* Investigation has yet to reveal cause of accident
* Aviation Ministry audit says Dana planes are airworthy
By Joe Brock
ABUJA, Jan 4 (Reuters) - Nigeria's Dana Air resumed flights on Friday, seven months after one of its planes crashed into a Lagos apartment block, killing 163 people in the country's worst airline disaster in two decades.
The government lifted a ban on the airline in September but an investigation is ongoing and there is still no official explanation of the crash.
Dana Air's five remaining McDonnell Douglas MD-83's operating in Nigeria have a capacity of 140.
Airline spokesman Tony Usidamen said 67 passengers were on board the resumed Lagos-Abuja flight on Friday and 82 on the return journey.
"There was a round of applause for the very smooth landing," Usidamen said by telephone.
Tickets were sold for as little as 14,400 naira ($92) one way, around half what some airlines are charging. Dana Air will only be flying the Lagos-Abuja route for the time being.
The MD-83 crashed in a Lagos suburb on June 3, killing everyone on board and 10 people on the ground.
The pilot reported dual engine failure before the plane went down.
"We won't know the cause until the investigation has been completed," Aviation Ministry spokesman Joe Obi said. "A thorough audit of the airline has been done and the remaining fleet is airworthy."
Air crashes are relatively common in Nigeria, which despite being Africa's second biggest economy has a poor air safety record, although it had improved in the years before the Dana crash.
Even so, air travel remains the quickest and often safest way to travel across a country nearly twice the size of Spain with a dangerous and dilapidated road network.
International carrier Air Nigeria, formerly part of Richard Branson's Virgin fleet, shut down in September due to what it called "staff disloyalty and environmental challenges".