* Lion Air's Boeing 737 MAX jet crashed in Oct, killing 189
* Cause of Indonesian crash still being investigated
* KNKT to send delegation to Ethiopia to help with probe (Adds quotes from agency head)
JAKARTA, March 15 (Reuters) - Indonesia will hasten the release of its report on the October crash of Lion Air Boeing 737, the head of the nation's transport safety committee said on Friday.
The crash, which killed all 189 people on board, was the first worldwide of Boeing Co's new 737 MAX jet. A second deadly incident occurred on Sunday with the crash of an Ethiopian Airlines MAX jet that killed all 157 people on board.
Soerjanto, the head of safety agency KNKT, told Reuters the investigation into the Lion Air crash would be speeded up and the report will be released in July-August, earlier than its original timeline of August-September.
The cause of the Indonesian crash is still being investigated. A preliminary report by KNKT in November, before the retrieval of the cockpit voice recorder, focused on maintenance and training and the response of a Boeing anti-stall system to a recently replaced sensor, but gave no reason for the crash.
Indonesia plans to send a flight inspector and an official from KNKT to Ethiopia to help with the probe into Sunday's crash, pending approval from Ethiopian authorities, Soerjanto said.
"Yesterday morning, we communicated with Boeing, the U.S. Federal Aviation Administration (FAA) and the National Transportation Safety Board in Ethiopia, but we have yet to exchange information," Soerjanto said, adding that they had requested the results of the investigation into the plane's black boxes.
"As there is no certainty from Boeing and FAA, we will continue to advocate for the Boeing Max 8 planes to stay grounded."
U.S lawmakers said on Thursday that Boeing Co's 737 MAX 8 and 9 planes will be grounded for weeks if not longer until a software upgrade can be tested and installed, as officials in France prepared to begin analyzing the black boxes from a jet that crashed in Ethiopia.
(Reporting by Cindy Silviana; Writing by Fanny Potkin; Editing by Muralikumar Anantharaman)
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