Archive for October 3rd, 2007

Q400 Safety Issues

As AirlineWorld reported earlier, all Bombardier Q400s were advised to be grounded for a security check following the accident of Scandinavian Airline’s flight to Aalborg on September 9, 2007.

Following the article, we received a comment from Mr Murray Cohen:

“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 don’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.”

I wrote a letter to Bombardier and I was given the following answer:

“Investigations into the Q400 right main landing gear incidents in Denmark
and Lithuania are
still continuing, as are the investigations into the nose landing gear
incidents in Japan and Munich.

We cannot comment or speculate on the root causes of these incidents until
such time as
the authorities have concluded their investigations and issued  their final
reports. We can however advise
that on the basis of published preliminary reports and comments by the
authorities as to the focus of their
investigations,  there is no relationship between the two nose landing gear
incidents and no relationship
between those and the Danish and Lithuanian incidents.

We suggest you contact the relevant aviation authorities for more
information.”

I think it is a correct answer and naturally we will carry on and contact the relevant authorities. In the meantime Mr Murray has left for holiday, but we are waiting for his comment.

If you are interested in the follow-up of this conversation, please make sure to add our blog’s RSS to your RSS reader!

By Szafi 
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Music and Flying II – U2 or U-2?

Some days ago we started a block about music and flying. The first article was about Rammstein. This is the second article of the series.

The Irish rock Band U2 is known probably to most people on this planet. However it is not necessarily known that a military plane manufactured by Lockheed had the same name. It is not official that the band was named after the plane, but taking the fact their biggest idol was Led Zeppelin which also refers to flying, it might have a relationship with it.

So what is U-2?

Lockheed U-2 is also named Dragon Lady. It is a surveillance plane used by the US Air Force. It was developed in the early 1950s, when the cold war made it necessary to know more about each other’s technologies. U-2’s cruising hight is 70 000 feet (jets fly at around 35 000 feet), so it is not vulnerable by missiles and besides that is is outside the reach of radar detection. The plane was designed by Clarence “Kelly” Johnson, who was well known at that time in the US army as he designed more aircrafts active at that time. First it was rejected by the army, but later CIA’s attention was drawn to it and following a personal meeting with president Eisenhower, the US ordered the first 20 aircrafts from Lockheed. The Dragon Lady has large wingspan, which makes it easier to fly high, but it makes the aircraft sensitive for crosswind, so landing is not easy with it.

U-2U-2 cockpitU-2 landing

There is a lot to learn about this very special aircraft, so I collected some links for those interested in it:

Wikipedia’s article about the U-2

About U-2 on the website of Federation of American Scientists

James Huggins’ site – his brother was a U-2 pilot

And what is U2?

Well, there is not too much to tell about the relationship between the band itself and aviation. So if you would like to learn more about the band, the best source is Wikipedia. 🙂

By Szafi

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