MANILA • At the centre of the fight for Marawi has been the OV-10 Bronco, a Vietnam War-era plane that the Philippines has deployed along with jets like the FA-50 Fighting Eagle, a light combat fighter that the government in Manila has bought in waves from South Korea.

The OV-10 has been photo graphed flying in formations over the city in between bombing runs.

Initially conceived in the 1960s in the United States, the OV-10 offered American forces in Vietnam a simple, rugged plane that could carry out close-air support for troops on the ground and take off from short runways.

It remained in service in the US military until the 1990s, undertaking operations in the Gulf War.

The Philippines acquired more than 20 used OV-10s from the US in the early 1990s and more from Thailand in 2004.

The turboprop plane provided a way for the country to attack enemies from the air while keeping to a tight budget.

But the plane's use has come into question as it has aged, especially following crashes in 2010 and 2013. The military temporarily grounded all eight of its remaining OV-10s in 2013 but defended their continued use, noting that they had received numerous upgrades, according to a report by the Philippine Star newspaper.

However, the country has signalled a desire this year to begin replacing the remaining OV-10s by opening bidding for new close-air support planes.

WASHINGTON POST