The Directorate General of Civil Aviation (DGCA) on October 17 said the incident of smoke filling the cabin of SpiceJet's Goa-Hyderabad flight last week was a result of the engine oil entering into the aircraft's air-conditioning system.
The incident was reported on the SG 3735 GOI-HYD flight, operating on Q400 series aircraft, on the night of October 12.
During the preliminary investigation, "evidence of engine oil was found in engine bleed-off valve which had led to the oil entering the aircraft air-conditioning system resulting in smoke in the cabin", DGCA said in a statement.
SpiceJet was subsequently asked to send engine oil samples of all 14 aircraft of its Q400 fleet , which use PWC 150A Engine, to Pratt & Whitney Canada "to ascertain presence of metal and carbon seal particles", the aviation sector regulator added.
The carrier was also told to conduct an "inspection of bleed-off valve screen and housing for evidence of oil wetness".
"In light of the above incident and also a similar incident in the recent past involving PWC 150A Engine, which had also shop visited Standard Aero Singapore for overhaul, SpiceJet was directed that no engine shall be sent to Standard Aero - Singapore till the investigation is completed," the statement noted.
'Oil samples to be drawn every 15 days'
DGCA has asked SpiceJet to adopt a number of additional measures, which includes the drawing of engine oil samples at "every 15 days" instead of 30 days at present. The samples are to be sent to Pratt & Whitney Canada to ascertain presence of metal and carbon seal particles.
SpiceJet has been directed to conduct "one-time boroscopic inspection of all operational engines within one week and completion of the boroscopic inspection on 3 engines, which have been received from Standard Aero, Singapore by tonight", the regulatory body said.
The airline has further been told "to introduce inspection of bleed-off valve screen and housing for evidence of oil wetness during every weekly check".
SpiceJet would also be required to conduct "immediate inspection of Magnetic Chip Detectors (MCD) for presence of any metal particles on reporting of fault 938 in the central display system, which otherwise is a class 2 fault and calls for inspection within the next 65 flight hours", as per the DGCA statement
"In case of detection of any metal particles, boroscopic inspection of the engine shall be carried out prior to release of aircraft," it further said.
Discover the latest Business News, Sensex, and Nifty updates. Obtain Personal Finance insights, tax queries, and expert opinions on Moneycontrol or download the Moneycontrol App to stay updated!