Analysis of information sources in references of the Wikipedia article "McDonnell Douglas DC-9" in English language version.
The noise reductions relative to the hardwall JT8D-9 were 8.2 EPNdB for takeoff with cutback and 8.7 EPNdB for landing approach.
The last time an aircraft skidded off the runway in Toronto, seriously injuring passengers, was more than a quarter-century ago. On June 26, 1978, an Air Canada DC-9 skidded off a taxi strip at Toronto International Airport (what is today Pearson International Airport) during an aborted takeoff, then belly-flopped into a swampy ravine, killing two passengers and injuring more than a hundred others.[dead link]