USN MH-60S Down San Diego

[Protolanguage]

San Diego Tribune is reporting a Seahawk crashed on the flight deck of the carrier Abraham Lincoln off San Diego ,Wednesday ,5 missing 1 rescued from the ocean .Search continues .Thoughts and prayers are with all concerned .

[Lonewolf_50]

Thanks, my initial post seems to have drifted down a bit. I deleted it, as yours has a better title. :)
The Navy reported that an MH-60S Knighthawk operating from the Abraham Lincoln (CV-72) went into the ocean about 60 miles off shore. Six souls on board, one recovered so far. Early report from a local newspaper here (https://www.sandiegouniontribune.com/news/military/story/2021-08-31/navy-helicopter-crash).
Some follow up information (https://abc30.com/navy-sailors-killed-san-diego-helicopter-crash-uss-abraham-lincoln-coast/11008237/) that doesn't really answer many questions (Navy has confirmed that the other 5 personnel on board have lost their lives :().
I have gone through the Naval Safety Center web page and can't find the summary the news sources are referring to.
The helicopter reportedly touched down on the flight deck and "experienced side-to-side vibrations." It caused the main rotor to strike the deck and fall over the side of the aircraft carrier. Another source (https://www.villagenews.com/story/2021/09/02/news/navy-releases-details-on-deadly-crash-of-helicopter-into-ocean/67540.html) described it a little differently
The MH-60S Knighthawk began undergoing ``side-to-side vibrations'' while landing on the aircraft carrier USS Abraham Lincoln during a routine flight operations roughly 60 nautical miles from shore about 4:30 p.m. last Tuesday, according to a brief preliminary accident summary released by the Naval Safety Center. As the aircraft lurched back and forth, its main rotor struck the deck of the ship, and the impact caused the helicopter to tumble into the sea, the agency reported.
My estimate is something like dynamic rollover (presuming a heading roughly in the direction ship was heading near spot 3 or 4 on the port side of the flight deck, which is where helicopters usually arrive and depart on a CVN)
but
since I have no idea what "experienced side to side vibrations" refers to it's not a very well informed estimate.
Note: I flew and instructed in Seahawks but it's been a while. Based on the information available, which is sparse, that's all I can come up with for why (a) the main rotor blades struck the deck and (b) it then went over the side.
There may be another explanation, though, which may render this estimate moot as more information becomes available.
The "lurched side to side" observation may point toward a hydraulic, or flight control, system anomaly of some kind.
FWIW, an old version of the NATOPS manual for the CH-60S identifies 15 degrees as a critical angle (regarding sloped landings/takeoffs) but points out that there's a lot more to it than that ...
Dynamic rollover is a condition that can occur during takeoff or landing with one wheel on the ground. It is not definable by a single number, nor is it simply a function of slope angle or lateral control authority. These factors will aggravate it, but the main contributor to dynamic rollover is a buildup of angular velocity at the helicopter’s center of gravity about the wheel touching the ground. When the resulting angular momentum of the helicopter about that wheel is greater than can be countered with full opposite lateral cyclic, the helicopter will roll over. (Chapter 11, CH-60S NATOPS from over a decade ago)





Since the helicopter went over the side, which I'll assume is the port side, my suspicion is that it had an amount of left drift, a mainmount contacted the flight deck, and there was sufficient inertia that the dynamic rollover critical angle was reached or exceeded.

[[email protected]]

I would suggest the 'side to side' vibration was ground resonance rather than dynamic rollover.

I had this very badly in a Wessex many years ago on rotor start due to unequal tyre pressures (servicing error) and by the time I retarded the speed select lever and applied the rotor brake each wheel was alternately lifting over a foot off the ground and the ground crew were heading in the opposite direction very quickly.

Fortunately we didn't rollover but it was a scary moment.

It can be a function of tyre pressures, oleo pressures or a MR imbalance aggravating the natural frequency of the undercarriage.

The sequence of events described in the reports matches exactly an uncorrected ground resonance situation - eventually the rapidly increasing magnitude of the 'padding' would cause a rotor strike.

The solution is to lift to the hover if you have flying Nr.

[Lonewolf_50]

I would suggest the 'side to side' vibration was ground resonance rather than dynamic rollover. The report did not indicate that the aircraft was chained / chocked to the deck, which is why I didn't think of that as an issue. But I suppose that there are a variety of ways to enter ground resonance.
Beyond that I won't go - if they landed, got into ground resonance, and didn't lift back off right away I can see the point you are making.

