Preliminary report issued on Maldives DHC-6 training flight accident

October 16, 2011

The Maldives Accident Investigation Coordinating Committe published a preliminary investigation report regarding the July 11, 2011 accident involving a DHC-6 Twin Otter.

The float-equipped de Havilland Canada DHC-6 Twin Otter sustained substantial damage in a heavy landing in Biyaadhoo Training Lagoon, Maldives. The two pilots on board were not injured. The airplane was used for an annual re-current training flight. Departure time at Malé (MLE) was 08:20 and the flight had to be back before 09:30 because both crew members were scheduled to do a commercial flight at that time.
During the training five landings and take-offs were made simulating different conditions of flight. All these landings and take-offs were made inside the lagoon except the last landing where the crew decided to land on open water outside the lagoon. The crew were simulating a tail wind/single engine landing.
As per the crew, the aircraft initial touch down was smooth. However, they stroke a wave which made the aircraft bounce foe about 20 feet. With the low power aircraft hit the water again with great impact, resulting multiple float attachments to break. Both front and main spreader bars broke and floats rose up, twisted and hitting the bottom engine cowlings. Propeller cuts were found on front of both floats. Also, the flaps as well as the flap selectors were found on the zero position.

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FAA proposes $269,000 civil penalty against The Parachute Center

August 29, 2011

The U.S. Federal Aviation Administration (FAA) is proposing a $269,000 civil penalty against The Parachute Center, of Acampo, Calif., for allegedly operating a de Havilland Canada DHC-6 Twin Otter on 41 flights when it was not in compliance with federal aviation regulations.

The FAA alleges that The Parachute Center failed to comply with a 2009 Airworthiness Directive requiring repetitive inspections of the left and right front spar adapter assemblies to identify cracks that might threaten the structural integrity of the airplane. According to the FAA, the company operated the aircraft between November 2 and November 15, 2009, when it was out of compliance with the airworthiness directive.

The Parachute Center has 30 days from the receipt of the FAA’s enforcement letter to respond to the Agency.

The operator had also been involved in a proposed fine of $664,000 in October 2010.

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FAA proposes $664,000 civil penalty against Parachute Center

October 13, 2010

The U.S. Federal Aviation Administration (FAA) is proposing a $664,000 civil penalty against William C. Dause, doing business as The Parachute Center of Acampo, Calif., for allegedly failing to perform required aircraft parts replacements and failing to comply with safety directives.

The FAA alleges that The Parachute Center operated a de Havilland DHC-6 Twin Otter when critical parts were well past their life limits and without inspecting portions of the wings for corrosion.

In all, the FAA alleges that The Parachute Center operated the aircraft on approximately 2,121 flights between March 21, 2008 and Nov. 4, 2009 with elevator control cables that were overdue for replacement and when the plane was not in compliance with Airworthiness Directives requiring visual inspections of the wing main spar, lower spar cap extensions and wing support strut for possible corrosion.

The FAA also alleges that the company operated the aircraft on at least 500 flights between April 16, 2009 and Nov. 4, 2009 with aileron control cables that were overdue for replacement.

The Parachute Center has 30 days from receipt of the FAA’s enforcement letter to respond to the agency.


Report: fatigue cracking caused gear failure of Swedish DHC-6 Twin Otter

June 21, 2010

A de Havilland Canada DHC-6 Twin Otter sustained substantial damage in a landing gear failure in Sweden in June 2009. The Swedish accident investigators concluded that the gear fractured as the result of a fatigue crack.

The pilot intended to take off with 21 parachutists on board the aircraft. He did not notice anything abnormal, neither during the preparations for take-off nor during the initial taxiing.
After taxiing for a few minutes at low speed, suddenly the right main landing gear broke, whereupon the aircraft tipped over to the right and the right wing struck the ground. The aircraft then slowed down, turned somewhat to the right, and stopped. No person onboard was injured.
The technical examination of the aircraft has shown that the right main landing gear fractured as the result of a fatigue crack. The crack consisted of several smaller fatigue cracks that had grown and joined. The cracks had initiated in an external welded joint and developed over an extended period of time without being detected.
The aircraft type has been exposed to landing gear fracture before as the result of fatigue cracks in the actual area. Current maintenance system prescribes NDT inspection of the landing gear within intervals of 12,000 flying hours or five years, whichever comes first.

The Swedish Accident Investigation Board recommends that EASA and the Swedish Transport Agency, in conjunction with the manufacturer, consider the need for supplementing the present maintenance system in respect of crack formation in the landing gear.


VFR flight into cloud caused Indonesian DHC-6 Twin Otter CFIT accident

April 22, 2010

Indonesian accident investigators of the National Transportation Safety Committee (NTSC) have concluded that a fatal accident involving a DHC-6 Twin Otter in August 2009 has been caused by VFR flight into cloud. The airplane flew into the side of a mountain, killing all 15 on board.

Wreckage of Twin Otter PK-NVC on the mountainside

The Merpati Nusantara Airlines DHC-6 Twin Otter passenger plane flew into the side of a mountain during a domestic flight from Jayapura (DJJ) to Oksibil Airport (OKL). Merpati Flight MZ9760D took off at 10:15 with an estimated time of arrival at Oksibil of 11:05. The pilots were operating under visual flight rules (VFR) procedures. This required them to remain clear of cloud. Ten minutes before impact the pilot in command mentioned climbing to 10,000 feet, and stated “if we cannot go visual I will turn left”. The cockpit conversations did not exhibit any signs of stress or concern until two minutes before the impact, when the copilot mentioned haze and asked the captain if he could see. Fifty seconds before impact, the copilot expressed further concern and asked about the captain’s intentions, and the captain said “climb, to the left”. Forty-two seconds before impact the copilot asked if it was safe on the left.
The copilot became increasingly uncertain about the safety of the flight, specifically mentioning visibility and speed. From the recorded sounds, it is apparent that 13 seconds before impact, engine power was increased symmetrically to a high power setting. The Twin Otter struck the side of a mountain at an elevation of 9300 feet.
The wreckage was located August 4 with some difficulty because the ELT was unserviceable.

As a result of this investigation, the National Transportation Safety Committee
issued recommendations to address safety issues, specifically with respect to: maintenance procedures and maintenance inspection programs, to ensure that Emergency Locator Transmitters are serviceable; and the provision of weather information services for all civilian aircraft operations throughout Papua.


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