Click Here for video (Youtube)
Air Moorea Twin Otter crash Aug 2007 45min video . . .
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bizjets101
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Air Moorea Twin Otter crash Aug 2007 45min video . . .
Click Here ASN report On 9 August 2007, Air Moorea Flight 1121, operated on an Air Moorea de Havilland Canada DHC-6 Twin Otter airplane, crashed shortly after taking off from Moorea Airport on Moorea island in French Polynesia; the plane was bound for Tahiti's Faa'a International Airport. According to the official report by Bureau d'Enquêtes et d'Analyses pour la sécurité de l'Aviation Civile, all 20 occupants, 19 passengers and one crew member, died. Two of the passengers were European Union officials.
Click Here for video (Youtube)
Click Here for video (Youtube)
Last edited by bizjets101 on Wed Feb 05, 2014 2:34 am, edited 1 time in total.
Re: Air Moorea Twin Otter crash Aug 2007 45min video . . .
Check your video link...
I guess I should write something here.
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bizjets101
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Re: Air Moorea Twin Otter crash Aug 2007 45min video . . .
Duh!!! Fixed. Click Here.
Re: Air Moorea Twin Otter crash Aug 2007 45min video . . .
That was great, thanks bizjets.
A few take a ways from this:
It is wise to fly reasonably in trim as much as possible, so that in such an event, you have time to trim as required before control is entirely lost, should a cable break. The aircraft has demonstrated the capability to be landed without elevator control during certification, as follows in FAR Part 23.145:
"(e) By using normal flight and power controls, except as otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it must be possible to establish a zero rate of descent at an attitude suitable for a controlled landing without exceeding the operational and structural limitations of the airplane, as follows:
(1) For single-engine and multiengine airplanes, without the use of the primary longitudinal control system."
Bear in mind, that primary flight control cables operate at 10% or so of their breaking strength in most designs. There can be mechanical advantage, which increases cable loads well beyond pilot effort, but not to anywhere near the capacity of the cable, as you begin to get cable stretch at these high loads, which results in sloppy controls. During testing I did in a DA42, I found that the rudder cables normally operate at unusually high loads, though still well below their breaking strength. However, this relatively high normal operating load, and the design of the terminals allowed enough stretch that there were challenges in achieving full rudder deflection to maintain a lower Vmca. But, you can have a lot of cable wear, very easily detected at inspection, before you have an unsafe condition.
The other take a way for me, as I always believed anyway, is that if you need control locks, you need them on the control surface, not the control wheel. Yes, a Twin Otter is awkward to control lock at the controls, but any airplane will be protected from hidden control system damage, if control locks are external. If I had my way with control lock design, cockpit control locks would be prohibited, in favour of external locks - clamp blocks, or a lock like a Caravan rudder.
Good lessons here....
A few take a ways from this:
It is wise to fly reasonably in trim as much as possible, so that in such an event, you have time to trim as required before control is entirely lost, should a cable break. The aircraft has demonstrated the capability to be landed without elevator control during certification, as follows in FAR Part 23.145:
"(e) By using normal flight and power controls, except as otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it must be possible to establish a zero rate of descent at an attitude suitable for a controlled landing without exceeding the operational and structural limitations of the airplane, as follows:
(1) For single-engine and multiengine airplanes, without the use of the primary longitudinal control system."
Bear in mind, that primary flight control cables operate at 10% or so of their breaking strength in most designs. There can be mechanical advantage, which increases cable loads well beyond pilot effort, but not to anywhere near the capacity of the cable, as you begin to get cable stretch at these high loads, which results in sloppy controls. During testing I did in a DA42, I found that the rudder cables normally operate at unusually high loads, though still well below their breaking strength. However, this relatively high normal operating load, and the design of the terminals allowed enough stretch that there were challenges in achieving full rudder deflection to maintain a lower Vmca. But, you can have a lot of cable wear, very easily detected at inspection, before you have an unsafe condition.
The other take a way for me, as I always believed anyway, is that if you need control locks, you need them on the control surface, not the control wheel. Yes, a Twin Otter is awkward to control lock at the controls, but any airplane will be protected from hidden control system damage, if control locks are external. If I had my way with control lock design, cockpit control locks would be prohibited, in favour of external locks - clamp blocks, or a lock like a Caravan rudder.
Good lessons here....
Re: Air Moorea Twin Otter crash Aug 2007 45min video . . .
Gauranteed there would be a lot more crashes because pilots would takeoff without taking out the external locks... The one thing they got right with the metro, is the control locks.
I guess I should write something here.