But I am guessing again here.

I don't remember how badly the lateral vibes get when the main rotor dampers leak all of their fluid out, but I do not recall that particular mechanical failure being taught to us as so severe that it makes the aircraft unflyable. Perhaps John Dixson may be able to shed some light on that if he drops by).

There's another possible scenario that occurred to me during lunch.

A few hears ago a UH-60L (from which the CH-60S => MH-60S is directly descended) had a considerable length the skin (aft of the spar) on a main rotor blade come off in flight. The aircraft got a heavy vibration, the crew did an autorotation, and they reported very heavy vibes at the bottom when they cushioned the landing at the end. (All walked away).
That offers me another possible scenario as I think through that very sparse report: what got that observed lateral behavior started?
If, as they approached the ship, a similar blade skin dis-bond happened, severe vibes would show up since they still had power on. Again, the lack of detail leaves this as "a guess" ... I suspect that it will be a while before more is known as the investigation has begun in earnest.

Thanks for sharing your thoughts, crab.

[[email protected]]

Lonewolf - yes I think a blade delamination or a faulty drag damper could easily cause the resonance - we had a situation in NI many years ago where a blade drag damper lock was left in and the aircraft started up. It was stable enough until flying Nr was reached and then it went pear-shaped very quickly - ISTR the crew got it airborne and then carried out a prompt running landing, shutting down the rotors as soon as the wheels touched the ground. Wessex pilots were very au fait with ground resonance issues.

I can imagine a crew, unfamiliar with the rapid onset of ground resonance, wanting to keep it on the deck as you don't know if it will get worse in the air - good idea but shut down the rotors immediately.

We used to demonstrate a damper check as part of the airtest qualification on the Sea King - you sat in the hover and circled the cyclic once or twice (fairly small circles but quickly) and then stopped to see how long it took for any oscillations to stop - a faulty drag damper was evidenced by a slow to reduce 1R.

It was possible to set up a sympathetic oscillation in the rotor which persisted as a 5R for a few seconds and was very unpleasant - a pilot who was trying to fault diagnose a damper issue managed exactly this and though he had lost control, dumped the lever and trashed a perfectly serviceable aircraft.

[JohnDixson]

Crab and Lonewolf:

The ground resonance testing ( mechanical stability is the term used in the Engr Dept ) involves depleting the MR damper fluid, the tire pressure and the landing gear strut servicing. The Naval aircraft main gear ( Seahawk ) are quite different than the Army S-70 gear BTW*. In any case neither was conducive to the rapid entry into ground resonance experienced on the S-58.
*The Army gear design was greatly influenced by their very severe crash-worthy requirements, while the USN gear was very influenced by the frigate landing requirements. Those who have been to PXT can still see the 50 x 50 ft pad they built on a 9 degree slope. Landing at 12 ft/sec was “ interesting “. Actually we had asked for a larger pad, but the USN gave us 50. Trouble was that getting the vertical speed under control within 1 ft/sec isn’t easy and we were starting well above 100 ft and I couldn’t see the pad, even after taking the door off. Solution was that Seahwak Test Director CDR Jack Costello put on a flight suit, acquired a prtable UHF radio, stood on that slope and gave us a GCS for the first part of the descent. He was, as you can imagine, pretty close to the ship when we hit the ground.
Jack Costello, in a previous career, had flown Seals into North Vietnam in a UH-2.

[Lonewolf_50]

Crab and Lonewolf:

The ground resonance testing ( mechanical stability is the term used in the Engr Dept ) involves depleting the MR damper fluid, the tire pressure and the landing gear strut servicing. The Naval aircraft main gear ( Seahawk ) are quite different than the Army S-70 gear BTW*. In any case neither was conducive to the rapid entry into ground resonance experienced on the S-58.
*The Army gear design was greatly influenced by their very severe crash-worthy requirements, while the USN gear was very influenced by the frigate landing requirements. Those who have been to PXT can still see the 50 x 50 ft pad they built on a 9 degree slope. Landing at 12 ft/sec was “ interesting “. Actually we had asked for a larger pad, but the USN gave us 50. Trouble was that getting the vertical speed under control within 1 ft/sec isn’t easy and we were starting well above 100 ft and I couldn’t see the pad, even after taking the door off. Solution was that Seahwak Test Director CDR Jack Costello put on a flight suit, acquired a prtable UHF radio, stood on that slope and gave us a GCS for the first part of the descent. He was, as you can imagine, pretty close to the ship when we hit the ground.
Jack Costello, in a previous career, had flown Seals into North Vietnam in a UH-2. Wow, that's a blast from the past. Jack Costello. Had not heard his name in some years (I remember first meeting him when I was a JO flying SH-2F's).

