All Operators Need To Ground Bombardier Q400s Following 2 Accidents


A second incident has occurred involving the collapse of a right main landing gear shortly after touchdown on a Q400 aircraft operated by SAS. The first incident occurred at Aalborg, Denmark on September 9, 2007. The second incident occurred on September 12, 2007 at Vilnius, Lithuania. There were no reported injuries amongst the crew of four and 48 passengers on board the second aircraft.

As a precautionary measure, Bombardier and Goodrich, the landing gear manufacturer, recommend in an All Operator Message (AOM) that operators of Q400 aircraft having accumulated more than 10,000 landing gear cycles (a cycle is one take-off and landing), be grounded until an inspection of the landing gear is carried out.

Bombardier has delivered more than 160 Q400 aircraft to airlines around the world, of these there are currently about 60 Q400 aircraft with more than 10,000 landing gear cycles.

A Bombardier Air Safety representative has been dispatched to the second incident site to provide assistance to the investigating authorities. Until such time as investigations are concluded by the relevant aviation authorities, Bombardier cannot speculate or comment as to the cause of these incidents.

Source: Bombardier

By Szafiย 
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19 Responses to “All Operators Need To Ground Bombardier Q400s Following 2 Accidents”


  1. 1 balint01 September 14, 2007 at 1:51 pm

    All Nippon Airways said on Thursday it had suspended all flights using 14 Q400 aircraft made by Bombardier after the Canadian government said the craft must be inspected.

    Bombardier asked airlines worldwide on Wednesday to ground 60 of its turboprop planes for inspections after landing gear failures forced two planes to make crash landings in the last couple of days.

    ANA suspended 19 flights on Thursday morning and does not know when it will resume services using Q400s, ANA spokeswoman Keiko Ninomiya said.

    Japan Airlines said it had grounded all 10 of its aircraft of the same model earlier in the day but some are now up and flying after having been inspected. The airline suspended flights using three aircraft on Wednesday.

    Japan has a total of 24 of the aircraft concerned, an official at the Ministry of Land, Infrastructure and Transport said.

    (Reuters)

  2. 2 balint01 September 14, 2007 at 4:44 pm

    Bombardier said a preliminary investigation revealed some corrosion on a part of the landing gear that failed on an SAS Q400 earlier this week. A spokesperson told ATWOnline that the corrosion was evident on the landing gear actuator, which extends and retracts the gear during landing and takeoff.

    “The aircraft touched down on the left main landing gear, followed by the right main landing gear and shortly thereafter the right main landing gear collapsed,” according to a statement from SAS. Prior to landing, a “red light indicated that the right main landing gear was not locked and a go-around was initiated.”

    Transport Canada issued an AD yesterday calling for Q400 operators to conduct visual safety inspections of left and right main landing gear systems and main gear retract actuators that have accumulated 8,000 or more landings or have been in service for more than four years. Bombardier sent two separate air safety teams to investigate the SAS incidents that occurred in Aalborg and Vilnius.

    (ATW Online)

  3. 3 balint01 September 27, 2007 at 4:52 pm

    SAS said on 25SEP2007 that it expects its fleet of 27 Q400s to remain grounded “for at least another week” to allow for required inspections and the replacement of landing gear components.

    Evidence of landing gear corrosion was found on 25 of 27 SAS Q400s when the aircraft were examined following the recent collapse of landing gear on two separate flights (ATWOnline, Sept. 24). SAS said the grounding is costing it SEK10-SEK15 million ($1.5-$2.3 million) daily. It has cancelled hundreds of flights since Sept. 12, when the grounding went into effect.

    (ATW Online)

  4. 4 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) September 29, 2007 at 4:45 pm

    I am a retired flight controls engineer. 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 for 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 in order to confirm my analysis of these failures. Please note that a nose gear incident occurred on a Q400 in Japan on March 13, 2007, and I suspect that it is probable that it contains a similar actuator design as the main landing gear system. Another nose landing gear accident occurred in Munich, Germany on September 21, 2007. 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, some investigators noted the fact that the jam nut backed off and the lockwire was missing. This condition, could eventually cause a disconnection of the rod end, which was also stated by investigators in preliminary reports. This failure may have actually occurred after 10,000 cycles while coupled with severe impact upon landings. This scenario seems very plausible. 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. Early discussions regarding this failure were stated that corrosion in the linkage probably played a major role in the accident. I donโ€™t believe that corrosion played a significant role in these failures. My intention is not to interfere with the official investigation of these accidents, but to offer a feasible scenario to help solve the problem.

  5. 5 szafi September 29, 2007 at 6:09 pm

    Dear Mr Cohen,

    thank you for this very valuable comment. I will make sure Bombardier officials will learn about your opinion and hopefully we will get a response from them, so other readers may be informed about it.

