A dispatching error delayed the response of a second engine company to Saturday’s deadly five-alarm fire in Brooklyn, prompting the FDNY to launch an internal probe, department sources told The Post yesterday.

Dispatchers sent Engine Co. 248 to the blaze in the six-story apartment building on East 29th Street in Flatbush, not realizing the unit was already helping a cop who had accidentally shot himself at the 67th Precinct station house, right next door to its firehouse, the sources said.

Officials are trying to determine if the dispatchers mistakenly assigned Engine Co. 248 two jobs at once, or if the company members went to the police station on their own and delayed reporting it.

It was more than a minute before the company alerted dispatchers, who then had to scramble to find another company, the sources said.

While officials have said the biggest problems battling the blaze were 50-mph winds and an open door in the apartment where the fire began, they conceded the delayed response was significant.

“It did make a difference because they [Engine Co. 248] weren’t there to stretch a [water] line,” one source said.

But Brian Kuntz, president of the fire dispatchers union, insisted the company called in to say it was helping the injured cop just as it was given the fire assignment.

“It was simultaneous,” Kuntz said, adding that the reassignment occurred “immediately.”

An FDNY spokesman said the first units were on the scene within three minutes after the call came in, but they “never had a chance to extinguish the fire in the original apartment and it quickly spread.”

The second company on scene was 248’s replacement, Engine Co. 249, which got there in about 6½ minutes.

It took about nine hours to bring the inferno under control, and it killed 62-year-old retiree Mary Feagin. Twenty firefighters and 11 residents were injured.

Steven Cassidy, president of the Uniformed Firefighters Association, said budget cuts kept the blaze from being contained sooner, since the first three units to respond were each short a man.

He called the communications mishap a “red herring.”

FDNY officials said the decreased manpower “does not apply in this case” because the conditions were so intense.

(Source: NY Post)