*

Report could provide early details into world's worst

aviation

disaster in a decade

*

Probe has been dogged by questions over lack of

information

*

India reversed course and now allowing UN specialist

observer

status - sources

(Recasts with sourcing that preliminary report expected by

Friday, writes through)

July 8 (Reuters) - A preliminary report into the crash

of an Air India jetliner that killed 260 people in June is

expected to be released by Friday, a step that could provide

early details into the world's worst aviation disaster in a

decade, three sources said on Tuesday.

While the report from Indian investigators could be made

public on Friday, the sources with knowledge of the matter

cautioned that plans could change and there was no clarity on

how much information would be available in the document, which

comes about 30 days after the June 12 tragedy.

The sources spoke on condition of anonymity because they

were not authorised to speak to media.

India's Aircraft Accident Investigation Bureau, which is

leading the probe under international rules, did not respond

immediately to a request for comment outside normal business

hours.

Most air crashes are caused by multiple factors. The

investigation is focusing at least partly on engine thrust,

Reuters reported last month.

The London-bound Boeing 787 Dreamliner, which started

losing height after reaching an altitude of 650 feet, crashed

moments after takeoff from Ahmedabad, killing 241 of the 242

people on board and the rest on the ground.

Earlier on Tuesday, India's ANI news reported that

investigators from the AAIB submitted the preliminary report on

the crash to the civil aviation ministry, citing sources.

Reuters could not immediately confirm the report.

The probe has been dogged by questions over lack of

information, after investigators took about two weeks to

download flight recorder data after the crash. The Indian

government held only one press conference on the incident, and

no questions were taken.

However, India reversed course on an earlier decision

reported by Reuters to prevent a U.N. aviation investigator from

joining the probe, two senior sources said.

A specialist from the U.N.'s International Civil Aviation

Organization (ICAO) was granted observer status, following an

unusual request by the agency to offer its support.

ICAO declined to comment, adding in a statement that any

public discussion of "cooperative arrangements," would require

authorisation by the state.

The crash is challenging the Tata Group's ambitious campaign

to restore Air India's reputation and revamp its fleet, after

taking the carrier over from the government in 2022.

India is banking on a boom in aviation to support wider

development goals, with New Delhi saying it wants India to be a

job-creating global aviation hub along the lines of Dubai, which

currently handles much of the country's international traffic.

A panel of Indian lawmakers will review safety in the

country's civil aviation sector and has invited several industry

and government officials to answer questions on Wednesday, with

topics set to include the recent plane crash.