Fire and Smoke — Page 167, Lesson 260

I want to walk you through two important fire-related topics from the operational procedures manual: crash axes and crowbars, and overheated brakes. Let's start with the equipment requirements. For crash axes and crowbars, the regulation is based on aircraft size. Any aeroplane with a maximum take-off mass exceeding 5,700 kilograms — that's about 12,500 pounds — or any aeroplane with a passenger seating configuration of more than nine seats, must carry a crash axe or a crowbar. That tool must be located on the flight deck, so the flight crew can reach it quickly in an emergency. If the aeroplane has a passenger seating configuration of more than 200, the rules get stricter. You're then required to carry an additional crash axe or crowbar, and this second one must be stowed in the rearmost galley area. There's also a specific stowage rule: any axes or crowbars stowed in the passenger cabin must not be visible to the passengers. That's to avoid causing alarm. Now let's move to overheated brakes — this is a critical fire hazard you need to understand thoroughly. The heating effect of the aircraft braking system depends on two factors: the mass of the aircraft and the rate of deceleration required. The heavier the aircraft and the harder you brake, the more heat you generate. Under normal braking, the system can usually dissipate that heat. But when braking is abnormal — and I want you to note the three specific scenarios given — an abandoned take-off at maximum take-off mass, a turn back after take-off, or a landing on a short runway — then excessive heating of the brake system can occur. That excessive heat is concentrated in the brake units at the wheels, and it can lead to brake fires or inadequate dispersal of the generated heat. Here's a critical timing fact: brake packs continue to heat up, and they reach their maximum temperature, up to 30 minutes after you've finished using them. So even after you've stopped braking, the temperature is still climbing. This delayed heating can cause several dangerous consequences: tyres can ignite or explode, brake components can weld together — that's called seizing — and you can get greatly reduced braking action. That reduced braking happens both during the period of hard braking itself and during taxiing after you've reduced to a safe speed. Because of these risks, it is essential that you maintain other speed-reducing methods. Specifically, do not shut down engines that could provide reverse thrust. You need every tool available to slow the aircraft without relying solely on the brakes. Due to the way braking systems are constructed, the components remain critically hot for considerable periods. The possibility of fires only reduces slowly. So you must calculate and wait for the expiry of the brake cooling time before attempting a subsequent take-off. You cannot just assume the brakes have cooled. Where hot brakes are concerned, it is essential that fire prevention and fire fighting personnel and equipment are in attendance. If you are taxiing the aircraft with hot brakes, a fire truck must follow you. You must maintain two-way communications with the fire crew, either directly or via air traffic control. You also need to give careful consideration to where the aircraft is to be parked — think about the proximity of other aircraft, buildings, and refuelling points. And you must consider the possibility of an emergency evacuation of the passengers. Let me show you the relevant diagrams. So to summarise the key points on overheated brakes: the heat comes from mass and deceleration rate, abnormal braking scenarios are the main concern, brake packs peak in temperature up to 30 minutes after use, and you must keep engines running for reverse thrust, calculate cooling time before another take-off, and coordinate with fire crews on the ground.