Comments on: Bombardier Q400s Can’t Keep ‘Em Down When They Grow Old

By: Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER)

Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) — Mon, 24 Sep 2007 23:58:24 +0000

Murray

I have been following the Q400 accidents that occurred in Denmark and Lithuania very closely and consider these accidents to be very critical situations. These failures are giving the aircraft industry a subtle, but urgent warning that must be addressed. I found a report, dated September 15,2007 online re - Preliminary Report on Danish SAS Q400 accident that included a very useful drawing in analyzing the failure mode. It would also be very useful to review a drawing or sketch of the main landing gear retract/extend actuator, manufactured by the Goodrich Corp. in Tullahoma, Tennessee to confirm my analysis of these failures. Please note that a nose gear incident occurred in Japan in March, 2007, and I suspect that it probably contains a similar actuator design as the main landing gear system. If this is true, it would be very important to inspect the nose landing gear actuator as well as the main landing gear actuator. In my study of the main landing gear reports, they discuss the fact that the jam nut backed off and the lockwire was missing. Most of the hydraulic actuators used in the aircraft industry contain a locking device to prevent rotation of the actuator piston and are secured by a jam nut, and lockwired to prevent the jam nut and the locking device from backing off. This condition could eventually cause a disconnection of the rod end, which was actually stated in preliminary reports. This scenario may have actually occurred after 10,000 cycles and severe impact upon landing. I was surprised that no mention was made of the use of a locking device in the design of the main landing gear actuator.

By: The Cranky Flier » Q400 Problems Get Worse

The Cranky Flier » Q400 Problems Get Worse — Mon, 24 Sep 2007 14:52:09 +0000

[...] week I wrote about SAS’ two accidents involving landing gear problems on the Q400. This story keeps [...]

By: Zach

Zach — Fri, 14 Sep 2007 14:19:30 +0000

I believe I flew a Bangkok Air Q400 a couple of years back. Very quiet and comfortable for a turboprop. It feels more like a regional jet. Too bad they’re having issues.

By: CF

CF — Fri, 14 Sep 2007 04:02:32 +0000

Funny Well, hopefully you don’t have an odd number of takeoffs and landings - otherwise the number of cycles is probably the least of your worries! But if the plane is in midflight, I guess you could say it’s had half a cycle.

By: Bert

Bert — Fri, 14 Sep 2007 03:56:09 +0000

“(1 takeoff and 1 landing count as 1 cycle)”

Does only 1 takeoff or only 1 landing count as a half a cycle?

I have never been in the Q series but I have flown tons of DASH-8’s. Flying tanks! I bet someone was trying to save 2$ of grease or installation time or buy bolts 1/4 inch shorter to save weight or something idiotic like that.

By: Hunter

Hunter — Thu, 13 Sep 2007 16:39:49 +0000

Yes, the Q400 is the super quiet turbo prop. I’ve flown on Horizon’s and they truly are remarkable.

Interestingly, Bombardier also had problems with the CRJ, although it was the nose gear. The regional for which I used to work had three incidents over 18 months where the nose gear did not drop during the prep for landing. All three landed safely nose to the ground. Two in DFW and one in LAX.

By: CF

CF — Thu, 13 Sep 2007 15:31:03 +0000

Yup, that’s it. I believe that they also make the Q300 shorter body these days, but the Q400 is certainly the most popular. I’ve heard very good things about it, but I’ve never been onboard myself. (I’ve only been on old 100 and 200 models.) I’d like to get on the new Horizon flight from LAX to Sonoma, and if I do I will certainly report back.

By: jason

jason — Thu, 13 Sep 2007 15:03:12 +0000

Isn’t the Q400 the model that has new technology designed to make the cabin quieter, despite being a turboprop?

I’d be curious to get a passenger’s point of view who has taken a ride on one of these.