IRVING, Texas (AP) _ A week of testimony about what led to the crash of a Delta Air Lines jet on its landing approach covered factors from dinner breaks and shift changes in the control tower to improperly set radar and a storm's sudden appearance.

But it will be months before an official ruling closes the case.

Winston Lee, a Florida landscape architect whose wife was one of the flight attendants killed in the Aug. 2 crash, said he hopes people will stop ''tail- covering and finger-pointing'' and learn from the tragedy.

Several witnesses at the four-day National Transportation Safety Board hearing, which ended Friday, described how Flight 191, a Lockheed L-1011, emerged from a sudden storm and crashed, killing 137 people.

Gene Skipworth, an air traffic control supervisor, said Flight 191 came out from from a bank of clouds in what appeared to be level flight.

''It just didn't look right to me,'' he said. ''The nose is usually up slightly. It was instant; I said 'Go around.'''

But his command came too late. The jet had already touched down in a field north of the airport and bounced, clipping cars on Texas Highway 114.

''After the 'go around' I saw fire in the left wing and the plane made a sharp left turn, winged down, nosed down, bounced into water tanks and exploded,'' he said.

Wind shear, an abrupt change in wind direction and velocity during thunderstorms that can rob a plane's wings of lift and press the craft downward, has been cited as a major factor in the crash.

But still in question, and the subject of nearly 40 hours of testimony from 32 witnesses, is why pilot Ted Connors wasn't warned he was about to fly into an area of potential wind shear.

Witnesses testified that three positions in the airport's control tower were changed in four minutes just before the plane went down, either because of shift changes or dinner breaks.

Richard Douglass, a National Weather Service meteorologist, said he left his radar unmonitored for 45 minutes while he ate dinner. He returned shortly after the crash.

A Federal Aviation Administration controller didn't realize his radar scope had been set to filter out indications of minor rain storms - which is how the storm looked until seconds before the crash.

Delta policy is that its pilots never fly into thunderstorms, but witnesses spent hours debating whether what Flight 191 entered was actually a thunderstorm.

Skipworth said he had seen lightning, but added: ''Unless I'm sadly mistaken, seeing one flash of lightning does not mean it was a thunderstorm.''

Weather service employees spent nearly two days explaining that the storm popped out of nowhere from a weather system that looked unthreatening and uninteresting just minutes before.

Jack Williams, chief weather service meteorologist for Fort Worth, defended his decision not to issue a severe-weather warning, saying none of the data the service gathered on scattered rainstorms in the area suggested anything as strong as what buffeted Delta 191.

According to testimony, the last weather report that the pilots apparently received was of gusts of up to 15 mph. But minutes later wind topping 50 mph whipped south across the airport along with sheets of rain.

Technology to warn of wind shear, caused by microbursts or masses of cold air pouring out of thunderstorms like water from a faucet, is still in its infancy, witnesses said.

Like 60 other airports, Dallas-Fort Worth has a Low-Level Wind Shear Alert System, but it didn't sound an alarm until the storm reached the airport property, after Delta 191 crashed.

The key words to preventing a recurrence of such a crash are ''avoid, avoid, avoid'' severe weather cells, FAA official Cliff Hay said Friday.

William Smith, a former Lockheed engineering pilot now working for an insurance company probing the crash, testified Thursday that few pilots could have pulled out of the turbulent wind conditions that contributed to the crash.

But in an interview outside the hearing, Richard Bray, an aerospace engineer for NASA, said two pullouts were attempted, both in the six seconds before impact. He said data showed ''the aircraft would have missed the ground'' if the pilot had sustained the first pullup.

NTSB Chairman Jim Burnett said at the hearings' outset on Tuesday that they weren't meant to finger a culprit. And it will take months to reach a conclusion, he said.

''Neither I nor any other board personnel will attempt to analyze the facts or announce a probable cause at the close of this hearing,'' he said.

That didn't soothe Lee, the flight attendant's husband.

''How many more crashes will it take before they do something?'' he asked. ''Sometimes I wanted to stand up and scream, 'You're forgetting your purpose here.''' About 25 lawsuits already have been filed in Florida, where many of the passengers lived, and in New York and Texas. A federal court panel will consider a motion Nov. 21 to consolidate the cases before one judge.