We should not point fingers
Join Date: Oct 2012
Location: Canada
Age: 53
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
Agreed SAS, but some comments from other posters led me to believe that they were not aware how much different it is flying the 61 as opposed to a more modern twin. There is no one number that the Nr is expected to be sitting at on its own.
John: 721 C (-1) or 758 C (-2) are the maximum 2 1/2 minute T5's, so yes, all basically correct except the topping is achieved by limiting Ng. T5 and Q limits must not be exceeded when Ng is topped. During the check 2% Nr droop with the Ng steady at the limit (102.3/103.4) is used.
I disagree a little with the comment:
If the Ng hasn't topped yet (102.3/103.4 Ng), it will still spool up and provide more power, but the engine has been using in excess of t/o (5 min) power since passing 696 C and 100 Ng.
Again, the report won't open for me right now but I recall both Ng's were steady at 102 (102.3...???) as the Nr drooped. No T5 calls were made so we don't know.
John: 721 C (-1) or 758 C (-2) are the maximum 2 1/2 minute T5's, so yes, all basically correct except the topping is achieved by limiting Ng. T5 and Q limits must not be exceeded when Ng is topped. During the check 2% Nr droop with the Ng steady at the limit (102.3/103.4) is used.
I disagree a little with the comment:
He knows that at 721, increasing collective produces no more power, and only results in Nr droop.
Again, the report won't open for me right now but I recall both Ng's were steady at 102 (102.3...???) as the Nr drooped. No T5 calls were made so we don't know.
Topping
P&A,
I was referring to how the maintenance test pilot or the SA production test pilot would check and adjust topping. In temperate/warm conditions, the Ng adjustment was set so that the Ng limiter would result in reaching and not exceeding the limit T5. The engine would then limit at an Ng that would result in the limit T5, which would, in those conditions, be less than the limit Ng number for 2.5 min power.
It had to be extremely cold for that engine to reach the Ng limiter ( i.e., the posted Ng 2.5 minute limit ) prior to reaching the T5 limit.
Some 61's had remote topping adjustments built in, accessible from the cabin ceiling area, but I cannot recall if the commercial models were so equipped. Sure made this task easier.
I was referring to how the maintenance test pilot or the SA production test pilot would check and adjust topping. In temperate/warm conditions, the Ng adjustment was set so that the Ng limiter would result in reaching and not exceeding the limit T5. The engine would then limit at an Ng that would result in the limit T5, which would, in those conditions, be less than the limit Ng number for 2.5 min power.
It had to be extremely cold for that engine to reach the Ng limiter ( i.e., the posted Ng 2.5 minute limit ) prior to reaching the T5 limit.
Some 61's had remote topping adjustments built in, accessible from the cabin ceiling area, but I cannot recall if the commercial models were so equipped. Sure made this task easier.
Last edited by JohnDixson; 9th Feb 2013 at 11:07. Reason: Additional thought
John,
Short version of what you are saying....Topping should be done for the normal conditions the aircraft is going to be operated in....Altitude, OAT?
Meaning to me.....a machine at say Newfoundland working offshore to the rigs from a sea level heliport in the Winter time would have a different setting say as for an aircraft working in the mountains of California in the summer....say 5,000 feet and +25 OAT.
Am I right in what I think you are saying?
Short version of what you are saying....Topping should be done for the normal conditions the aircraft is going to be operated in....Altitude, OAT?
Meaning to me.....a machine at say Newfoundland working offshore to the rigs from a sea level heliport in the Winter time would have a different setting say as for an aircraft working in the mountains of California in the summer....say 5,000 feet and +25 OAT.
Am I right in what I think you are saying?
T-58 Topping
SAS, you are correct.
Remember, the technology utilized in this generation* of GE turboshaft engines is designed so that one is setting up the engine to limit itself to a given T5, by means of setting an adjustment on the mechanical Ng flywheel governor limiter.
