Arrow Air will probably be suspended from Defense Department contracts worth $20 million while Canadian authorities investigate why one of the company's jetliners crashed in Gander, Newfoundland, last December, killing 248 U.S. soldiers, a senior Air Force official said yesterday.

Deputy Assistant Air Force Secretary Lloyd K. Mosemann II predicted the suspension after a House subcommittee passed a nonbinding resolution urging a halt to all Arrow Air contracts to transport U.S. military personnel overseas until the completion of investigations of the crash and alleged safety violations by the Miami-based airline.

Mosemann, leaving the subcommittee hearing, said that although the probe is likely to take nine months, "We will probably suspend them in the near term. We try to honor the will of Congress."

Secretary of the Air Force Russell A. Rourke issued a statement later saying that "no action has been taken today to reconsider the contract but that won't preclude us from taking action in the future if further information provides a reason for review."

An Arrow Air spokesman in Miami called the suspension plans "entirely inappropriate in the absence of any findings of guilt or any indications that Arrow was at fault in connection with the Gander crash."

Mosemann said the Air Force, which is responsible for overseas charters for military personnel, would have to consider other commercial carriers to replace Arrow Air, which has contracts to shuttle troops from U.S. bases to Iceland and Diego Garcia in the Indian Ocean several times weekly. Earlier at the hearing, he said a suspension would boost costs $3.5 million to cover service by an alternative, higher priced airline.

The hearing by the House Arms Services subcommittee on investigations focused on the Pentagon's decision last Friday to award a $7.6 million contract to Arrow Air despite the Dec. 12 crash of a DC8 carrying soldiers home for the holidays from peacekeeping duty in the Mideast.

Rep. Larry J. Hopkins (R-Ky.), who sponsored the resolution, asked a panel of Air Force witnesses "how in the name of decency, fairness and common sense" could the service sign a new contract with Arrow Air in light of continuing investigations of the Gander accident and the company's alleged pattern of safety violations in recent years.

Maj. Gen. William B. Overacker, Air Force deputy chief of staff for operations, testified that because the "jury was still out" on causes of the Gander crash, the service decided there were no "substantive reasons" to suspend Arrow Air.

"Once that decision was made, we awarded that contract to Arrow," he said.

Overacker said past spot checks by Air Force inspectors had not turned up safety problems in Arrow Air planes. Nor was the service informed by the Federal Aviation Administration of safety deficiencies reported to the FAA as early as March 1984 when an Arrow Air pilot complained of excessive flight hours and delays in repairs. The FAA monitors the military's commercial charters.

Mosemann told the subcommittee before its unanimous passage of the Hopkins resolution that if it "established a precedent for us of not doing business with an airline until the cause of the crash is known, you might find us not doing business with more companies than the one doing business here."