The sailing venue for the Tokyo 2020 Olympics could be moved as part of a widening review into original plans for the Games.
Competition is due to take place at the Wakasu Olympic Marina, but according to reports, the fact it is within the approach zone for one of Haneda Airport's runways could derail those plans.
That is because helicopters will need to fly above the venue to film the races, disrupting flights at the country's busiest airport.
With the building of the marina in Tokyo's Kota Ward on ice, Japanese newspaper The Yomiuri Shimbun says the metropolitan Government is now looking at the possibility of moving the sailing competition to Inage Yacht Harbor in Mihama Ward, Chiba - further along Tokyo Bay.
According to Tokyo 2020's bid document, building the new marina would cost JPY¥9.2 billion (£52.1 million/$87.8 million/€65.7 million) and there are questions about how well used it would be after the Games.
Inage Yacht Harbor opened in 1982 and is around 25 kilometres from the planned site for the Athletes' Village.
The International Sailing Federation said it understands there are "several options" for the sailing competition at Tokyo 2020.
Secretary general Jerome Pels told insidethegames: "We haven't had any formal proposals of changes but we know that they are looking at their plans.
"We need to find out exactly why they want to make the changes [but] so far we haven't been asked to look at anything.
"Tokyo are not really sure what they want to do."
He added: "Our venues are not just about construction, the filed of play is in a natural environment so we would need to look at that - everything from currents, depth, whether we're sailing close to the shore line."
In June, Tokyo 2020 officials were warned any changes to venues will only be allowed to be made with the full support of the relevant world governing body.
Aside from a possible change in sailing venue, plans to construct a canoe slalom course in Kasai Rinkai Park on reclaimed land are being reviewed.
Basketball and badminton could also be moved to existing sites instead of being staged at newly built venues on a waterfront area near the Olympic Village.
John Coates, chairman of the International Olympic Committee's Coordination Commission, spoke during June's visit of plans to relocate the canoe slalom course.
"This is consistent with President [Thomas] Bach's 2020 Working Agenda that we want to see venues that are sustainable and have legacy," he said.
"We want to see the use of more existing venues.
"We want to see the use of more temporary venues."
The sailing venue review is reportedly being coordinated by the metropolitan Government, with the relevant sports federation officials in Japan and overseas to be consulted.
June 2014: Tokyo 2020 warned they must get support from International Federations for any venue changes
June 2014: Tokyo 2020 will show how "resilient" Japan is claims Coates as IOC Coordination Commission begins
June 2014: Tokyo 2020 revising Olympic venue plans to combat spiralling costs
May 2014: Tokyo says sayonara to National Stadium as row over redesign continues
May 2014: Downscaled design approved for Tokyo 2020 Stadium