This hydro-mechanical control incorporated sensors for both altitude and temperature, and these acted thru levers to adjust fuel flow, but there was a finite range within which an Ng limiter setting would ensure that the resultant Ng value would then result in the T5 limit.
* the USN version of the T-58 which has an analog electrical control superimposed on the hydro- mechanical control ( was called PMS, for Power Management System ), actually controlled engine limiting by measuring and limiting to, rated T5. I forget the dash number of this T-58, but I certainly recall that the reliability of this, GE's first shot at electronic engine control, was such that the USN insisted on installing a PMS OFF switch on the cyclic. Can't blame the USN aviators: 50% of their flying was at night, max altitude 150 ft, multiple approaches to sonar dip points, time spent in an IFR hover etc etc., an environment wherein any uncommanded shenanigans by the engines is really unneeded.
Remember, the technology utilized in this generation* of GE turboshaft engines is designed so that one is setting up the engine to limit itself to a given T5, by means of setting an adjustment on the mechanical Ng flywheel governor limiter.
This hydro-mechanical control incorporated sensors for both altitude and temperature, and these acted thru levers to adjust fuel flow, but there was a finite range within which an Ng limiter setting would ensure that the resultant Ng value would then result in the T5 limit.
* the USN version of the T-58 which has an analog electrical control superimposed on the hydro- mechanical control ( was called PMS, for Power Management System ), actually controlled engine limiting by measuring and limiting to, rated T5. I forget the dash number of this T-58, but I certainly recall that the reliability of this, GE's first shot at electronic engine control, was such that the USN insisted on installing a PMS OFF switch on the cyclic. Can't blame the USN aviators: 50% of their flying was at night, max altitude 150 ft, multiple approaches to sonar dip points, time spent in an IFR hover etc etc., an environment wherein any uncommanded shenanigans by the engines is really unneeded.
Night IMC Hovering over the Sea....now that would be great fun....riding the SONAR Hobby Horse!
I don’t know if this applies to the T-58 but the GE-T-64 had a similar remote topping adjustment. For the reasons discussed in this thread NAVAIRSYSCOM and Sikorsky decided to eliminate the requirement for remote topping adjustments on the T-64 sometime in the late 1970s or early 1980s. The adjustment knob on the fuel control was rotated to its maximum adjustment position thus requiring the pilots to closely monitor the limitations when operating at maximum power. In, the fuel control incorporated a mechanical flywheel type governor that limited the maximum Ng to 102.5%. This flywheel governor was removed on the latest 419 series of engine allowing the engine to achieve maximum absolute power (5000 ESHP) during OEI situations. Ngs greater than 102.5 were considered a one time event thus requiring engine removal once these extreme power levels were utilized.
Join Date: Oct 2012
Location: Canada
Age: 53
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
John:
Yes they are equipped. I was doing this as recently as this past summer and referred back to the company SOP we were using (140-2).
Even in extremely hot environments we would achieve topping with T5 margins (choosing an appropriate test flt altitude).
I believe from your notes above that your experience is on the Sea King. I am unsure which engine variant you are talking about, as it may explain our different experiences.
Some 61's had remote topping adjustments built in, accessible from the cabin ceiling area, but I cannot recall if the commercial models were so equipped. Sure made this task easier.
Even in extremely hot environments we would achieve topping with T5 margins (choosing an appropriate test flt altitude).
I believe from your notes above that your experience is on the Sea King. I am unsure which engine variant you are talking about, as it may explain our different experiences.
Last edited by pilot and apprentice; 9th Feb 2013 at 21:13.
P and A.....what is your take on the NTSB Report re Engine Topping procedures being used by the Operator for Iron 44's operations (considering Altitude/OAT)?
Which parameter would the Crew have used to limit power that day...T5, Ng, Q? Which limit would they have hit first?
Which parameter would the Crew have used to limit power that day...T5, Ng, Q? Which limit would they have hit first?
