NAL Saras transport flies again after 8 years

An improved prototype of the Indian Saras light transport aircraft has completed first test flight after being grounded for 8 years.

The PT1N, an improved and upgraded version of the first prototype, flew for 35 minutes piloted by ASTE Test Pilots Wg Cdr B Panicker & U P Singh along with Flight Test Engineer Bhat.

The aircraft has undergone 10 modifications that improve the aerodynamic characteristics and make it more pilot friendly.

Among the major modifications include a larger metallic Rudder for increased controllablility, stall warning system, more efficient electrical system, improved flight control systems and an optimal engine nacelle.
The program was grounded following a fatal crash involving the second prototype PT-2, during flight testing in 2009 killing three on board flight crews.

Investigation found that an incorrect relight procedure devised by the aircraft designer National Aerospace Ltd (NAL) and adopted by the flight crew at insufficient flight altitudes (9400 ft) lead to rapid loss of altitude and abnormal behavior of aircraft resulting in the accident.

Contributing factors to crash included:

• Lack of crew coordination and cockpit procedures.
• Handling of the controls.
• Non-aborting of flight by the crew in coordination with the flight test Director after failure of first relight attempt.
• Devising engine relight procedures by NAL without consulting the propeller manufacturer.
• Controllablity issue with the aircraft being in developmental stage, as pilot had complained of excessive control forces.
• Lack of clarity from Engine OEM Pratt & Whitney considering the aircraft being experimental aircraft and whether to keep the propeller in “feather” or “Fine”for engine relight procedure in air.

Saras is configured as a low wing monoplane with T-tail powered by two Pratt & Whitney Canada PT6A -67A Turboprop engine in the pusher configuration.

Each engine is fitted with a 5 bladed MT propeller made of Aluminum alloy incorporating a variable pitch, constant speed unit and a propeller over speed governor. The engines are installed on the stub wings on either side of the rear fuselage.

The standard design configuration is provided with seating for 14 passengers, seated 2 abreast. Front and rear baggage compartments are provided for the purpose of accommodating the baggage.

Indian Air Force had earlier committed to acquire 15 Saras aircraft for cargo and light transport roles, as it had an pressurized cabin, to augment the non-pressurized Dornier Do 228 fleet.

By the end of 2019, NAL plans to fly a production-standard version for air-worthiness certification.