The fire seals prevent the flow of fire or flammable gasses into specified areas when the upper and lower cowls are closed.

The power plant is divided into two fire zones which are isolated by fire seals. The fire seals, which include firewalls and fireproof fairings, are made to prevent the movement of fire between zones. All the areas in which fire could occur, or could be damaged by fire, have material parts which are fire resistant.

The fire seals include the thrust-strut fire seal, rear-mount fire seal, bleed-air duct seal and the firebox seal. The material of these seals is fireproof flexible-rubber.

There are two thrust-strut fire seals. One gives protection at the elliptical opening where the thrust strut goes through the fixed cowl. The seal attaches with bolts to the fixed cowl and with a clamp to the thrust strut. The other is at the rear of the firebox, where there is an opening for the thrust strut. A circular duct with a square flange attaches to the firebox. The thrust strut goes through the circular duct and into the firebox. The seal attaches with clamps around the thrust strut and the circular duct.

The rear-mount fire seal gives protection at the opening where the rear mount goes through the fixed cowl. The seal attaches with bolts to the fixed cowl.

The bleed-air duct seal gives protection where the bleed air duct goes through the circular opening in the fixed cowl. It is a bellows seal which attaches with bolts to the fixed cowl and with a clamp around the bleed duct.

The firebox seal gives protection between the firebox and the bypass duct. It is a tubular seal which attaches to the edge of the firebox.