Topping
P and A,
I think the 140-2 was the last iteration of commercial T-58's that we saw. And your note does bring to mind that there was some difference in setting up topping on those engines, which in all honesty I can't recall, thus I am sure you are correct. During my time at SA, I had a chance to fly the SH-3A,D,G,H. CH/HH-3C,E. S-61L,N. S-61R, S-67. RH-3A ( minesweeper ). VH-3A,D. HH-3F ( USCG ).
The report didn't say which version were installed in the accident machine, and I am guessing that you are saying they had 140-2's?
I think the 140-2 was the last iteration of commercial T-58's that we saw. And your note does bring to mind that there was some difference in setting up topping on those engines, which in all honesty I can't recall, thus I am sure you are correct. During my time at SA, I had a chance to fly the SH-3A,D,G,H. CH/HH-3C,E. S-61L,N. S-61R, S-67. RH-3A ( minesweeper ). VH-3A,D. HH-3F ( USCG ).
The report didn't say which version were installed in the accident machine, and I am guessing that you are saying they had 140-2's?
Join Date: Oct 2012
Location: Canada
Age: 53
Posts: 215
Likes: 0
Received 0 Likes
on
0 Posts
John,
I have had trouble getting into the report to verify but I recall the Ng's were reported as topped at 102%. 102.3% Ng is the target for topping the 140-1. I am sure it would be in there.
I have been explaining the 61 in general as much as talking about this incident. I am envious of your experience! Learning the in's and out's of a new type is one of the few things I really enjoy about this business.
SAS,
I would expect that the Ng and T5 would be reached at close to the same time for -2, unsure right now what they were using.
I have had trouble getting into the report to verify but I recall the Ng's were reported as topped at 102%. 102.3% Ng is the target for topping the 140-1. I am sure it would be in there.
I have been explaining the 61 in general as much as talking about this incident. I am envious of your experience! Learning the in's and out's of a new type is one of the few things I really enjoy about this business.
SAS,
I would expect that the Ng and T5 would be reached at close to the same time for -2, unsure right now what they were using.
Join Date: Jul 2007
Location: Canada
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
140-1 and 140-2 are the same engine and fuel control, just set to higher Ng limits.
To set Ng topping we simply climbed (standard lapse rate with spec engine would put you at ~ 8000) until we could get Ng topping (2% droop) without exceeding (696) T5 limits.
Also, normal T/O power doesn't change bewteen -1 and -2 limits, you just have more power available OEI.
Whether you to will hit the Ng or T5 limit first would depend on how the engine was built. You can "trade" Ng for T5 on overhaul. In this case, it is likely he hit T5 first.
To set Ng topping we simply climbed (standard lapse rate with spec engine would put you at ~ 8000) until we could get Ng topping (2% droop) without exceeding (696) T5 limits.
Also, normal T/O power doesn't change bewteen -1 and -2 limits, you just have more power available OEI.
Whether you to will hit the Ng or T5 limit first would depend on how the engine was built. You can "trade" Ng for T5 on overhaul. In this case, it is likely he hit T5 first.
Last edited by oleary; 10th Feb 2013 at 03:00.
Join Date: Jul 2007
Location: Canada
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
Yeah, there has been confusion about this for a long time.
A chap who went on to become one of Okie's C/P's and I had an uhmmm, ... strong debate about it.
He insisted we could use 721 and 102.3 for T/O with both engines operating. My take from the GE manual was 696 and 100.
Where -2 really helped us was if we lost a donk.
And loggers? Well, they are .... loggers - after all
A chap who went on to become one of Okie's C/P's and I had an uhmmm, ... strong debate about it.
He insisted we could use 721 and 102.3 for T/O with both engines operating. My take from the GE manual was 696 and 100.Where -2 really helped us was if we lost a donk.
And loggers? Well, they are .... loggers - after all
Last edited by oleary; 10th Feb 2013 at 03:01.
