MINNEAPOLIS (AP) — Boeing Co. said it's still not clear when it will resume test flights for its new 787, and an executive said in an interview that he doesn't know if the plane's first delivery would be delayed once again.

Boeing has been flying six of the new 787s with a goal of getting certification to deliver the first one around mid-February. Those flights halted after the electrical fire forced an emergency landing Nov. 9.

"I will tell you that we don't have a lot of margin in the flight test program," Randy Tinseth, Boeing's chief of marketing for commercial airplanes, said in an interview at the company's Virginia office. "The airplane hasn't been flying for a week. We don't know when it will be resolved, so you can do the math," He said that the first delivery is still "nominally" scheduled for the mid-first quarter of 2011.

The schedule is being closely watched because the first plane's first delivery is more than two years late. The flight tests are necessary for the plane to be certified by the Federal Aviation Administration.

Boeing has said the fire started with a panel called the P100. That same type of panel would be present on a production 787, spokeswoman Lori Gunter said.

The electrical system is important on any plane, but even more so on the 787. The plane's center hydraulic system is driven by electric motors rather than air from the turbines, and overall the 787's system generates about twice as much electricity as other Boeing planes. Tinseth called it the world's first all-electric commercial airliner.

Boeing said it will soon replace the panel along with nearby insulation. The company said it is also repairing what it called "minor structural damage" from the fire. It said the repair would be made using standard repair procedures, but it doesn't know how long the repairs will take.

The fire lasted less than 30 seconds, and the plane would have had time to land at an airport safely from any point in a typical passenger flight, the company said.

The company said it must finish investigating the fire and decide if any design changes are necessary before test flights resume.

The plane with the electrical fire landed in Laredo, Texas. Boeing planned to return two other test planes to Seattle from South Dakota and California on Tuesday. The electronics bays on those planes have been inspected, and no testing will be performed during the flights, the company said.

"Before the electrical situation we had on the airplane flying into Laredo, we had seen really minimal changes required (because of) the flight testing program," Tinseth said. "Of course, we still have work to do."

Boeing shares fell 83 cents to close at $62.78, then rose 83 cents in aftermarket trading.