LaGuardia Airport’s failure to put communication transponders on emergency vehicles played a role in a fatal runway collision between an Air Canada passenger jet and an airport fire truck, according to a preliminary report the National Transportation Safety Board issued on Thursday.

The air traffic controller who allowed the fire truck to cross the runway even as the jet was approaching for a landing on March 22 had been juggling air and ground traffic leading up to the collision, the report says. And it details how the firefighters driving that truck, the lead vehicle in a convoy responding to an issue with another plane, failed to immediately understand that instructions they heard over the control tower frequency radio to “stop, stop, stop” were meant for them.

But the report focuses in particular on the lack of transponders in the emergency vehicles, which investigators suggested could have allowed an automatic warning system to alert the controller that the plane and the vehicles were on a potential crash course.

Without the transponders, the “system could not uniquely identify each of the seven responding vehicles or reliably determine their positions, or tracks,” investigators wrote in the report. “As a result, the system was unable to correlate the track of the airplane with the track of Truck 1” — the truck that was struck by the plane. Thus, the report added, the system “did not predict a potential conflict with the landing airplane.”

The Federal Aviation Administration recommended last year that airports outfit their emergency vehicles with such technology to avoid close calls. On Thursday, before the report was released, Kathryn Garcia, executive director of the Port Authority of New York and New Jersey, told reporters that the agency would wait to see the report before making any changes. The Port Authority operates the three major airports in the New York area, including LaGuardia.

The 15-page report offers the most comprehensive presentation the N.T.S.B. has issued detailing the factors that led to the March 22 collision, but it is still preliminary, and the board has yet to reach a conclusion about what caused the accident. Similar investigations usually take about a year.

Still, the report did answer some key questions about the first deadly accident at LaGuardia in more than three decades. That included what role air traffic controllers played that night and what the people in the fire truck heard before the collision. The accident killed both pilots of Air Canada Flight 8646 and sent 39 passengers, as well as the two firefighters in the truck, to hospitals.

The report details how the convoy of emergency vehicles, which was responding to a separate incident involving a United Airlines plane, made multiple attempts to contact the air traffic control tower to seek permission to cross the runway. The attempts began more than 90 seconds before the collision.

Truck 1 had not been the intended lead vehicle in the convoy. Originally, a tool truck that went by the call sign Truck 7 was in front. But Truck 7’s first attempt to reach the tower was blocked by other radio communications. After a second attempt, its drivers switched places with Truck 1, which took over the lead position and, with it, responsibility for making contact with air traffic control.

In the tower, two controllers were on duty, as is standard for the overnight shift at LaGuardia. But according to the report, in the minutes leading up to the collision, only one controller was managing both the airplanes and the ground vehicles. The second controller had been helping the United Airlines plane find its way back to a gate.

About 20 seconds before the collision, according to the report, Truck 1 got permission from air traffic control to cross Runway 4, along with the rest of the convoy. At that moment, the Air Canada jet was in the final seconds of its descent toward the runway and only 130 feet above the ground, according to the N.T.S.B.’s report.

Seconds after that, the controller began urgently calling on the fire truck to “Stop, Truck 1, stop!” But the truck did not stop. According to the report, it accelerated.

Farther back in the convoy, the driver of Truck 7 — the tool truck that was originally intended to be the lead vehicle — heard the controller’s command. Seconds later, she saw the oncoming plane and called “stop, stop, stop” to the drivers of Truck 1, according to the report. There are no recordings of the communications between the emergency vehicles, investigators said.

The fire truck’s turret operator recalled hearing an order to “stop, stop, stop” on the tower frequency, but did not initially realize that it was intended for his vehicle, according to interviews conducted by investigators. It clicked when he heard “Truck 1, stop stop stop,” but at that point, the vehicle had already entered the runway.

The report said that in the moments before the crash, the fire truck turned left — away from the oncoming plane. But it was not enough to avoid impact.

Mayor Zohran Mamdani is floating a plan to delay payments into New York City’s municipal pension funds — his latest effort to stave off service cuts and a property tax increase as he grapples with a multibillion-dollar budget gap.

The plan, which the mayor’s team has presented to the administration of Gov. Kathy Hochul, could save the city at least $1 billion in the upcoming fiscal year, according to a person familiar with the discussions, and would be unlikely to affect pension payments for current retirees.

Mr. Mamdani’s team said it has yet to iron out the details. Any cost-cutting plan would most likely involve extending the deadline for the city to meet its long-term pension obligations beyond 2032, when it is scheduled to be up-to-date on its payments.

“While our administration has not yet put forward a specific proposal, we are actively assessing options for pension amortization,” Mr. Mamdani’s spokesman, Joe Calvello, said.

Similar proposals have drawn opposition from unions and fiscal watchdogs, with one leading budget expert warning they merely delay the city’s fiscal responsibility to avoid meaningful reductions in spending.

“The city is on a path to correct past fiscal mistakes and properly fund its pension obligations,” said Andrew Rein, president of the Citizens Budget Commission, a watchdog group. “It shouldn’t reverse course and stretch this out and make our children pay even more of our bills.”

One iteration of this proposal, presented this month by Julie Menin, speaker of the City Council, projected more than $1.2 billion in savings annually. An effort pushed unsuccessfully by former Mayor Eric Adams last year would have reduced costs by an estimated $1.3 billion in its first year.

Any delay to pension payments would need the approval of Ms. Hochul, who declined to comment.

Pension payments present a continuing liability for the city, which has a large unionized work force that has historically negotiated attractive retirement packages. The city’s total obligation to the five municipal pension systems for existing benefits, through 2032, amounts to $38.9 billion, according to data from the Citizens Budget Commission.

