LAGOS, Nigeria (AP) —Documents on three deadly jetliner crashes in Nigeria, including one in which a plane filled with children going home for Christmas burst into flames, offer a harrowing look at the loosely enforced safety regulations and oversight in Africa’s most populous nation.

The records obtained by The Associated Press show that the captain of another Nigerian flight that crashed had gone back to work as a pilot despite being shot in the head years before. And, in another case, a pilots’ manual included blank pages instead of key safety information.

Nigeria’s government long has declined to release formal records surrounding three fatal crashes in 2005-2006, including the one that killed scores of children.

While none of the airlines involved in the three crashes still fly in Nigeria, the safety concerns come after the West African nation gained a coveted U.S. safety status last year that allows its domestic carriers to fly directly to America.

The AP requested the documents about the crashes through a Freedom of Information Act request to the U.S. Federal Aviation Administration. The U.S. became involved in those inquiries because the planes were manufactured by U.S. companies and because Nigeria requested the help of American investigators.

Though officials now say air travel is much safer, the documents add to worries about flights in Nigeria, a nation of more than 160 million people where graft and incompetence often dominate government and where the demand for air travel has spiked over the last five years.

Nigerian officials have offered conflicting reasons for the three major crashes in 2005-2006, never releasing full reports on what happened.

A 2009 study done for the World Bank concluded the aviation authority spends more than 90 percent of its budget on salaries and cannot fund training or equipment needs.

The authority “is still struggling to enforce quality, safety, and security standards on federal agencies operating Nigeria’s airport and airspace systems,” the study said.

Demuren, the authority’s director general, acknowledges that challenges remain for his agency as it has an aging work force and old equipment but he insists things have improved greatly.