The manual was duly approved by the Nigerian Civil Aviation Authority despite containing the blank section.
"The deficiency in the operation manual would probably make it difficult for pilots to take appropriate decision on when to go or not to go in (an) adverse weather condition," the report said.
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.
In the five years since the ADC crash, Nigeria has not had another major commercial airplane crash, something the nation's leaders point to with pride. In August 2010, the U.S. announced it had given Nigeria the FAA's Category 1 status, its top safety rating that allows the nation's domestic carriers to fly directly to the U.S.
The Nigerian government said it also now has full radar coverage of the entire nation. However, in a nation where the state-run electricity company is in tatters, state power and diesel generators sometimes both fail at airports, making radar screens go blank.
Yet air travel has never been so popular in Nigeria, whose growing middle and business class rely on air travel to avoid the country's poorly maintained and dangerous roads. The country had nearly 14 million air passengers in 2009, according to a December study by Lagos-based Ciuci Consulting and Financial Derivatives Co.
The nation's largest carrier, Arik Air Ltd., soon will have a fleet of 40 aircraft, the study said.
Yet Arik, like the nation's seven other domestic carriers, faces increasing economic pressure from rising jet fuel costs in a nation that must import the majority of its fuel despite being Africa's top oil producer, said Fola Onasanya, an analyst at Ciuci Consulting.
Major maintenance must be done outside the country, as Nigeria does not have the manpower or capability to do it locally, Onasanya said. Government regulations and taxes also add additional burden on companies in a nation where airlines have scrimped on maintenance in the past to cut costs.
"There's always been that pressure," Onasanya said.
Associated Press writer Joan Lowy in Washington contributed to this report.
U.S. Federal Aviation Administration: http://www.faa.gov
Nigerian Civil Aviation Authority: http://www.ncaa.gov.ng
Jon Gambrell can be reached at www.twitter.com/jongambrellAP.