  6. 6 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) September 29, 2007 at 11:30 pm

    Dear szafi,

    If my theory is correct,and Bombardier personnel would like to discuss this problem with me, I will try to help them as much as possible. I will be on vacation next week and will return on October 5th.

  7. 7 szafi September 30, 2007 at 7:26 am

    I hope they will do so. I sent an email to their spokesperson together with the link to this post, so I really hope she will react.
    Enjoy your holiday! I’ve just returned from mine from Croatia and it was perfect ๐Ÿ™‚

  8. 8 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) September 30, 2007 at 5:50 pm

    Dear Szafi,

    I will available on October 5th to discuss this important scenario. I want to congratulate you for realizing the importance of getting to the root of the Q400 accidents. It sounds like you had an exciting vacation in Croatia.

  9. 9 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) September 30, 2007 at 10:00 pm

    Dear Szafi,

    I will be available on October 5th to discuss this important scenario. I want to congratulate you for realizing the importance of getting to the root of the Q400 accidents. It sounds like you had an exciting vacation in Croatia.

  10. 10 szafi October 1, 2007 at 7:24 am

    well, i believe flight safety is always about people’s lives, therefore it is the most important topic about flying. Double checking can never get any more expensive than such an accident. Both philosophycally and literally.

    Croatia is always a fun place to be. ๐Ÿ™‚
    Here is my photo galery about it:
    http://szafi.rulez.org/croatia03/index.htm

  11. 11 balint01 October 1, 2007 at 3:09 pm

    Scandinavian airline SAS said it plans to restart flights using its Dash 8 Q400 planes on 04OCT2007.

    “SAS will deploy the first Q400 aircraft on Thursday, October 4, with the remaining Q400 aircraft returning to operation during the following days,” the company said in a statement.

  12. 12 szafi October 4, 2007 at 1:22 pm

    SAS said it will initiate discussions with Bombardier regarding compensation of approximately SEK500 million ($76.7 million) for the costs and lost income incurred due to the three-week grounding of its Q400s

    See full story here:
    http://www.atwonline.com/news/story.html?storyID=10399

  13. 13 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) October 6, 2007 at 2:31 am

    I hope Bombardier responds to my comments regarding the Q400 landing gear collapses. I have studied the use of locking devices in flight controls and landing gear hydraulic actuator applications for many years, and I will be pleased to offer my expertise in this area. BTW, I reviewed the pictures you took in Croatia and found them very impressive.

  14. 14 szafi October 6, 2007 at 12:29 pm

    Dear Mr Cohen,
    first of all good news: they answered.
    https://airlineworld.wordpress.com/2007/10/03/q400-safety-issues/
    here is a separate article I wrote about this conversation.
    And thanks, yes, Croatia is a very good place for a nice “summer in the autumn” type of holiday. ๐Ÿ™‚
    How was your holiday?

  15. 15 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) October 9, 2007 at 5:11 pm

    Thank you for responding to my comments.
    This is the proper response to my comments at this stage of the investigation. However, I sincerely hope that the relevant agencies take my comments seriously. If the nose gear hardware is different than the main gear, then my comment regarding the use of a locking device may or may not apply. However, it is very possible that the main landing gear actuator may require a locking device to prevent rotation in an environment of severe vibration during the flight regime and high impact loading caused during the landing mode. The use of a jam nut and lockwire without a locking device is not an appropriate device since it relies on friction for the security of the jam nut and tightening of the jam nut with the proper torque. The use of lockwire is not a positive device for preventing rotation of the jam nut, since using human factors in design considerations, the lockwire can be broken or inadvertently omitted. The typical method currently being used in the aircraft industry is the incorporation of a locking device in addition to a jam nut and lockwire. The locking device prevents rotation of the piston. Typical examples of locking devices for male rod end applications are as follows: National Aerospace Standards, NAS513, NAS14227, NAS14198 and NAS1193.

  16. 16 szafi October 10, 2007 at 5:02 pm

    Dear Mr Cohen,

    what do you think? Shall we contact any authority?

  17. 17 Murray Cohen, P.E.(RETIRED, FLIGHT CONTROLS ENGINEER) October 12, 2007 at 4:40 pm

    Dear szafi,

    It is inappropriate to discuss this problem with relevant government agencies at this point in time. They are obligated to do an independent study without interference from outside sources. I am quite confident that they will evaluate this problem carefully and arrive at the correct solution.


  1. 1 Q400 Safety Issues « Airline world Trackback on October 3, 2007 at 9:36 pm
  2. 2 Copenhagen - Another Q400 Accident Again! « Airline world Trackback on October 29, 2007 at 12:52 pm

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