Cockpit canopies
These use various designs and mechanisms, and the nature of the incident may have affected the stability of the aircraft systems. In an emergency, gaining access to the canopy should follow the guidance of a military aircraft specialist. This is usually carried out by using one of three methods:
Normal entry
Canopies can normally be opened by the aircrew using a manual, pneumatic, electronic or hydraulic system. Canopies can also be opened by a release mechanism on the outside of the aircraft; the method and design of opening mechanisms varies depending on the type of aircraft.
Open canopies will need to be secured in place to prevent them from slamming shut, which could injure personnel or aircrew.
Emergency entry
This method of entry only applies to aircraft fitted with a miniature detonating cord (MDC) or linear cutting cord (LCC). Instructions on how to open the canopy in an emergency are usually displayed on the outside of a military aircraft.
However, specialist advice should be obtained before personnel attempt to operate the cord. If this action goes ahead, the following precautions should be taken:
- All responders should be briefed
- An appropriate cordon around the canopy should be maintained
- All personnel should face away from the canopy
- Extend the cord by attaching a line, in order to operate it from outside the cordon
Forced entry
Forced entry using hydraulic rescue tools or crow bars should not be attempted under any circumstances. It is extremely difficult to assess the state of damage to an aircraft canopy following a crash. Forced entry could cause the canopy to ‘fire off’ if the canopy frame is interfered with.
Although highly dangerous and not recommended, other methods of forced entry such as cutting into the canopy, can be considered if there is a threat to life.
Ejection seats
It is possible to make ejection seats safe, however this should be carried out under the guidance of a military aircraft specialist. Due to the extensive range of ejection seat systems, sufficient training and familiarisation for firefighters would be difficult to achieve.
To make an ejection seat safe for rescue, the firing sequence needs to be controlled. This is usually carried out by pinning the ejection handles using sear pins, or by operating a safe seat lever.