[JohnDixson]

Jack also saved a member of the Sikorsky Engr crew. This person was in a saloon in the PXT area ( an SA crew was crewing/assisting the USN during some follow-up testing ) and got into a " loud discussion " with the guy next to him in the bar. It progressed and they went outside to settle the matter......except this guy's two pals also went outside, so our guy wound up getting beat up by three. Jack went outside to see how things were going, saw what was happening and ( oh, I forgot to mention that Jack boxed in college and had been a bouncer to earn some spending $ ) decked the three fellows. Should have put Jack in for a Winged S Award*
*get one of these if you rescue someone while flying a Sikorsky helicopter.....well...this was sorta in line with the basic idea..

[megan]

rapid entry into ground resonance experienced on the S-58We had a H-34 at Ellyson that fell on its side during a mag check - at least that's what we were told was the cause.

[chopper2004]

The first real world mission for the Flying Leathernecks new King Stallion involved the recovery of said MH-60S. Pair of VMX-1 King STallions were undergoing OT & E at 29 Palms nearby so they got the call from the Navy Safety Center to assist with the lift.

https://www.navair.navy.mil/news/CH-53K-King-Stallion-logs-first-successful-fleet-mission/Wed-09082021-2033

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/210905_m_ee465_1208_b608f9494b55eff219e29bcf6407ee9845705c68 .jpg
cheers

[SplineDrive]

The first real world mission for the Flying Leathernecks new King Stallion involved the recovery of said MH-60S. Pair of VMX-1 King STallions were undergoing OT & E at 29 Palms nearby so they got the call from the Navy Safety Center to assist with the lift.

https://www.navair.navy.mil/news/CH-53K-King-Stallion-logs-first-successful-fleet-mission/Wed-09082021-2033

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1333/210905_m_ee465_1208_b608f9494b55eff219e29bcf6407ee9845705c68 .jpg
cheers

https://www.thedrive.com/the-war-zone/42329/marines-ch-53k-king-stallion-lifts-stricken-mh-60-seahawk-in-its-first-real-world-mission

Here's a good article covering the lift.

[The Sultan]

Report:

https://www.cpf.navy.mil/Portals/52/Downloads/FOIA-Reading-Room/2022/hsc-8-04-command-investigation.pdf?ver=d8ViUIiIQmI0d85ijQ384A%3d%3d

From the report:

The mishap was caused by the failure of the yellow damper hose on LT 616 in-flight, resulting in total loss of main rotor system damping and the immediate onset of severe vibrations upon touchdown.

So the accident was caused by ground resonance resulting from rotor head line failure. If the report is taken literally a single fluid hose to a single damper failed resulting in the loss of damping in all four blade dampers!! How can this be true? Can someone familiar with the design verify that this is not the case? If true how could such a design be approved?

Assuming that the report’s wording was poorly chosen and should have been “loss of damping to the single blade”, this raises the further question on why loosing a single blade’s damper would be catastrophic? Note: Commercial certification requires demonstrating safe operation with a single damper failed.

[Lonewolf_50]

If true how could such a design be approved? If you look at the millions of flight hours that the S-70 has flown since introduction, because it works. (Seahawk and Blackhawk share that common lineage).
For What It's Worth: not surprised that the lateral disturbance seems to have been related to dampers. In my experience, main rotor dampers were a source of never ending attention, and frustration, when I was in the Fleet around 30 years ago. I would need to dig into the NAVSAFCEN's data base on mishaps to dig out such ones as had dampers as a contributing factor, but it's been a long time since I was in a job that allowed me access to that.
I suspect that there is a little more to be learned on this. I'd love to see if any changes to the NATOPS were made for the CH-60S as a result (in terms of 'if you run into this, do that') instructions.
No further speculation will be made by me.
PS: thanks for the link, :ok: the JAGMAN report will get a more thorough read from me later on.

