Questions about the cause of the April 29 Kailua helicopter crash won’t be answered for a long while, but the federal agency investigating it has reached one conclusion, well in advance: Rules governing tour helicopters need tightening up.

The accident, which killed a pilot and his two passengers when a Robinson R44 helicopter slammed into Oneawa Street, stunned the island. At that hour — 9:10 a.m. — a crash on this ordinarily busy residential street could have left many more casualties.

But it’s the confluence of multiple incidents, not just this single episode, that is driving the National Transportation Safety Board to bring tour operations under more safety rules governing other aircraft operations.

That is a wise impulse. This sector of the tourism industry has benefited from steadily increasing visitor counts in Hawaii, and it needs some measured oversight.

In addition to the Kailua tour copter, operated by Novictor Aviation LLC, the NTSB is currently investigating the midair collision of two floatplanes in Alaska this month, followed a week later by a crash of a Beaver floatplane.

The final analyses are not necessary before action is warranted, safety board Chairman Robert L. Sumwalt rightly observed in a prepared statement. Safety improvements have been sought urgently for some time, with recent accidents heavily underscoring that concern for the NTSB.

Tour flights of planes and helicopters, along with other categories, operate under a section of Federal Aviation Administration (FAA) regulations known as Part 135. It covers air medical service, air taxi, charter or on-demand flights and other operations.

Encouragingly, the safety board, an independent federal government investigative agency, recently has begun pressing its own improvement agenda. Specifically, it seeks to mandate that Part 135 operations have safety management systems that are not currently required.

According to proposals published and submitted to the FAA in December, such systems would include a flight data monitoring program.

Also part of the NTSB “Most Wanted List of Transportation Safety Improvements” is a bid for the development of “a cue-based training program for commercial air tour pilots in Hawaii” to address flight hazards and decision-making.

Once it’s developed, according to the publication, all commercial air tour operators in Hawaii would be required to provide the training to newly hired pilots.

The Kailua crash became the focus of public attention because of these safety concerns, but it’s only the latest development amid ongoing criticism from residents and elected officials over noise from overflights as well.

Some regulatory changes are en route already. Example: By Jan. 1, most commercial aircraft worldwide will have to be equipped with Automatic Dependent Surveillance-Broadcast gear that enable flight paths to be tracked through the Flightradar24 service (www.flightradar24.com).

But this would not extend to the neighbor islands, as the mandate doesn’t apply beyond 30 nautical miles from a federal list of major airports, which includes the Daniel K. Inouye International Airport. So further safeguards surely are justifiable.

For its part, an association of Hawaii helicopter tour pilots locally is working to respond to noise complaints. Although many diversions from a prescribed flight altitude of 1,500 feet are unavoidable due to airspace traffic patterns, responsiveness to the public remains critical.

So is public transparency. Hawaii’s congressional delegation is seeking more information from the FAA on the scope of air tour traffic and risks — disclosure that residents deserve to have.