A 36-year veteran of the D.C. fire department died of a massive heart attack yesterday morning, just before he was to undergo surgery for a knee injury suffered when he was knocked down by a pit bull terrier while responding to a fire call Wednesday in Northwest Washington, fire officials said.

Costello N. "Robbie" Robinson, believed to be the department's oldest active firefighter at age 64, died at Washington Hospital Center, fire officials said. The D.C. medical examiner's office, which is looking into the death, could not be reached for comment.

Robinson, known to his co-workers as "Colonel," was the third D.C. firefighter to die in the last two months. Two firefighters, Louis J. Matthews and Anthony Phillips, were fatally injured fighting a Fort Lincoln town house fire May 30; a third firefighter injured in that blaze, Joseph Morgan Jr., remains in critical condition at Washington Hospital Center.

Robinson, a technician who drove a firetruck and made preliminary assessments at fire scenes, and his platoon at Engine Company 2 responded to a call on Temple Court NW at 12:41 p.m. Wednesday, fire officials said. While searching an alley where smoke was reported, Robinson was attacked by a pit bull.

He wasn't seriously injured by the dog, but he tore a ligament in his right knee trying to elude the animal, officials said. A fire official close to Robinson's family said yesterday that Robinson had previously injured the knee in 1981.

The fire department maintained yesterday that Robinson did not suffer any dog bites, but while bathing him at the hospital on Thursday, Shirley Robinson noticed marks on her husband's body, and her husband told her that he might have been bitten.

Robinson died at 5:15 a.m. yesterday, said Marianne Worley, a hospital spokeswoman. He had been scheduled for knee surgery at 2 p.m.

His death shocked relatives and friends.

"I just had the confidence, you know, that he would be all right," said Shirley Robinson, 62, his wife of 42 years. She said they met as children in the Shaw neighborhood.

She said her husband had worked in a cafeteria at the National Institutes of Health before joining the fire department. He continued to work one or two 24-hour shifts a week until his death.

Fellow firefighters used to joke that Robinson had accumulated "4,000 hours of sick leave," said James Millar, a fire department chaplain. "He never took any. . . . He was a remarkable man."

Millar said he last spoke with Robinson early Thursday. "He was resting comfortably," Millar said. "He was most concerned about how long he'd be out of work."

Robinson was a colonel in the D.C. wing of the Civil Air Patrol, an Air Force auxiliary, said Col. Roland L. Butler, patrol wing commander. "He was caring, happy-go-lucky, all around a nice fellow."

Fire officials maintain that Robinson could effectively carry out the tasks assigned to him, but Imagene Stewart, a friend of Robinson's, said she was angry that he continued to be sent to fires.

"I couldn't understand it," she said. "At his age, he had no business out there with no pit bull."

D.C. police issued a citation to the dog's owner for letting it run loose, said fire Capt. Craig Dwyer.

Robinson is also survived by four children, nine grandchildren and a great-grandchild.

CAPTION: Costello N. Robinson