Lion Air chief govt Edward Sirait on Wednesday night rejected some media studies quoting KNKT that the airline’s Boeing 737 passenger jet that crashed on October 29 was not airworthy since its penultimate flight from Denpasar to Jakarta.
It had been cleared as airworthy by Lion Air engineers on that flight in addition to its last flight, KNKT investigator Nurcahyo Utomo mentioned earlier within the day.
“I feel pilots can decide for themselves whether or not to proceed,” mentioned Lion Air managing director Daniel Putut, a former pilot.
Utomo, in distinction, pointed to a number of issues, together with the “extreme” subject of stall warnings occurring in tandem on the Bali-Jakarta flight that have been sufficient for the KNKT to find out the flight shouldn’t have continued.
Info retrieved from the flight knowledge recorder confirmed the “stick shaker” was vibrating the captain’s controls, warning of a stall all through many of the flight. The captain was utilizing his controls to carry the aircraft’s nostril up, however an automatic anti-stall system was pushing it down.
Pilots flying the identical aircraft a day earlier had skilled the same downside, en route from Denpasar, Bali to Jakarta, till they used switches to close off the system and used guide controls to fly and stabilise the aircraft, KNKT mentioned.
“The flight from Denpasar to Jakarta skilled stick shaker activation throughout the takeoff rotation and remained energetic all through the flight,” the committee mentioned.
“This situation is taken into account un-airworthy” and the flight ought to have been “discontinued”.
The pilots of that flight reported issues to Lion Air’s upkeep group, which checked the jet and cleared it for take-off the following morning.
Former Boeing flight management engineer Peter Lemme mentioned stick shaker activation was “very distracting and unnerving”.
“It isn’t one thing you ever wish to have occur as a pilot,” he mentioned.
Utomo mentioned the company had not decided if the anti-stall system, which was not defined to pilots in manuals, was a contributing issue.
“We nonetheless do not know but, if it contributed or not,” he mentioned in response to a query. “It’s too early to conclude.”
In an announcement, Boeing drew consideration intimately to a listing of airline upkeep actions set out within the report however stopped wanting blaming floor employees or pilots for the accident.
Revised anti-stall system
The producer, which has mentioned procedures for stopping an anti-stall system activating by chance have been already in place, mentioned pilots of the penultimate flight had used that drill however famous the report didn’t say if pilots of the doomed flight did so.
Boeing’s assertion didn’t make any reference to a revised anti-stall system launched on the 737 MAX which US pilots and Indonesian investigators say was lacking from the working guide.
Boeing says the process for coping with a so-called runaway stabiliser, beneath which anti-stall methods push the nostril down even when the aircraft shouldn’t be getting into a stall or shedding carry, had not modified between an earlier model of the 737 and the newly delivered 737 MAX.
Pilots nonetheless say the management column behaves in another way in sure circumstances, which may confuse pilots who’ve flown the sooner mannequin.
Indonesian regulators have been urged after earlier accidents to enhance their oversight of upkeep and pilot coaching.
The report supplied new suggestions to Lion Air on security on high of earlier suggestions concerning the flight guide which have already been applied by Boeing.
Lion Air CEO Sirait mentioned the airline would adjust to KNKT’s suggestions which included guaranteeing pilots made the correct determination on whether or not to proceed a flight.
Authorities have downloaded knowledge from the flight knowledge recorder, however are nonetheless on the lookout for the cockpit voice recorder (CVR).
Indonesia plans to herald a ship from Singapore in a position to keep in place with out dropping anchor, to assist with the search.