Bell 412
Joined: Jun 2004
Posts: 646
Likes: 18
From: Europe
I just finished my recurrent on the 412 at DFW South location. It's a brand new sim capable of 412EP with EFIS, Fast Fin and 4 axis AP. Extremely detailed visuals and updated flight data. The later was a huge surprise.
The instructor gave us a tail rotor drive shaft failure... Surprise surprise, the 412 is not capable of flight at any speed, Fast fin or not. If you enter an autorotation fast enough your only option is to follow it through the right turn, flaring at about 100-ish ft and of course than the left yaw comes that will turn you about 90º. So the flyaway no longer possible they teach to auto immediately and follow it through the right yaw.
I was on the old 212 sim and slightly newer 412 sim some years ago and I remember you could clearly fly away at a low power setting at vy.
All this has me puzzled; 212/412 fuselage concept - the 212 has spiral dive tendency, too much directional stability, that's why it got the dihedral sail. But now, with new data, we get that something that ought to keep you straight is unable to do just that.
The instructor gave us a tail rotor drive shaft failure... Surprise surprise, the 412 is not capable of flight at any speed, Fast fin or not. If you enter an autorotation fast enough your only option is to follow it through the right turn, flaring at about 100-ish ft and of course than the left yaw comes that will turn you about 90º. So the flyaway no longer possible they teach to auto immediately and follow it through the right yaw.
I was on the old 212 sim and slightly newer 412 sim some years ago and I remember you could clearly fly away at a low power setting at vy.
All this has me puzzled; 212/412 fuselage concept - the 212 has spiral dive tendency, too much directional stability, that's why it got the dihedral sail. But now, with new data, we get that something that ought to keep you straight is unable to do just that.
Joined: Feb 2005
Posts: 23
Likes: 0
From: Canada
"updated flight data" is exactly the reason why you can't fly away in the sim after losing your tail rotor. Many of us had done training in that sim and similar ones where it was possible to fly away. This now appears to have been teaching a response that was incorrect most of the time. Harsh reality since then reinforces that an immediate autorotation is (and was then too) the recommended immediate response. My notes from my last sim session in DFW state enter autorotation, then if altitude permits, check if powered flight is possible. Unfortunately powered flight was always possible in the sim.
News Article | Royal Canadian Air Force | Report | CH146420 Griffon - Epilogue - Flight Safety Investigation Report
News Article | Royal Canadian Air Force | Report | CH146420 Griffon - Epilogue - Flight Safety Investigation Report
Joined: Feb 2009
Posts: 19
Likes: 0
From: Land of the roundabouts.
Engineer ex 412, we were told during training the No 2 would always run hotter then No 1 , if both engines had the same power, due to the position of the thermocouple harness, and the bleed valve positon.also the airflow over the top of the engine cowlings was supposed to cause a difference in itt's. But it doesnt take long for engines to develope different power causing high itt diferences, when I was operating 2 x 412's in the north of Pakistan, Gilgit and Chitral, the gritty landing areas would chew up the engines pretty quick, as for the rotor droop, needs adjusting on the compensator, but the pilot has his beeps anyway. Hope this helps you. 
Joined: Jun 2004
Posts: 646
Likes: 18
From: Europe
I'm familiar with Canadian accident, but they failed to enter autorotation to start with, missing T/R GBX and rotor didn't help the situation either.
The thing that bothers me is why such a severe right yaw in autorotation? If anything, I would expect a left or neutral yaw due to vertical fin.
The thing that bothers me is why such a severe right yaw in autorotation? If anything, I would expect a left or neutral yaw due to vertical fin.
Last edited by Phoinix; 10th December 2015 at 09:37.
Joined: Sep 2005
Posts: 768
Likes: 45
From: Montreal
Fuzzy recall but having one or two AP off was covered in limitations and affected speed, climb and IFR. VFR if you lost one AP you'd turn the second one off so you could keep flying faster than the 212's around you. Normal day.
Joined: Apr 2004
Posts: 134
Likes: 0
From: NO GPS FIX
Joined: Feb 2019
Posts: 3
Likes: 0
From: Iraq
Bell 412 pt6t-3df engines have fluctuate N1, N2, ITT, TRQ AND FULE FLOW at the same time on both engines. Engine #1 another problem during acceleration there is rumble with high ITT and stall . The MM troubleshooting does not mentioned fluctuating problem with both engines simultaneously. I would appreciate if anybody can help .
Last edited by Afshin939; 15th February 2019 at 13:50.
Joined: May 2002
Posts: 2,697
Likes: 71
From: Wanaka, NZ
(If not for the engine with the rumble....) With both engines apparently fluctuating, reduce one throttle and see if fluctuations on the other engine continue. If fluctuations continue, return throttle to full open and repeat process with the other throttle. One engine might have a problem and the other is normal but trying to compensate.
The rumble in ENG #1 needs to be fixed first, sounds like compressor damage or bleed valve issue causing that one.
The rumble in ENG #1 needs to be fixed first, sounds like compressor damage or bleed valve issue causing that one.
Joined: May 2002
Aviation Qualifications: ATP+Mil
Posts: 18,633
Likes: 1,072
From: Downeast
Put the suspect engine in Manual Throttle.....and see if that resolves the Two Engine issue.
Do the same for the other engine and see what happens.
One of them in Normal Governor should show a problem I am thinking.
Do the same for the other engine and see what happens.
One of them in Normal Governor should show a problem I am thinking.
