Legal Responsibility
The accident, since in occurred in France, will be covered under, that is, subject to French law. The contract between Airbus and Etihad may well have specific provisions concerning loss and responsibility; normally one would expect to see an arbitration clause given a buyer in the Middle East. The technicians, though, were from a different company.
Under French law, where a tort (a wrong) is committed a remedy exists. There are so-called 'force majeure' events for which no one is deemed to be responsible. In these cases, the insurance--probably Factory Mutual in the U.S., but maybe not--would 'simply' pay the loss.
But here it's possible that the technical company's employee's are at fault, especially if one of them fell on the pedestal; unless the fall was precipated by a tortious act of an Airbus employee. If Airbus can show that the accident was caused by one of the non-Airbus technical employees, i.e., the tests were finished when such an employee acted imprudently and fell on the pedestal--then the technical company will be responsible in whole or part for the loss. If the third-party technical personnel were merely observers and had nothing to do with the accident, then they would not be liable.
While it may seem that the fact the technicians were from a different company would shield Etihad, because of the theory of agency, these employees may be deemed to be under Etihad's control, and if they are, then Etihad may ultimately share some of the responsibility. Based on the 'facts' as they have been developed, at this point there's really no way to tell. In this regard, it's not uncommon in the Middle East to have employees "seconded" from one employer to another. If this was the case, it's possible that the technical case were "seconded" to Etihad, and thus, assimilated to Etihad employment.
There may be a good deal of finger-pointing down the line; the main thing, in order to determine tort liability, is to try to determine exactly what happened.