Firstly, let's have a look what's on Air China's official web site!
Air China's Crew Operation Department has enjoyed a perfect safety record ever since it was founded in 1955. Source: http://www.airchina.com.cn/caworld/e_caworld.html
Secondly, Airsicknessbag (Daniel), thanks for the web address (http://aviation-safety.net/database/1990/900322-0.htm
) you have mentioned above. However, I was unable to find any information about that accident. I don't know where they got the details, because there wasn't anything about it from some most powerful aviation database in China and the database powered by National Transportation Safety Board of USA! Until now, I am still not too sure is that true or not, because no-one can prove it, except the above hyperlink!
Thirdly, just want to answer something, although Air China officially established in 1988, but its crew operation department (CAAC Beijing Bureau) established in 1955 and it was operated independently.
Fourthly, no-one could deny that Air China had a safety record up to 47 years and it has been officially proved by China, IATA and all other civil aviation organizations around the world, and all media entities fully reckon that there is nothing wrong with the safety record, because it is the truth and fact!