UPDATE 3-WestJet says 2nd quarter revenue pressured, shares down
* Revenue per available seat mile to decline in Q2
* Sees smaller rise in cost per available seat mile in 2013
* Will buy 10 Boeing 737-800s, sell 10 737-700s
* First-quarter earnings/share C$0.68 vs C$0.63 estimate (Adds details of outlook, buy-side comment, closing stock price)
May 7 (Reuters) - Shares of WestJet Airlines Ltd, Canada's second-largest airline, fell as much as 13 percent on Tuesday after it warned it was likely to earn less revenue from every seat in the coming quarter, partly due to softer demand.
The company, based in Calgary, Alberta, said second-quarter revenue per available seat mile (RASM), a key measure of an airlines' efficiency, was likely to decline moderately.
It partly attributed that to the Easter and Passover holidays, which traditionally bring higher passenger numbers, falling within the first quarter this year.
"You're seeing capacity in Canadian airlines starting to increase. Obviously that puts downward pressure on ticket prices. So the revenue per available seat mile goes down," said Luciano Orengo, a portfolio manager with Manulife Asset Management, who owns WestJet shares.
WestJet also said its aircraft were less full in April, falling 3.5 percentage points on the year to 82.7 percent. RBC Capital Markets analyst Walter Spracklin called the traffic data results "negative" because WestJet's capacity growth of 7.4 percent far exceeded demand growth of 3.2 percent. Continued...