[[email protected]]

You have two options when you encounter ground resonance like that - either get airborne again or shut down really quickly, it would seem the pilot did neither.

[JimEli]

automatic blade folding

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1200x798/sh60_917392ed6b1b02aeaaf94890ff79e9bb70263efa.jpg

[212man]

You have two options when you encounter ground resonance like that - either get airborne again or shut down really quickly, it would seem the pilot did neither.
The surviving crewman states on Page 20 that he saw the pilots attempting to secure the PCLs. I guess the vibrations prevented them doing so in time.

[[email protected]]

The surviving crewman states on Page 20 that he saw the pilots attempting to secure the PCLs. I guess the vibrations prevented them doing so in time. Hence my comment about doing it really quickly - in ground resonance the amplitude and severity of the oscillations increase very rapidly so if you have dithered whilst trying to diagnose the problem, you are already on your side.

Only good awareness amongst the Wessex fleet about the problem and good training by the RAF prevented me from ending up, like them, as the owner of a big pile of scrap.

[The Sultan]

Crab,

As Lonewolf stated this is not a common event and the report indicated there was no warning prior to the incident. You have to allow 1-2 seconds to realize their is a problem before anyone can be expected to respond. The pilot attempted to shut down the engines, but events over took them almost instantly. To get the result you put forward the crew would have had to know of the problem, prepared for it and done a hovering throttle chop with max collective and hope the rotor rpm dropped below the critical frequency before the oscillations became destructive. If the problem had been annunciated the best course may have been to ditch.

[[email protected]]

Sultan - I disagree, I have encountered full on ground resonance in a Wessex and the early stages in Sea King - there is enough time to do something about it but you need to have been trained to recognise and deal with it.

As soon as they landed and experienced the 'padding' that precedes GR, they should have lifted to the hover - if the oscillations stop, that is when you consider a running landing or a low hover throttle chop.

How much GR awareness is there amongst the Blackhawk users? If it is a very unusual occurrence on that aircraft then it is understandable why they didn't recognise it and act quicker.

[SASless]

I shall agree with Crab on this one....yes I know.....mark it on the calendar as it is somewhat rare.

In my past I flew the Hughes 269/TH-55, a very limited exposure to the H-19 (Whirlwind to our British friends), the H-34/S58T, and the Alouette III which all were candidates for the Fastest Self Destruction Competition.

Starting in primary flight school we were exposed to the dangers of Ground Resonance....those of us who were flying the TH-55 and not the H-13 or H-23 had to know about.

Recognizing the onset of Ground Resonance is the most important issue....knowing what it feels like (we had demonstrations of it in our training) and then immediately doing as Crab said....Pick up to a Hover or shut down the engine(s) and decrease the Rotor RPM as quickly as possible are the two options.

It is not the shut down of the engine that makes the real difference....it is the Rotor RPM and the Angular out of balance of the Rotor system.....changing the resonance and reducing the forces generating the resonance is key.

In the video....the second Hughes 269/300 clip shows how the quickly the resonance dissipates after lifting off the ground as the aircraft is free of the surface and the feedback from contact with the surface

The chinook clip shows the aircraft was tied securely to the ground and the aircraft landing gear struts were unable to function as designed......and despite the Test Engineers shutting the engines off.....there was no way to slow the blades quickly as the aircraft did not have a Rotor Brake.

https://www.youtube.com/watch?v=SPHoumJvVtQ

[Droop Snoot]

automatic blade folding


Blade fold is driven by electric motors in the spindles, not hydraulically by the dampers..

The BH has independent dampers. The NH has all 4 connected to a common reservoir under the beanie. Not familiar with the system, don't know if a broken line can pump all 4 dampers dry.

[JimEli]

Blade fold is driven by electric motors in the spindles, not hydraulically by the dampers..

The BH has independent dampers. The NH has all 4 connected to a common reservoir under the beanie. Not familiar with the system, don't know if a broken line can pump all 4 dampers dry.

Yes, electrical motors are used to fold the blades. But it is my understanding to properly position/restrain the blade the dampers are hydraulically extended to the max-lead postion.

[Droop Snoot]

Yes, electrical motors are used to fold the blades. But it is my understanding to properly position/restrain the blade the dampers are hydraulically extended to the max-lead postion.

Could be true, not sure, but don't think so

I know it is true for some hydraulic blade fold systems.

