The pilots of the World Airways DC10 that skidded off a slippery runway into Boston Harbor last month while landing at Logan International Airport expressed no special concern as they prepared to land, a tape from the jet's cockpit voice recorder suggests.

But 11 seconds after touching down, as the plane barreled along the runway at 130 mph, pilot Peter J. Langley said: "No braking." Federal safety investigators are trying to establish if the runway was more slippery than the crew had understood from weather broadcasts.

Despite braking problems, the plane slowed, as the pilots apparently used reverse thrust and "spoilers," flaps atop the wing that increase drag. Twenty-five seconds after touchdown, with co-pilot Donald C. Hertzfeldt calling out decreasing speeds, Langley cried: "No braking. Oh, deleted ."

With speed below 70 mph, Langley said: "We're going off the end." Co-pilot Hertzfeldt then radioed a distress call to the airport tower: "World's going off the end."

The wide-bodied jet plowed into shallow salt water beyond the 10,000-foot runway. The plane's fuselage snapped in two just behind the cockpit. One hundred ninety-six passengers and all 12 crew members scrambled to safety, but two passengers are missing and presumed drowned.

Yesterday, the National Transportation Safety Board, which is heading the investigation, released the tape transcript. It offers no dramatic clues to the cause of the Jan. 23 accident.

Investigators are still trying to establish whether the plane touched down too close to the end of the runway, as is commonly suspected when airplanes go off the end.

The tape transcript shows that 25 minutes before landing a controller asked the crew whether it had monitored automatic weather broadcasts about conditions at Logan, which said that "braking action is fair to poor" and advised pilots to "use caution." Hertzfeldt responded: "Affirmative."

Transcripts of the tower's conversations with planes that landed before the World jet suggest that some pilots felt conditions were worse than that. "If nobody else told you--they probably have--it's poor to nil out there on the braking," a Delta Air Lines pilot told the tower.

However, the pilots of the World Airways flight got no further advice on runway conditions from controllers in the tower.

The DC10 did get repeated directions to turn and and descend as it neared Logan. At one point, Hertzfeldt remarked: "Seems like a lot of grinding around for not much traffic." Pilot Langley responded, "Uh, huh."

"They always seem to do this, yeah...," Langley continued. "I've never landed on this runway." Hertzfeldt answered: "I landed here once."

After receiving clearance to land, the crew conducted what appears to have been a normal pre-landing checklist. Hertzfeldt suggested corrections to the approach path, then called out altitudes remaining before touchdown.