Overview of the Singapore Self-Propelled Howitzer (SSPH). The SSPH is a 155mm, 39 calibre, tracked howitzer. The SSPH was locally developed by ST Engineering Land Systems, and commissioned in 2003. The SSPH is operated by a crew of four comprising the Gun Commander, Charge Loader, Ammo Loader and Driver. Safe areas within the turret are demarcated for each serviceman. Their roles are as follows and designated positions within the SSPH are as indicated in Figure 1: 

1. Gun Commander. The Gun Commander commands and supervises the gun detachment. He is responsible for all equipment in the detachment as well as all aspects of operation of the SSPH.
2. Charge Loader. The Charge Loader is responsible for preparing and loading the correct charge for the firing of the ammunition.
3. Ammo Loader. The Ammo Loader is responsible for loading the correct ammunition to be fired.
4. Driver. The Driver is responsible for driving the SSPH.

Lowering of Gun Barrel. To lower the gun barrel, the following drills are stipulated in the SSPH operator manual: 

1. The Gun Commander conducts visual checks to ensure that the area surrounding the gun barrel is free from obstacles.
2. The Gun Commander also conducts visual checks to ensure that the crew in the cabin remain in their respective safe operating positions and are not in the travel path of the barrel.
3. The Gun Commander will sound off “clear away” to warn the gun crew of impending barrel movement and will sound off “standby” before lowering the barrel.

Safety Precautions. In an emergency situation that requires the gun barrel or other mechanical moving parts in the turret to immediately cease movement, either the Gun Commander, Charge Loader or Ammo Loader can activate an emergency stop button located within reach of their respective operating positions. 

Maintenance Work. In the event that the gun requires maintenance work during training and operations, a team of Army technicians will be activated onsite and takes charge of the SSPH. Given the diagnosis and maintenance works required, the Army technicians may require the assistance of the Gun Commander. Army technicians are also trained and required to abide by the same drills and safety protocols as the SSPH crew.