ABC
Twenty-eight people died when an Airlines PNG Dash 8 crashed near Madang in October 2011.
Many of those killed were travelling to Madang for a university graduation ceremony.
The Accident Investigation Commission's final report found the pilot damaged the plane's engines on descent by throwing them into reverse after an alarm sounded warning that the plane had reached its maximum speed.
The Commission's CEO David Inau explained the findings to Liam Fox.
Presenter: Liam Fox
Speaker: David Inau, CEO Accident Investigation Commission
INAU: What happened was that on descent, the pilot selected flight idle, so that he can descend at towards Madang. But in this instance, the damper that has auto pilot inputs to control the descent was unserviceable, so the pilot had to manually fly the aircraft from top of descent down to Madang.
Now, in the descent profile, he selected flight idle so that he can get a good rate of descent going, so he can arrive at Madang, but in the process, there was some cloud in the air, so he had to fly around the clouds to get below the cloud as quickly as he can.
The two pilots did not notice the air speed, the air speed had increased, they may have had the nose down too far, the air speed increased to the end approaching the maximum of speed, the warning horn came off. When the warning horn sounded, the pilot in command reach across, selected the power levers and moved them into the beta range. Initially, they were in forward flight, but when he selected reverse flight, the propellers turned into reverse pitch and in the process, damaged the propeller gear box.
FOX: So by trying to slow down, he's accidentally gone into reverse, is that right?
INAU: We cannot ascertain why he selected reverse in flight. He has not revealed anything to us, but when he selected the beta range, which made the propellers go into reverse cycle, that's when the gear box failed.
FOX: And would a pilot normally ever move into beta range while they're in the air?
INAU: There is a strong warning in the flight manual and it's in the report that beta range cannot be used in flight. It's only for ground operations.
FOX: And then once this situation had happened the report says that the crew did not respond to any of the alerts by implementing emergency procedures. Is that correct, and what were those emergency procedures?
INAU: We had the flight data recorder, and the cockpit voice recordings, which indicated to us that there was a total lack of attention to what had happened and the correct procedures to follow after such an event were not followed to try and get the air speed control, the rate of descent control so that they can probably have more time in the air and make sound decisions to landing at a suitable location.
FOX: One of the things that was not done, was extending the landing gear and the use of flaps. What would potentially have happened if those were used?
INAU: Well, with the flaps, extension of the flaps, you may, the speed, the stall speed would have been reduced, so you can fly in at a lower speed and if the landing gear would have been used, it could have assisted in the impact on touching down on the riverbed there.
FOX: So it could potentially have lessened the force of the impact?
INAU: Could have, but we cannot confirm that, but it could have.
FOX: So in laymen's terms, if someone, a member of the public is reading this report or indeed a relative of someone who die, this could be summarised as a crash resulting from pilot error?
INAU: Well, that's what is reported in the papers and the media here in Papua New Guinea at the moment. We have stated the facts in the report. Whatever the readers want to use, and get out of that report, it is their views as well.
FOX: The crash wouldn't have happened if the pilot didn't throw the engines into reverse while near top speed, that's correct though, isn't it?
INAU: Yeah, that is correct.
FOX: The aspect about that emergency procedures weren't followed once the plane got into trouble, what has Airlines PNG done about that particular aspect?
INAU: Ah, Airlines PNG have not indicated publicly to us yet, but one thing that has emanated from all this is that now all, as of today, all Dash 8 aircraft throughout the world are now by law required to have beta lock out system, where selecting the levers past the flight idle gate will not put the props into reverse.
Many of those killed were travelling to Madang for a university graduation ceremony.
The Accident Investigation Commission's final report found the pilot damaged the plane's engines on descent by throwing them into reverse after an alarm sounded warning that the plane had reached its maximum speed.
The Commission's CEO David Inau explained the findings to Liam Fox.
Presenter: Liam Fox
Speaker: David Inau, CEO Accident Investigation Commission
INAU: What happened was that on descent, the pilot selected flight idle, so that he can descend at towards Madang. But in this instance, the damper that has auto pilot inputs to control the descent was unserviceable, so the pilot had to manually fly the aircraft from top of descent down to Madang.
Now, in the descent profile, he selected flight idle so that he can get a good rate of descent going, so he can arrive at Madang, but in the process, there was some cloud in the air, so he had to fly around the clouds to get below the cloud as quickly as he can.
The two pilots did not notice the air speed, the air speed had increased, they may have had the nose down too far, the air speed increased to the end approaching the maximum of speed, the warning horn came off. When the warning horn sounded, the pilot in command reach across, selected the power levers and moved them into the beta range. Initially, they were in forward flight, but when he selected reverse flight, the propellers turned into reverse pitch and in the process, damaged the propeller gear box.
FOX: So by trying to slow down, he's accidentally gone into reverse, is that right?
INAU: We cannot ascertain why he selected reverse in flight. He has not revealed anything to us, but when he selected the beta range, which made the propellers go into reverse cycle, that's when the gear box failed.
FOX: And would a pilot normally ever move into beta range while they're in the air?
INAU: There is a strong warning in the flight manual and it's in the report that beta range cannot be used in flight. It's only for ground operations.
FOX: And then once this situation had happened the report says that the crew did not respond to any of the alerts by implementing emergency procedures. Is that correct, and what were those emergency procedures?
INAU: We had the flight data recorder, and the cockpit voice recordings, which indicated to us that there was a total lack of attention to what had happened and the correct procedures to follow after such an event were not followed to try and get the air speed control, the rate of descent control so that they can probably have more time in the air and make sound decisions to landing at a suitable location.
FOX: One of the things that was not done, was extending the landing gear and the use of flaps. What would potentially have happened if those were used?
INAU: Well, with the flaps, extension of the flaps, you may, the speed, the stall speed would have been reduced, so you can fly in at a lower speed and if the landing gear would have been used, it could have assisted in the impact on touching down on the riverbed there.
FOX: So it could potentially have lessened the force of the impact?
INAU: Could have, but we cannot confirm that, but it could have.
FOX: So in laymen's terms, if someone, a member of the public is reading this report or indeed a relative of someone who die, this could be summarised as a crash resulting from pilot error?
INAU: Well, that's what is reported in the papers and the media here in Papua New Guinea at the moment. We have stated the facts in the report. Whatever the readers want to use, and get out of that report, it is their views as well.
FOX: The crash wouldn't have happened if the pilot didn't throw the engines into reverse while near top speed, that's correct though, isn't it?
INAU: Yeah, that is correct.
FOX: The aspect about that emergency procedures weren't followed once the plane got into trouble, what has Airlines PNG done about that particular aspect?
INAU: Ah, Airlines PNG have not indicated publicly to us yet, but one thing that has emanated from all this is that now all, as of today, all Dash 8 aircraft throughout the world are now by law required to have beta lock out system, where selecting the levers past the flight idle gate will not put the props into reverse.
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