On Friday, “line number 86,” a Boeing-owned  787 Dreamliner built for LOT Polish Airlines took off for a test flight to “demonstrate that the new battery system performs as intended during normal and non-normal flight conditions.”

This was the second test flight of the aeroplane since Boeing unveiled its improvements designed to circumvent the potentially disastrous on board lithium-ion battery fires. The company said its fixes address more than 80 possible causes. “Possible Causes” because no one -Boeing, regulators, airlines knows what caused the fires.

The jet, carrying test equipment, nine crew and  two Federal Aviation Administration (FAA) officials, took off from the Boeing factory runway near Seattle and flew for just under two hours. The flight took the plane about 1100km (755 miles) along the Pacific Coast following almost the same route as the test flight last week.

Boeing said of the test flight “The crew reported that the certification demonstration plan was straightforward and the flight was uneventful,” This is good news but I am still nervous that the measures have only been tested on aircraft that have flown for less than two hours. How about a couple of seven hours flights. No one knows how the fires were caused. Are we sure that the result is safe?

The company has promised the data will be handed over to the FAA “in the coming days.”  U.S. Transportation Secretary Ray LaHood, who oversees the FAA, explained on Friday that while he believes Beomuigs battery fix is “a “good plan” to fix the battery, he wants to ensure the Dreamliner is safe before allowing the planes back in the air:  “when they complete the tests, they’ll give us the information and we’ll make a decision,”

There are four possible outcomes now:

1. the US Safety authorities are convinced and they allow the aeroplane to be flown, followed by their counterparts in India, Japan and Europe which have also grounded the plane may follow. Each plane will need to have the battery modifications made. This takes about three days. One assumes that launch customer ANA will be the first to have its jets updated. They, therefore could see their  787s flying within the month
2.  Regulators are cautious and restrict the plane from making long trips over water for three to six months until the battery system is proven in flight
3. the authorities are not convinced and ask Boeing for more work which means the planes wont be flying for several more months.  I wonder what Boeing’s back up plan is if this happens?
4. The worst case scenario is that the planes are approved and the battery system fails again. Again, whats the back up plan?