FSSL (fire support safety line)

A fire support safety line, abbreviated FSSL, is a fire support coordination measure used in NATO and allied land-warfare doctrine. A manoeuvre commander draws it on the ground to protect friendly forces from indirect fire. Short of the line, indirect fire systems do not fire except on the request or approval of the commander who established it. Beyond the line, they may fire at any time without danger to friendly troops.

The line does two jobs at once. It shields a brigade or division from indirect fire delivered by units outside its formation, and it speeds up attacks on enemy targets on the far side, because supporting artillery does not need further clearance to engage them. The FSSL is a military doctrine term. It is not a procurement classification or a tender data field.

How the FSSL restricts and permits indirect fire

NATO doctrine groups the FSSL with the restrictive fire support coordination measures. These measures exist mainly to safeguard friendly forces, so they require specific coordination before an affected engagement can take place. The FSSL is similar to the No-Fire Line, but it applies specifically to indirect fire systems.

The permissive side is what sets it apart. Higher-level fire support units can engage targets beyond the line without extra coordination with the establishing level. A NATO-related expert report on fire support practice describes the line as set in front of each brigade or division. It protects own troops against fire from units that do not belong to, or are not allocated to, that formation.

Who sets an FSSL and how it is drawn

U.S. Army doctrine in FM 3-09.30 states that division and brigade commanders normally establish the FSSL. A battalion-size force may sometimes do so. The line should follow well-defined terrain features and sit as close to friendly forces as safety and the tactical situation allow.

• It can be a line stretched in front of the force.
• It can be a circular line where the restriction applies to a particular area.
• Under NATO symbology, it is shown as a dashed black line marked "FSSL", with the establishing headquarters written above the line at the ends and the effective date-time groups written below.

FSSL compared with the FSCL, CFL and NFL

Allied doctrine recognizes several fire support lines, and each answers a different coordination need.

• Fire Support Coordination Line (FSCL): beyond it, fires must be coordinated with affected commanders. Short of it, fires must be coordinated with the establishing commander. It exists chiefly to speed attacks on surface targets beyond it, especially by aircraft. A historical analysis of the FSCL, available from DTIC, traces it to the earlier "bomb safety line" and records its introduction into U.S. artillery doctrine in 1961.
• Coordinated Fire Line (CFL): a permissive line beyond which conventional indirect fire may fire at any time within the establishing headquarters' boundaries without further coordination.
• No-Fire Line (NFL): short of it, artillery or naval guns do not fire without the supported commander's approval. It is used mainly at joint and multinational force level.
• FSSL: the indirect-fire line that protects a formation from outside fires while freeing higher-level fires beyond it.

How NATO records the term

NATO treats the FSSL as an official term. The AAP-6(C) joint military symbology standard lists "Fire support safety line (FSSL)" and attributes its definition to the NATO fire support doctrine AArtyP-5. The NATO abbreviations glossary AAP-15(2010), available from DTIC, gives "FSSL" as the standard abbreviation for "fire support safety line". It also gives the French equivalent, "ligne de sécurité des feux d'appui".

What FSSL means for suppliers bidding on Canadian contracts

FSSL is a tactical term, and the doctrinal sources that define it do not set procurement or contract requirements. The CanadaBuys portal and the federal contract search do not use it as a category, data field or classification. Suppliers will not find it in standard terms and conditions or bid instructions.

Bid teams should therefore read any defence solicitation on its own wording. If a requirement refers to fire support coordination measures, this entry explains what the FSSL is. A supplier cannot assume that it carries any compliance obligation unless the solicitation says so.