An investigator into the Jan. 30 crash of a Cape Air plane in the state forest this week released the transcript of the dialogue between the pilot and air traffic controllers. It is still unknown what caused the airplane crash that seriously injured both the pilot and passenger.

Steven Demko, an investigator for the National Transportation Safety Board, said this week that there was nothing in the conversation between the pilot and approach control that suggested there was any trouble on the plane. "About three minutes prior to the crash, the pilot reported on the common traffic frequency. He reported he was seven miles out on the ILS 24, which is the approach. Approximately one and a half minutes later, we hear a series of mike clicks, the keying of the frequency, which is consistent with turning on runway approach lights. Then just prior to the accident, by 13 seconds, he reports he is three miles out from 24."

Mr. Demko said: "No further transmissions were recorded."

The plane went down at approximately 6:30 p.m. The plane, Cape Air flight No. 1381, was bound from Providence to the Vineyard when it crashed in a wooded area east of Runway 24.

Mr. Demko said there is no information to suggest any reason for the crash. Because of the severe injuries to the pilot, he has not yet been interviewed. Mr. Demko said following normal practices, he has requested all background information about the pilot and the plane.

Sharon Stevens-Grunden of Oak Bluffs, the passenger on the plane, returned home from Martha's Vineyard Hospital earlier this week. David Grunden, her husband, said his wife is recovering slowly. "She is improving. It will be two or three weeks before she can do anything for herself." She suffered severe burns to the hands and face.

The pilot, Mark Trafton, 40, of Westport, remains in critical condition at Massachusetts General Hospital in Boston, suffering from severe burns. Mr. Trafton is credited for having helped Mrs. Stevens-Grunden out of the plane after the crash. He also called 911 for help using a cellular telephone.

Airport manager William Weibrecht said the Cessna 402 plane was taken off-Island in a container last Friday and will be stored in Plymouth. The two engines were taken off-Island earlier for study.

Mr. Weibrecht said: "The investigators have access to the plane to further their work. It is not likely they will reconstruct it."

Mr. Weibrecht said there appears to be nothing wrong with the airport systems, although he said: "We definitely are evaluating upgrades and improvements." Last October, four people were killed in a private plane that crashed in the state forest, not far from the eastern end of Runway 24 or last month's crash.

Mr. Weibrecht is looking at ways to make the airport even safer than it is now. He said he is pushing to have the FAA tower at the airport remain open later in the day. Traffic control hours in winter are daily from 7 a.m. to 5 p.m. In May the hours go from 6 a.m. to 10 p.m. "We are looking to have the tower open at least as long as there is airline service. The last flight now is 8:15 p.m.," he said.

Mr. Demko said the preliminary results of the crash won't be available until the end of the week.