Embattled Marine Official Retiring Early : Military: Former chief of staff of the El Toro base will avoid threat of court-martial and retain medical benefits. Another officer killed himself amid allegations they took Corps aircraft for personal use.

The former chief of staff at the Marine Corps Air Station here plans to retire early on March 1 to avoid the threat of a court-martial and hold onto medical benefits for his wife, who is suffering from a brain tumor, his son said Wednesday.

“It’s not a question of was my father guilty--everyone knows that he was not,” said Joseph Underwood IV, son of Col. Joseph Underwood, 51. “My father couldn’t risk the insurance on my mother because the doctors’ bills are so high . . .

“My father just couldn’t risk doing that so that’s why he backed down. And I’ve never seen my father back down to anyone before,” he said.

Joseph Underwood and Col. James Sabow, also 51, his close friend and deputy in charge of air operations at the base, were relieved of their posts last month amid allegations that they used Marine planes for golfing jaunts and other personal trips.

Sabow, a 28-year career Marine with a wife and two children, killed himself Jan. 22 with a shotgun on the patio of his base home, authorities said.

Underwood’s retirement would seem to allow a quiet ending to a scandal that rocked the Marine base here last month, even as people have been preoccupied with the fate of more than 5,000 fellow personnel from the El Toro-based 3rd Marine Aircraft Wing now deployed in the Persian Gulf.

With 29 years in the service, Underwood would ordinarily have come up for the standard three-decade retirement later this year. But the war has meant that many career service members are staying in longer, and Marine officials close to his case said Underwood would likely have been expected to stay on indefinitely were it not for the scandal.

El Toro spokeswoman Capt. Betsy Sweatt said she could not say when Underwood would be retiring and added that the investigation into his actions is continuing.

But a source at El Toro headquarters confirmed that Underwood is listed to go into “separations” this month--an administrative processing section for Marines who are about to leave the Corps--and is then on internal leave from Feb. 15 to March 1.

Maj. Walter Bansley at Camp Pendleton, defense counsel for Underwood, refused comment on the status of the case, citing orders from superiors.

Underwood himself, who has maintained in past interviews that he did nothing wrong as chief of staff, could not be reached for comment this week. His son, 21, who lives in Houston, said his father was resting with relatives in Florida.

The colonel’s son said he understood that investigators were looking at one trip to Arizona by his father in which he took along a friend and former Marine reservist who was going to be reactivated into the Corps.

Sources told The Times previously that the investigation centered on allegations that Underwood and Sabow used base C-12 Beechcraft planes to go on golfing trips to the East Coast as well as Nevada and elsewhere in the Southwest.

The younger Underwood maintained, as has his father, that the colonel used the plane to get in enough hours to keep his flight status active and that any golfing he may have done at his destinations was purely secondary.

Speaking with bitterness and anger, the younger Underwood said: “This whole thing is absolutely ludicrous. . . . This is a raw deal.”

He said he could not discuss some specifics of the retirement but understood from his father that he had agreed in talks with the inspector general’s office to leave the military so that the investigation against him would not be pursued, thus avoiding the prospect of a court-martial or other prosecution.

A court-martial or lesser punishment for improprieties could expose him to the loss of military benefits and family insurance. Jean Underwood, the colonel’s wife, has been suffering for several years from a brain tumor, according to her and her family.

In contrast, “if you retire with the proper number of years in, you get all the benefits,” confirmed a legal officer with the Marines, who asked not to be identified. “The 20-year mark is what one usually needs, and it goes up with the years past that.”

“What’s the sense fighting this whole thing if you’re on your way out of the Marines anyway in a matter of months?” asked another Marine official close to the case, also requesting anonymity.

A colonel with Underwood’s tenure makes more than $63,000 a year, plus $250 a month in flight pay and variable allowances for quarters and subsistence. With his length of service, he could expect to retain just under 75% of his salary in retirement pay, officials said.

Underwood had served as chief of staff at El Toro since 1987, second-in-charge to the base general and overseeing everything from meals and bunks to flight time and training facilities.

“This decision was made for my father,” the younger Underwood said of the departure. “It would have meant a lot to him to have had a big retirement as chief of staff at El Toro, but now he has to just shrug this off and walk away. . . .

“He didn’t want to jeopardize my mom’s benefits,” he added. “He loves my mom too much. . . . So he had to bite his pride.”