Joined: Mar 2005
Aviation Qualifications: Military
Posts: 6,562
Likes: 952
From: Aus
Had the same sort of problem on a 76A, fluctuating fuel flow, N1, ITT, TQ, as one engine went up, the other went down, as you'd expect. Identified the bad engine by pulling each throttle back in turn out of governing range, having identified the bad left it just out of governing range and things settled down. Brought it home and maintenance unable to fault on a test flight with the CP. Put back on line and thirty minutes or so into the next trip one engine went to zero TQ, I knew from previous flight which was the "bad" engine and having lowered collective to contain the good engine and with hand half way to the throttle the bad engine then went from zero to max TQ in a heart beat. Turned out the drive shaft on the governor flyweights had been binding causing the hand waving of fuel flow, N1, ITT, TQ, and drive shaft ultimately sheared.
Joined: Aug 2012
Posts: 144
Likes: 4
From: Depends on the day!
Bell 412 pt6t-3df engines have fluctuate N1, N2, ITT, TRQ AND FULE FLOW at the same time on both engines. Engine #1 another problem during acceleration there is rumble with high ITT and stall . The MM troubleshooting does not mentioned fluctuating problem with both engines simultaneously. I would appreciate if anybody can help me.
Joined: Oct 2002
Posts: 236
Likes: 4
From: All over the place
From quite a ways back.
https://www.sandiegouniontribune.com...c13-story.html
US agents hold suspected Iran-bound helicopter
December 13th 2009
The Associated Press
Federal agents are investigating whether a helicopter they have held for 14 months at an airport in Texas was earmarked for shipment to Iran.
The agents suspect an Italian company has already shipped two helicopters in contravention of a U.S. trade embargo with Iran, and that the third was also intended for the country. The $8 million aircraft meanwhile sits in a Bell Helicopter hangar at Arlington Municipal Airport, The Dallas Morning News reported in Sunday's edition.
At least one of the aircraft believed shipped to Iran was equipped with night vision and autopilot technology subject to strict U.S. restrictions, the newspaper reported.
A federal seizure of an Iran-bound helicopter is "a unique circumstance" for North Texas agents, said George Richardson, special agent in charge of the U.S. Commerce Department's Bureau of Industry and Security office in Dallas. "This is driven by economics," he told The News.
The Italian company, Tiber Aviation SRL, last year bought three Bell 412 helicopters from Helivan SA of Mexico for about $22 million, the report said. Bell Helicopter says it leased three helicopters to Helivan in Tarrant County but that Helivan was not authorized to sell them.
Tiber asked Swiss-based shipping company Panalpina Inc. to transport the first two helicopters through North Texas to Italy, said Panalpina deputy general counsel Robert Ernest. Panalpina was about to ship the third when a Tiber pilot asked for a quote to ship the aircraft to Iran.
Panalpina refused to ship the aircraft and contacted the U.S. Commerce Department in Dallas, Ernest said.
Tiber has denied intending to ship any of the helicopters to Iran, according to court documents. The ownership of the helicopter is in dispute in a pending lawsuit between Tiber and Textron Financial Corp., a unit of Bell Helicopter Textron, Bell Helicopter's parent company.
The newspaper did not report any comment from Helivan.
The United States has imposed a trade embargo on Iran since 1995, but foreign companies linked to the United States can still use legal loopholes to sell U.S.-made goods legally to nations under U.S. export bans.
"We don't want technology to go to Iran, regardless of whether it will be used militarily or by civilian businesses," said Kenneth Wainstein, former U.S. assistant attorney general for national security.
"We don't want American businesses engaged in trade with a regime whose policies are antithetical to our national interests," he told The News.
---
Information from: The Dallas Morning News, http://www.dallasnews.com
https://www.sandiegouniontribune.com...c13-story.html
US agents hold suspected Iran-bound helicopter
December 13th 2009
The Associated Press
Federal agents are investigating whether a helicopter they have held for 14 months at an airport in Texas was earmarked for shipment to Iran.
The agents suspect an Italian company has already shipped two helicopters in contravention of a U.S. trade embargo with Iran, and that the third was also intended for the country. The $8 million aircraft meanwhile sits in a Bell Helicopter hangar at Arlington Municipal Airport, The Dallas Morning News reported in Sunday's edition.
At least one of the aircraft believed shipped to Iran was equipped with night vision and autopilot technology subject to strict U.S. restrictions, the newspaper reported.
A federal seizure of an Iran-bound helicopter is "a unique circumstance" for North Texas agents, said George Richardson, special agent in charge of the U.S. Commerce Department's Bureau of Industry and Security office in Dallas. "This is driven by economics," he told The News.
The Italian company, Tiber Aviation SRL, last year bought three Bell 412 helicopters from Helivan SA of Mexico for about $22 million, the report said. Bell Helicopter says it leased three helicopters to Helivan in Tarrant County but that Helivan was not authorized to sell them.
Tiber asked Swiss-based shipping company Panalpina Inc. to transport the first two helicopters through North Texas to Italy, said Panalpina deputy general counsel Robert Ernest. Panalpina was about to ship the third when a Tiber pilot asked for a quote to ship the aircraft to Iran.
Panalpina refused to ship the aircraft and contacted the U.S. Commerce Department in Dallas, Ernest said.
Tiber has denied intending to ship any of the helicopters to Iran, according to court documents. The ownership of the helicopter is in dispute in a pending lawsuit between Tiber and Textron Financial Corp., a unit of Bell Helicopter Textron, Bell Helicopter's parent company.
The newspaper did not report any comment from Helivan.
The United States has imposed a trade embargo on Iran since 1995, but foreign companies linked to the United States can still use legal loopholes to sell U.S.-made goods legally to nations under U.S. export bans.
"We don't want technology to go to Iran, regardless of whether it will be used militarily or by civilian businesses," said Kenneth Wainstein, former U.S. assistant attorney general for national security.
"We don't want American businesses engaged in trade with a regime whose policies are antithetical to our national interests," he told The News.
---
Information from: The Dallas Morning News, http://www.dallasnews.com