WASHINGTON — The Federal Aviation Administration on Friday proposed fining Boeing $13.5 million for failing to meet a deadline to provide airlines with instructions on how to prevent fuel tank explosions like the one that destroyed TWA Flight 800 off the coast of Long Island, N.Y., 16 years ago, killing all 230 people on board.

The fine underscores the difficulty the agency has had prodding the industry to comply with important safety regulations that can be complex or expensive to implement.

In July 2008, then-Transportation Secretary Mary Peters held a news conference to celebrate new regulations aimed at preventing another tragedy like the one in 1996, when a fuel tank on the Boeing 747 exploded minutes after takeoff from JFK Airport.

Four years later, not only has Boeing been late in meeting those regulations, but airlines are balking at making some of the aircraft fixes they’re required to make.

Boeing Co. spokesman Miles Kotay said the aircraft maker ‘‘has made pioneering efforts in the complex process of developing and certifying the fuel-tank inerting systems at issue and is committed to continuing those efforts.’’