Alfred V. Jackson, who survived 10 helicopter crashes in Vietnam, and Richard F. Giguere, who wanted to be a pilot, should not have been together in D.C. police chopper June 5 over Southeast Washington last week.

But Jackson's regular partner had a doctor's appointment and Giguere had volunteered to fill in for a few hours. Shortly after 2 p.m., while directing a squad car to a suspected burglar in a lower Southeast neighborhood, Juno 5 crashed in the 700 block of Yuma St. SE.

Residents in the quiet street heard the sputtering police helicopter overhead and several saw it falling lower and lower until it smashed into three electric lines, struck a transformer pole and tumbled to the street.

Jackson, the 34-year-old pilot, and Giguere, 38, were killed. Federal investigators have not determined the cause of the crash.

"He (Jackson) loved to fly," said Sgt. William T. Avery, as he sat in a National Airport hangar, which is headquarters for the helicopter branch. Avery's silver police badge was wrapped in black tape, a symbol of mourning.

"We used to call him 'Juno Jack' because he was just great. He knew the city like the back of his hand. If he had someone in sight, he (the suspect) didn't get away," Avery recalled.

Jackson's keen tracking ability two weeks ago helped direct officers on the ground to a man suspected of being the long sought "robber jogger" of Southeast Washington.

His friends say Jackson loved helicopters. "We used to go to the hobby shop in Eastover Mall and Jackson would pick up a model of any one he could," said Eddie McCloud, a D.C. police officer and one of Jackson's closest friends. "He was trying to get all different kinds of helicopters. When a new one would come out, he would get it."

Jackson had built 17 model helicopters, according to friends and relatives. Some were models of the small two-seater Bell 47 choppers he flew for the police department, others were of the combat-equipped U.S. Army Huey helicopters he flew in Vietnam.

"He was shot down 10 times in Vietnam and he survived," said D.C. policeman Allen T. White, another close friend. "He made it each time over there, but when he went down over here . . ."

Born in Valdosta, Ga., Jackson joined the Army in April 1965 and served until 1971, according to his brother David. Shortly after his discharge he joined the D.C. police department and went to the helicopter branch in 1973.

Three years later, he began working the midnight shift at the National Airport hangar with his partner, Roger King.

King, who retired from the force last year, visited the hangar last week to help mourn the loss of his two former colleagues.

He recalled that on those long midnight shifts, he and Jackson had only one radio and very different musical tastes.

"I like country and western and he liked soul, so we agreed to allot one hour for my station, then one hour for his, then back to mine," King said.

Their dislike for each other's musical tastes was a standing joke between them. One night, King recalled, during the country-western hour, Jackson in mock desperation "cut the radio cord in 100 pieces with a pair of scissors and we just laughed."

But Jackson took his police work seriously. He wrote the observer's manual used by the helicopter unit. The manual outlines the procedure for directing a pilot in pursuit of a suspect, a fellow officer said.

In his off-duty hours, Jackson visited Southeast public schools and spoke to students about juvenile crime as part of a community service program organized by Breaker 23, a club of Southeast residents he formed with White and McCloud, which now has more than 50 members, McCloud said.

Jackson lived with his wife, Alicia, also a D.C. police officer, and their 23-month-old daughter Lisa in a Southeast townhouse the couple bought two months ago. Angela, 8, Jackson's daughter by a previous marriage would visit on weekends, a family member said.

Lt. John L. Hampton, chief of the helicopter unit, said last week that Giguere had requested the extra duty with Jackson.

"I told him it would be past his quitting time, but he said, "That's all right - I'll just call my wife and tell her I'll be a little late,," Hampton said.

A call to his wife was typical of Dick Giguere, who, according to several fellow officers, was known as "a very devoted husband and father."

"Whatever he did, he did with Ann," said Avery. "He never went out with the boys but always with Ann."

"His whole life centered around his family," said Thomas Hamlett, his partner.

On Fridays when Giguere came to pick up his paycheck he often brought his 6-year-old son Eric along on the drive from the family's townhouse in Woodbridge, Va. He was building Eric a large scale model of the World War II German Stuka dive bomber, Hamlett said.

Six or seven months ago Giguere borrowed money from the police department credit union to pay for lessons to become a licensed airplane pilot, Avery said, "but he used it instead for his family." Eventually, however, he hoped to become a helicopter pilot like Jackson.

At work, "he was very meticulous about how he looked. He was always sharp," Hamlett said. "His flying suit was pressed and creased, Even in the hangar his shoes were always shined."

Giguere brought the same attention to detail to his job as the unit's ground safety officer at the hangar, Avery said. Giguere's duties included making sure all fire extinguishers were filled, that no one smoked in the hangar and that the hangar floor was free of any hoses, the sergeant said.

He was also the unit's artist. He would sketch his fellow officers in the hangar and he prepared the covers for the unit's annual reports.

Born in brockton, Mass., Giguere joined the police department in 1970 and became an observer with the helicopter branch three years ago. He lived with his wife, his son and two daughters, Michell, 13, and Lynn, 12.

Jackson and Giguere were the first members of the close-knit, 9-year-old helicopter branch to lose their lives while on duty. CAPTION: Picture 1, Richard G. Giguere, with his wife Ann; Picture 2,Alfred V. Jackson, with his wife Alicia.