In 2013, under then-Mayor Michael R. Bloomberg and Gov. Andrew M. Cuomo, the city reformed its mandated pension payments following a drop in the assumed rate of return to 7 percent from 8 percent. That reduction meant the city had to pay more money upfront, creating a roughly $60 billion unfunded mandate. To address that, city and state leaders agreed to stretch out payments for future bills through 2032, at which point the added obligation was expected to be paid off.

The costs related to that change account for more than half of the city’s $10.5 billion pension expense this year, according to Ms. Menin’s office — a liability that is likely to grow.

Further delaying pension payments would significantly help Mr. Mamdani as he grapples with a $5.4 billion deficit through June 2027, which he has sought to reverse with risky and unpopular proposals, like raiding the city’s reserves and raising property taxes. He is also pushing Ms. Hochul to increase income taxes on wealthy residents, a proposal that is popular among Democratic state lawmakers but unlikely to get her backing. And he is asking her for more state aid to plug the hole as he navigates his first budget as mayor.

He is expecting to cut $1.3 billion from the current deficit by not expanding a housing voucher program and delaying, with Ms. Hochul’s blessing, a requirement to reduce school class sizes.

The plan backed by Mr. Adams, which Ms. Hochul tried to advance last year, ran into opposition from unions. Officials representing the pension fund for the United Federation of Teachers specifically raised flags about the Adams administration’s ability to carry out the plan, given concerns about the competency of the mayor, who was then under indictment, according to someone familiar with the matter.

Mr. Calvello said that the options being discussed were “distinct from the approach previously advanced by the Adams administration.”

Presidents of the city’s largest public-sector unions, Henry Garrido of District Council 37 and Michael Mulgrew of the teachers’ union, declined to comment on this development.

Mr. Rein urged city officials to consider other approaches to addressing the budget crisis.

“The city’s fiscal problem is a self-inflicted spending affordability crisis,” he said. “The best way to deal with that is to increase spending that works but eliminate spending that doesn’t improve New Yorkers’ life.”

A spokesman for Ms. Menin said she would review the mayor’s proposal when it reaches her desk. She is responsible for negotiating the city’s $127 billion budget with the mayor before it takes effect on July 1.

Mark Levine, the city’s comptroller, called Mr. Mamdani’s nascent proposal “a prudent step.”

“But the once-in-a-generation short-term savings this generates must be used wisely,” Mr. Levine added, “both to support the civil servants who pay into the system and to strengthen the city’s resilience against future fiscal and economic shocks, not as a way to avoid addressing our structural budget challenges.”

The father of an infant who was killed earlier this month when a stray bullet struck her was the target of the shooter, the police said on Tuesday.

The infant, Kaori Patterson-Moore, was sitting in a stroller near her parents, outside a deli in the Williamsburg neighborhood of Brooklyn on April 1, when two men on a motorbike sped up to the corner of Humboldt and Moore Streets, according to the police.

One of the men, who the police later identified as Amuri Greene, 21, fired shots into a crowd of adults and children, striking the baby and her 2-year-old brother, who was grazed in the back. The men then sped off as the baby’s father, Jamari Patterson, began screaming and picked up his lifeless child, according to witnesses. The two men have been arrested and charged with murder in the death of the 7-month-old girl. Both have pleaded not guilty.

Mr. Greene, who was caught that day, later told the police that he had wanted to shoot Mr. Patterson, a gang rival who he said had shot at him the day before, said Joseph Kenny, the chief of detectives for the New York Police Department.

Chief Kenny said the detectives had not recovered any evidence that Mr. Patterson tried to shoot Mr. Greene the day before his daughter was killed.

“There is no indication that it even took place,” Chief Kenny said.

The two men, Mr. Greene and the driver of the motorbike, Mathew Rodriguez, 18, “went out with purpose” to Williamsburg that day, Chief Kenny said. “They went out there to take a life.”

Both men were arraigned earlier this month on several charges including murder. Mr. Rodriguez fled after the shooting to rural Pennsylvania where he was with family and was caught two days later by the police in Barrett Township, two hours northwest of Williamsburg near the Pocono Mountains.

Just before his arraignment, as he was led to a police vehicle, Mr. Rodriguez wept and insisted he did not know Mr. Greene had planned to shoot at the crowd.

“I promise I didn’t know,” Mr. Rodriguez yelled at reporters. “I didn’t know it was going to happen.”

The two gangs have been targeting each other for years, committing acts of violence to settle grievances that arise out of social media posts, including rap songs that threaten and taunt each other, Chief Kenny said.

The feuds, like many that the police say drive gang violence in the city, are based more on historical tensions over geography, with groups of people shooting at one another because they live in different neighborhoods or housing projects.

“Historically, there would be gang wars over territory for drugs, territory for prostitution, money making, credit card fraud,” Chief Kenny said. The more recent feuds come “down to them simply disrespecting each other during these rap videos,” he added. “It’s geography. It’s development versus development.”

Right after the arrest, Mr. Greene waived his Miranda rights and confessed he was the shooter, Chief Kenny said.

The shooting, during daylight hours on a busy Brooklyn street, stunned city officials and residents of the neighborhood.

A large crowd, including Attorney General Letitia James, Representative Nydia Velazquez and Public Advocate Jumaane Williams, appeared at a vigil earlier this month for the baby.

“My family is broken, I am broken,” said Arlene Poitier, the baby’s great-grandmother. “I don’t have her to sleep with me at night anymore.”

A makeshift memorial had been set up outside the deli, where the sidewalk was festooned with dozens of colorful votive candles, mylar balloons and oversized stuffed animals.

Nestled among the keepsakes was a photo collage of Kaori and two posters that read, “Don’t Shoot. I Want To Grow Up.”

Nate Schweber contributed reporting.