Join Date: Jul 2007
Location: Canada
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
I agree.
I have always taken the position that the customer was paying for one of 4 limits: 696 T5/100 Ng/103Q or max weight (20,500 internal and 22,000 external) But sometimes when night (IFR?
) slinging in the Arctic keeping to 22K lbs was a bit of a battle 
And I tried to apply the same conceptual limits to all the other rockets I flew, as well.
I have always taken the position that the customer was paying for one of 4 limits: 696 T5/100 Ng/103Q or max weight (20,500 internal and 22,000 external) But sometimes when night (IFR?
) slinging in the Arctic keeping to 22K lbs was a bit of a battle And I tried to apply the same conceptual limits to all the other rockets I flew, as well.
Last edited by oleary; 9th Feb 2013 at 22:58.
The CVR recordings seem to indicate that is the profile used....that being a Take off from the Ground with no Hover Power Check done beyond considering weight and balance data, OAT, and recollection of the previous two takeoffs from the first two sorties from that site.
If that is the case...no actual hovering of the aircraft to confirm what power the aircraft was demanding and what reserve was available...then in my view the Crew made a fatal mistake that day.
Add in the crew being unaware of the bogus Weight data provided by the company and compounded by the false performance data as well. I see them falling into a trap.
They should have been doing a Hover Power check for each takeoff as a good safety habit.
Join Date: Aug 2003
Location: Sale, Australia
Age: 80
Posts: 3,833
Likes: 0
Received 0 Likes
on
0 Posts
http://www.ainalerts.com/AINsafety/021813.html
Jury Indicts Two in Helicopter Accident
Two former Carson Helicopter Services executives, Steven Metheny and Levi Phillips, were indicted by a federal grand jury February 1 for “endangering the safety of flight” by falsifying aircraft documents, including weight-and-balance and performance charts on a Sikorsky S-61N helicopter owned and operated by the company. The helicopter crashed in December 2008 while performing firefighting duties for the U.S. Forest Service (USFS). Nine of 13 people aboard were killed in the crash, while four others received serious injuries. Metheny was a former vice president of Carson, and Phillips was the former director of maintenance and reported directly to Metheny. Both were charged with conspiracy to defraud the USFS involving contracts awarded to Carson in 2008. Metheny was also charged with mail and wire fraud, making false statements to the USFS, endangering the safety of aircraft in flight and theft from an interstate shipment.
Jury Indicts Two in Helicopter Accident
Two former Carson Helicopter Services executives, Steven Metheny and Levi Phillips, were indicted by a federal grand jury February 1 for “endangering the safety of flight” by falsifying aircraft documents, including weight-and-balance and performance charts on a Sikorsky S-61N helicopter owned and operated by the company. The helicopter crashed in December 2008 while performing firefighting duties for the U.S. Forest Service (USFS). Nine of 13 people aboard were killed in the crash, while four others received serious injuries. Metheny was a former vice president of Carson, and Phillips was the former director of maintenance and reported directly to Metheny. Both were charged with conspiracy to defraud the USFS involving contracts awarded to Carson in 2008. Metheny was also charged with mail and wire fraud, making false statements to the USFS, endangering the safety of aircraft in flight and theft from an interstate shipment.
Accountability. This may be quick, a plea deal, or long and drawn out.
For John D, and the variations on the T-58's in use by the USN.
I seem to recall that the SH-3's were powered by the T-58 Dash 10 engines (-10), while the H-2's I flew were powered by the Dash 8 (-8) and the CH-46 by the Dash 16. (-16) ... but my memory may be screwing this up.
For John D, and the variations on the T-58's in use by the USN.
I seem to recall that the SH-3's were powered by the T-58 Dash 10 engines (-10), while the H-2's I flew were powered by the Dash 8 (-8) and the CH-46 by the Dash 16. (-16) ... but my memory may be screwing this up.