Someone is bound to chime in with the definitive facts!

[JimEli]

FWIW

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/900x675/fold_c067002ae02c20c7de62baca07b085b819f57157.jpg
lead/lag at maximum

[SplineDrive]

FWIW

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/900x675/fold_c067002ae02c20c7de62baca07b085b819f57157.jpg
lead/lag at maximum

This photo nicely shows the damper, with unequal areas on either side of the piston, pushing the blade forward to the lead stop under hydraulic pressure so that a pitch lock can engage the pitch horn (visible on the left hand side of the image). There is no visible accumulator to compensate for changes in fluid volume with temperature, etc. but there is a hose leading off the damper, presumably to a central accumulator. May not be practical to design internal valving that would stop the system from draining from a damaged hose for every leak rate.

Blade fold is a necessary, but absolutely horrible thing for a rotor design.

[ShyTorque]

Sultan - I disagree, I have encountered full on ground resonance in a Wessex and the early stages in Sea King - there is enough time to do something about it but you need to have been trained to recognise and deal with it.

As soon as they landed and experienced the 'padding' that precedes GR, they should have lifted to the hover - if the oscillations stop, that is when you consider a running landing or a low hover throttle chop.

How much GR awareness is there amongst the Blackhawk users? If it is a very unusual occurrence on that aircraft then it is understandable why they didn't recognise it and act quicker.

I flew the Blackhawk S-70 for four years. Unlike with the Wessex, I have no recollection of the type having a ground resonance tendency. I think Sikorsky had already learned their lesson.

[[email protected]]

I flew the Blackhawk S-70 for four years. Unlike with the Wessex, I have no recollection of the type having a ground resonance tendency. I think Sikorsky had already learned their lesson. That is sort of my point, if the aircraft doesn't have a tendency then crews don't know about it and don't react correctly on the one occasion it does happen.

[JimEli]

FWIW, in 2005 it was known "the MH-60S rotor dampener lines are relatively soft and easily penetrated, which increases the risk of severe ground resonance problems on landing."

[Droop Snoot]

This photo nicely shows the damper, with unequal areas on either side of the piston, pushing the blade forward to the lead stop under hydraulic pressure so that a pitch lock can engage the pitch horn (visible on the left hand side of the image). There is no visible accumulator to compensate for changes in fluid volume with temperature, etc. but there is a hose leading off the damper, presumably to a central accumulator. May not be practical to design internal valving that would stop the system from draining from a damaged hose for every leak rate.

Blade fold is a necessary, but absolutely horrible thing for a rotor design.

Jim and Spline...

I stand corrected. it sounds like the damper positioning system is a passive function, I haven't found any reference to valves. The accumulator is inside the shaft extension.

As you know, the USCG eliminated the blade fold hardware some time ago.

According to the investigation report, the damper hose was crushed at some point, then suffered a progressive failure of the braid wires prior to rupture and catastrophic leak.. So it is possible it could have been found during maintenance, but it would have been improbable.

[The Sultan]

Sultan - I disagree, I have encountered full on ground resonance in a Wessex and the early stages in Sea King - there is enough time to do something about it but you need to have been trained to recognise and deal with it.
As soon as they landed and experienced the 'padding' that precedes GR, they should have lifted to the hover - if the oscillations stop, that is when you consider a running landing or a low hover throttle chop.
How much GR awareness is there amongst the Blackhawk users? If it is a very unusual occurrence on that aircraft then it is understandable why they didn't recognise it and act quicker.

From the report:

13. The pilots were attempting to follow the NATOPS emergency procedure by pulling the PCLs for .. Unusual Vibrations on Deck", but were unable to do so based on the violent shaking of the aircraft and the centrifugal forces resulting from the yawing motion of LT 616. The PCLs were most likely not secured prior to the aircraft rolling off the flight deck. [Findings of Fact 63, 93]

Apparently pulling pitch is not an option per the NATOPS. As stated the procedure could not be accomplished due to excessive vibration. This does highlight the benefits of collective mounted throttles like on Bells.

Bottom line there should not have been a single unenunciated failure mode that could lead to ground resonance. The question now is why did NAVAIR allow this design to proceed?

