Boeing's best-seller

Air Philippines operates 12 Boeing 737s

The Boeing 737-200 is one of the world's best selling passenger planes, according to its manufacturer.

During its production run from 1966 to 1988, deliveries totalled 1,114 aircraft - nearly one-third of all 737s series ordered, Boeing says.

The plane that crashed in the Philippines, registration number RPC 3010, was one of 12 Boeing 737-200s operated by Air Philippines - the country's second biggest airline.

Although it was 22 years old, a Boeing spokesman said it was not unusual for such an aircraft to be still in operation.

Spokesman Sean Griffin said the plane had flown 79,522 flights totaling 68,475 hours, about average for a plane of that vintage.

The plane "can be operated essentially indefinitely, you do have to increase the maintenance requirements," said the spokesman.

The Boeing 737-200 is considerable dependable and straightforward to fly, according to aviation consultants.

Advanced 737-200

Air Philippines says its 737-200s can fly non-stop 4,635 km (2,880 miles) with a full passenger payload - about four hours at a cruising speed of 925km/h (575 mph).

All 737-200s are powered by Pratt & Whitney engines.

Boeing says that a typical 737-200 has a maximum range of 3,700 kmn (2,300 miles).

Depending on the interior configuration, the 737-200 can accommodate between 95 and 130 passengers.

An advanced version launched in 1971 incorporated aerodynamics improvements, automatic wheel brakes, more powerful engines and greater fuel capacity, gross weight and range.

These improvements allow the Advanced 737-200s to operate from airfields as short as 1,100 metres (3,600 feet).

All Air Philippines 737-200s are equipped with advanced avionics and an automatic flight control system, the company says.

Boeing says the plane's systems allow it to be self-sufficient and able to serve remote airfields without the need for ground support equipment such as jetways, electric power units and baggage conveyors.