Bell 412
Joined: Dec 2000
Posts: 675
Likes: 0
From: Desert Rat
Bell 412 main transmission dry run capabilities
I look for an official document outlining the dry run capabilities for main transmissions of Bell 412s. Information is appreciated. Thanks.
Cheers,
Alouette
Cheers,
Alouette
Joined: Sep 2006
Posts: 876
Likes: 0
From: Inside the Industry
You won't find a document as the 412 was certified before dry run was a requirement. The C box would not last long without oil.
I would say loss of MGB oil pressure = land or ditch immediately.
I would say loss of MGB oil pressure = land or ditch immediately.
Joined: Dec 2007
Posts: 253
Likes: 8
From: the land of redemption
Right!
Land/ditch immediately!
Anyways no written document you will find about the 412 MGB run dry capability although my maintenance manager told me once he saw a run dry unofficial bench test in Agusta's plant in mid '80; they cranked up the MGB with the rotor installed at operative RPM for a wile, than untied the drain plug letting go all the oil down wile continuing cranking.
The MGB went off after 50 minutes after all the oil have been spilled away.
Consider it was an hangar testing on a inoperative fuselage without any air cooling and moderate blade pitch, he told me.
No infos about CBOX strength without oil inside it.
Cheers
maeroda
Land/ditch immediately!
Anyways no written document you will find about the 412 MGB run dry capability although my maintenance manager told me once he saw a run dry unofficial bench test in Agusta's plant in mid '80; they cranked up the MGB with the rotor installed at operative RPM for a wile, than untied the drain plug letting go all the oil down wile continuing cranking.
The MGB went off after 50 minutes after all the oil have been spilled away.
Consider it was an hangar testing on a inoperative fuselage without any air cooling and moderate blade pitch, he told me.
No infos about CBOX strength without oil inside it.
Cheers
maeroda
Joined: Dec 2000
Aviation Qualifications: Non-Aircrew
Posts: 724
Likes: 40
From: Arlington, Tx. US
412 Oil Loss
One last year flew 9 minutes to a safe beach landing. Once the failed line was replaced and oil put in the transmission it returned to base for detailed inspection.
So bottom line at least as good as a S-92.
The Sultan
So bottom line at least as good as a S-92.
The Sultan
Joined: Dec 2007
Posts: 253
Likes: 8
From: the land of redemption
Wait....and balance!
Wich type of B412?
AB412 standards & AB412SP's had a different CAT A certification compared to AB412EP's; the first ones had two kinds of T/O profiles (cat A vertical & cat A normal), slightly different from cat A helipad, elevated helipad and runway T/Offs from EP's manuals.
Anyways AB412EP are certified in CAT A, fulfilling JAR/EASA performance class 1,2 (3 of course).
In some cases it is certified in PC2 with exposure time at MTOW higher than standard PC2.
cheers
Wich type of B412?
AB412 standards & AB412SP's had a different CAT A certification compared to AB412EP's; the first ones had two kinds of T/O profiles (cat A vertical & cat A normal), slightly different from cat A helipad, elevated helipad and runway T/Offs from EP's manuals.
Anyways AB412EP are certified in CAT A, fulfilling JAR/EASA performance class 1,2 (3 of course).
In some cases it is certified in PC2 with exposure time at MTOW higher than standard PC2.
cheers
Joined: May 2000
Posts: 297
Likes: 0
From: Phuket
Back in the day (1982) we made our own from index cards and the -10. (think operators manual) but then again we made our own skateboards from old skates nailed to a 2x4 also.....damn I am getting old.
Joined: Nov 2007
Posts: 6
Likes: 0
From: oriental
auto rpm check
hey good eve, anybody here who can educate me regarding the procedures on autorpm check? i am just confused on how to use the two charts, density and pressure altitude, how to use the charts, etc? please help me
Joined: Jan 2006
Posts: 24
Likes: 0
From: Canada
Set 29.92 inches (1013 mb) on the altimeter, climb 2000 ft AGL, adjust airspeed to 65 knots, lower collective to full down, roll throttles to idle stops, maintain aircraft stable at 65 knots with collective full down, note fuel onboard, record outside air temperature, indicated altitude (pressure altitude) and indicated rotor rpm as you pass through 1000 feet above ground - perform a power recovery and return to base.
On the density chart locate recorded outside air temperature then run a vertical line from there up to the pressure altitude recorded at 1000 ft above ground then run a horizontal line left to read the resulting density altitude.
On the autorotation chart locate the density altitude value on the left side of the chart then run a horizontal line right to the weight the helicopter was at the time the auto rotation rotor rpm was recorded, then run a line straight down to find the required autorotation rotor rpm.
On the density chart locate recorded outside air temperature then run a vertical line from there up to the pressure altitude recorded at 1000 ft above ground then run a horizontal line left to read the resulting density altitude.
On the autorotation chart locate the density altitude value on the left side of the chart then run a horizontal line right to the weight the helicopter was at the time the auto rotation rotor rpm was recorded, then run a line straight down to find the required autorotation rotor rpm.
Joined: Nov 2007
Posts: 6
Likes: 0
From: oriental
hello everybody!! anybody here who can teach me on how to properly conduct the auto rpm check of bell 412? I mean step by step on how to perform it using the charts in order to get the target RPM. thanks