News provided by FlightGlobal.com
28 January 2019 by Jon Hemmerdinger, Boston FlightGlobal.com
WestJet is making modifications to its Bombardier Q400 turboprop fleet to prevent an issue that has caused at least three recent in-flight Q400 depressurisations.
One of those incidents involved a WestJet Encore aircraft and two involved Porter Airlines‘ Q400s, and all three apparently stemmed from cargo door handles not being properly stowed.
“Bombardier has released a recommended modification to fix the issue,” WestJet tells FlightGlobal. “WestJet Encore is completing this modification to the fleet and to-date more than half of our fleet has been modified.”
WestJet‘s regional unit Encore operates 47 Q400s, according to Flight Fleets Analyzer.
“Although this was human error, it is a known issue on the Bombardier Q400,” WestJet adds. “Transport Canada has determined that there is no risk to safety and the decision to complete the modification is at each company’s discretion.”
WestJet declines to provide more details about Bombardier’s recommendations, such as when Bombardier issued them.
The Montreal airframer did not immediately respond to questions about the recommendations, but says three recent depressurisations involved cargo door “handles that were not stowed properly and popped open.”
“The door seal would deflate as if someone was opening the cargo door, as the system was designed,” Bombardier says. “No problems were noted with the door handle in any of these three cases.”
Transport Canada is “evaluating the situation. The department will not hesitate to take action should a safety concern be identified”, the regulator says.
The most recent in a string of similar events happened on 17 January and involved an Encore Q400 that had not yet undergone WestJet‘s modifications, the airline says.
“Flight 3265 from Calgary to Kelowna did experience a loss of pressure due to [an] incorrectly stowed door handle,” WestJet says.
During cruise, pilots of that Q400 (registration C-FWEP) received a “fuselage door warning light”, says the Transportation Safety Board of Canada’s daily aviation incident report. “Subsequently, a loud bang was heard and pressurisation was lost during the descent.”
After declaring an emergency and landing safely, maintenance personnel “found the lateral door handle in the extended position,” the TSB says. “The door handle had not been secured properly.”
That event followed two similar 2018 incidents involving PorterQ400s. In August last year a Porter Q400 depressurised at 4,000ft, and in October 2018 a Porter Q400 depressurised at 12,000ft, the TSB has reported.
“This situation occurs periodically, always during the climb stage of flight in our experience,” Porter told FlightGlobal last year. “It is considered to be primarily an operational and passenger inconvenience, but not a significant safety issue.”
“Our maintenance team will replace door handles, if deemed necessary, and door operation procedures for ground staff are consistently emphasised,” the airline added.
Bombardier adds that the “Q400 aircraft has been designed to be robust and reliable in consideration of the high-cycle demands of regional airlines, and was designed to comply or exceed all airworthiness certification requirements”.