[[email protected]]

Apparently pulling pitch is not an option per the NATOPS. As stated the procedure could not be accomplished due to excessive vibration. This does highlight the benefits of collective mounted throttles like on Bells. Yes, sometimes blindly following the rules isn't the best option - airmanship always trumps rulebooks in such scenarios. I also wonder if they were trying to follow the checklist rather than doing it from memory - that might explain the delay.

The NATOPs procedure may have been written for experiencing vibrations on start up rather than on landing.

[JimEli]

Yes, sometimes blindly following the rules isn't the best option - airmanship always trumps rulebooks in such scenarios. I also wonder if they were trying to follow the checklist rather than doing it from memory - that might explain the delay.

The NATOPs procedure may have been written for experiencing vibrations on start up rather than on landing.

FWIW,

The NATOPS procedure for Unusual Vibrations On Deck is singular in its response:

1. Collective — Lower.

2. PCLs — OFF.

3. Rotor brake — Apply as required.

The procedure is a Critical Memory Item (CMI), and the steps are expected to be performed immediately, without reference to the checklist.

It probably considers the complicated nature of shipboard operations and the severe safety implications of a helicopter suddenly becoming airborne on a busy deck.

However, a NATOPS FM copy I reviewed includes the option of going airborne in a previous section referencing ground resonance (possibly in an unstated reference to non-shipboard operations):

“If ground resonance should occur, primary consideration should be given to getting the helicopter airborne. If this is impossible, immediately reduce collective pitch, place the PCLs to OFF, and apply the rotor and wheel brakes.”

Since the Navy’s Command Investigation only addresses a potential equipment modification, I assume becoming airborne is not an option:

“Helicopter PCL location in the upper center console is not ideally located for quick securing of the engine in an emergency. Recommend NA VAIR direct a review of emergency procedures and equipment to determine whether it is possible to enable a quicker and easier PCL response during a ground resonance event.”

[[email protected]]

Thanks Jim - seems like there might be mixed messaging in the books

[Droop Snoot]

From the report:





Bottom line there should not have been a single unenunciated failure mode that could lead to ground resonance. The question now is why did NAVAIR allow this design to proceed?FMEA or design assessment reports or related documents could hold the answer to that question.

The braided hose has redundancy, but the fittings do not.

The Navy Command Report has some interesting items that reflect on the assessment of the design…

· Hose is an “on condition” part.

· Hose is inspected at various intervals.

· Hose replacement rate is about 1 per aircraft per year.

· The mishap aircraft had 2 hose changes in the month prior to the event.

· “Mechanical damage (flattening) of steel braid strands on a damper hose would not be evident during any external inspections.” The braid is covered by a chafing guard, and it therefore not visible.

· A one time replacement of all fleet hoses was recommended.

· Fleet inspections apparently have not been changed.

[SASless]

Sultan noted the Accident Report did not discuss the Engine PCL's being on the Overhead Panel being a detriment as compared to the Collective mounted Throttles on Bell Helicopters.

This does highlight the benefits of collective mounted throttles like on Bells.

Many aircraft have "Levers", "Buttons", "Knobs" instead of the Bell Collective Throttles.

With the advent of electronic digital control systems we see new and different methods of controlling the Engine(s) as compared to legacy systems using electro-mechanical means.

I have flown several different aircraft with various approaches to Engine Control....and have seen advantages and disadvantages in all of them.

So what should be the determining factor in which design method is employed?

One look at a V-22 Thrust Lever and I shudder to think what engineering issues and human factor issues would have to be confronted to move the PCL's from the overhead Panel to the Thrust Lever.

As it is now....they are moved to the Fllght position not touched until Shutdown of an Engine or Engines.

[Lonewolf_50]

Sultan noted the Accident Report did not discuss the Engine PCL's being on the Overhead Panel being a detriment as compared to the Collective mounted Throttles on Bell Helicopters. Sultan may not be aware of how the T-700 is controlled and governed in the Seahawks and Blackhawks, so I'll be happy to attribute that to Sultan's usual Bell Bias.
I've flown twist grip throttles on TH-57 and Hueys, the center console mounted ECL's in SH-2F's (which can be inadvertently bumped out of the "fly" position, don't ask me how I know that), and the Sikorsky overhead PCL (also used on the CH-53E, can't speak from memory as regards the S-61 / Sea King but I suspect they do also) .
They are fit for purpose.
Also, as you noted:
As it is now....they are moved to the Flight position not touched until Shutdown of an Engine or Engines.
This is from old memory...
If you have an inflight engine malfunction, you often move the malfunctioning engine's PCL out of fly and either take it to idle, shut it off, or retard it so that it's about 10% below the good one. (Depends on the problem, see your local NATOPS manual for details).
The ECU Lockout feature allows the crew to bypass the electrical control of the engine governor while retaining the load demand spindle / HMU based governing to keep the Nr in pretty close limits (though you will usually see a little bit of lag in getting back to 100% Nr if you make a lot of power changes).

