the two-ship section) the same redundant marks to orient onto if Dash-1 does not release its ordnance (Dash-2 usually orients off Dash-1's effects).

Types of Separation. Aircraft and SEAD fires may be separated by distance or time. This is commonly subdivided into lateral, time and altitude separation or any combination of these.

Lateral separation is effective for synchronizing indirect fire and aviation attacks against two adjacent targets. A specific distance separates the suppression fires from the targets aircraft are attacking. The minimum separation distance between suppression targets and aviation attack targets varies and should be based on the caliber of indirect fire fired at the suppression target. Based on the fixed-wing aircraft's ordnance, the pilot determines how far to stay above the fragmentation pattern.

Each unit must develop a minimum lateral separation for friendly units used in conjunction with indirect fires. A recommended minimum is 1,000 meters for artillery (155-mm) and 400 meters for mortars (81-mm). Units are not recommended to pass underneath active mortar gun-target lines (GTLs).

Establishing a temporary, informal air-space coordination area (ACA) is one method of maintaining lateral separation. For example, such an ACA could be, "Stay east of the Euphrates River."

If fixed-wing aircraft are attacking a target below 2,000 feet above ground level (AGL) in conjunction with artillery or mortars, the same lateral separation restrictions should apply. This is based on the vertical portion of the fragmentation pattern of indirect fires (155-mm) plus a 1,000-foot safety buffer.

Time separation may be required when aircraft can't be routed away from indirect fire trajectories or suppressed targets or must use extremely low ingress and egress flight profiles. This technique requires SEAD fires to be coordinated with the routing of aircraft so that although aircraft and SEAD fires occupy the same space, they don't do so at the same time.

Time separation should be used with mortar fires suppressing a fixed-wing aircraft target. It allows suppression before and after the CAS attack while not forcing the aircraft to stay above the mortar trajectory.

Mortar trajectories can be as high as 10,000 feet AGL. At this altitude, fixed-wing aircraft may have difficulties acquiring the mark or target and the forward air controller (FAC) may have difficulty acquiring the aircraft.

The SEAD interrupted mission is a good use of time separation while synchronizing mortars and fixed-wing aircraft against the same target. If suppression is desired after the aircraft attack, a separation of two minutes from the CAS TOT allows Dash-2 to clear the area before mortars fire again. This is based on the mortars' average time-of-flight (TOF) and an additional 15-second safety factor in case Dash-2 is late or mortars fire early.

A separation of one minute and 30 seconds from the CAS TOT is recommended for artillery (based on a smaller average TOF). Using time separation for artillery is not recommended and will not be necessary when using altitude separation.