[SASless]

Bad Vibes from Sultan.....please say it ain't so.:=

As the V-22 is a Bell-Boeing Design....can he actually say Bell products have Collective mounted Throttles?

Boeing calls the "Collective" a "Thrust Lever" owing to its aircraft being Tandem Rotor designs for the most part.

In the Tilt Rotor it is also called the "Thrust Condition Lever".

Engine controls are called "Engine Condition Levers" as they were called on the Chinook.

From an Osprey Test Pilot.....when told of this thread.


Ground resonance is not a problem. Very rigid inplane rotor system coupled with rigid fixed wing type gear. No oleos nor dampners, hydraulic spring absorbers on gear. Throttles are Engine Condition Levers (ECL'S) on center forward overhead panel. Totally electronic. Full forward to fly and forget. TCL (thrust condition lever) controlled by left hand with forward for increasing power, after for decreasing. Acts like a collective in helo mode and throttle in airplane mode. All controlled through triple redundant flight controlled computers. Pilot has NO mechanical linkage to engine or flight controls. All fly by wire. Pilot is one of 4 voting members and is subject to being out voted on routine basis.

[JimEli]

During a commercial airliner takeoff, the PF usually has his hands on the throttles while the FO backs him/her. Just saying.

[212man]

During a commercial airliner takeoff, the PF usually has his hands on the throttles while the FO backs him/her. Just saying.
A slightly mixed up statement I think. FO and Capt can both be either PF or PM, however, many/most airlines state that only the Capt can decide whether to abort the take off. So, if the FO is the PF it is SOP that the Capt also guards the throttles until V1, so that he can abort the T/O without the delay of instructing the PF to do so.

No idea what this has to do with the incident in question - are you suggesting the PM/PNF should hold the ECLs during T/O and Landing just in case there is ground resonance (or TR failure)?

[JimEli]

A slightly mixed up statement I think. FO and Capt can both be either PF or PM, however, many/most airlines state that only the Capt can decide whether to abort the take off. So, if the FO is the PF it is SOP that the Capt also guards the throttles until V1, so that he can abort the T/O without the delay of instructing the PF to do so.

No idea what this has to do with the incident in question - are you suggesting the PM/PNF should hold the ECLs during T/O and Landing just in case there is ground resonance (or TR failure)?And low/high-side failures (etc.) and when conditions do not allow OEI HOGE and in certain environments.

Just food for thought.

Before mocking, contemplate if it may have saved this aircraft and crew. I doubt the Navy's investigation reccomending changing the location of the H-60 PCLs would ever happen.

I wouldn’t suggest it without it being SOP and prior training. I don't expect the thought to be well accepted either, the industry as a whole has a hard enough time getting a PF to give the NFP a proper takeoff or pre-landing brief.

[SASless]

Having enjoyed a wild ride in a helicopter that had lost three pockets of one forward rotor blade....providing lateral vibrations with a force and magnitude to cause the Cyclic to leave black and blue bruises on my inner thighs....it took a bit of doing before we reached the Engine Condition Levers and pull them back to shutdown the engines after landing.

Whether they are overhead or down on the center console as in my case....reaching for the things can be awfully hard to do.

If a hand was firmly grasping the Levers prior to it all going bad...perhaps if the hand was not dislodged....getting the Levers moved. might be a lot more probable.

The Question is how often do these events occur?

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No idea what this has to do with the incident in question - are you suggesting the PM/PNF should hold the ECLs during T/O and Landing just in case there is ground resonance (or TR failure)? When I was PM in a Sea King, my hand was on the SSLs in the roof panel matching Tqs and ready for problems in critical flight regimes.

[JimEli]

When I was PM in a Sea King, my hand was on the SSLs in the roof panel matching Tqs and ready for problems in critical flight regimes.

Crab, in fact the idea first entered my head after seeing the Green pilots down the street.