AIB

Mx: don’t release a jet to fly if you shouldn’t

Pilots: don’t turn into a dead engine

Pounded into heads for years...yet it still happens.

Jesus

I just read the whole thing.

The SIB is significantly less fun to read.

Thank you for posting this.  I just realized I walked through that plane when it was with the TN ANG.  I thought it was strange on the airshow ramp in Memphis with the modified radome and spoke to the crew who shared the history of its WC-130 conversion.

Turning into a bad engine and stalling was, admittedly, the final link the the sequence, but..
I'm not sure what that kind of negligence warrants...but it has to be something, as it helped kill 9 people who trusted their maintainers...

All 9 people also trusted that the pilots were competent aviators.

When studying mishaps like this, we often refer to the Swiss cheese model. Only very seldomly do all the holes line up, but when they do, it is with catastrophic results.

The pilots screwed up, no doubt about it. But the plane should never have been flying to begin with.

What’s is worse, incompetence or negligence?

Even with the maintenance deficiencies the crew had ample opportunity to prevent the disaster.    Seems the Flight engineer was kinda inexperienced.   Even after they took it airborne this was plenty survivable.  In the end it seems piloting skills was lacking for some reason.   CRM was terrible.

And turning into a dead engine is not always critical.  Using the wrong rudder at the wrong time however.........!!!!!    Among other things in this incident.  Evansville!!

Me:   6000 hours as a Herc flight engineer.

I’ve been out of the Herc for a few years now, but the 1 job of the engineer on takeoff roll is to set power and cross-check the engine stack, right?

Especially considering the tail was grounded for maintenance for a few weeks to work on the specific engine that failed, you’d think it would garnish extra attention.

Not really the FE's job on a Herc to set takeoff power.   Throttles are too far forward.   They can set climb power and cruise but that's after takeoff.   Both pilots monitor during takeoff throttle setting.  FE monitor while they advance throttles and establish a stable power setting?   Sure thing.    The FE's #1 job on t/o is to monitor the eng instruments, plus the overhead panel.   Also the pilot not flying monitors the eng instruments as well.

In this case I'm not sure why this FE did not call "Reject."   Either he missed it or just was unsure of himself.  I mean this was a huge roll back that should have been noticed.   Even the pilot could have rejected based on the aircraft veering during takeoff roll.   A lot of WTF in this one.

It was mainly there for fuel cell work.   The eng/prop issue was incidental from the precious flight.   And remember it was not scheduled to go to the Boneyard until after it arrived in Savannah.

Yeah, I just remember the eng adjusting the throttles, calling “power set”, etc.

There is no excuse for the aircrew’s actions. An abort could have seemingly been safely accomplished. It was also a perfectly flyable airplane if you remember the basics: min controllable airspeed, and which direction to turn. We used to say “raise the dead”.

I questioned why the pilot did not abort the takeoff himself when it was obviously an asymmetric thrust issue during takeoff roll.   I read that the CVR tapes would answer that question.   Any insight since I do not have access to the CVR recordings/playback?

I haven’t listened to the CVR. Honestly, I’m not sure I have the stomach to.

When this happened I was sadly not surprised. The PR Army NG UH-60’s we came across had such bad corrosion problems and were so poorly maintained that half their aircraft were grounded before the hurricane even hit, and the other half were damaged from being left out in the elements.  As my PR buddy says....that’s what happens when you have a people more concerned with dancing and fucking than working. Sucks for all involved.

This is not uncommon with aircraft that are exposed to the salt air environment.   During my time at Depot I saw several C-130s come in for Depot maintenance but once they got to opening them up found corrosion so bad they just basically grounded them to never fly again as repairs were not cost effective.   One from PR and one from Patrick AFB.    The HC-130 from Patrick was flown home from the desert specifically to go to depot.  Up till that point it was operational.

Wear and tear in that environment will be greater, but most of their issues were from a lack of Mx.

I have a theory. Don’t fly on any airplane operated by outfit known as”PRANG”.

I read the entire report.  Very interesting, even to a layman like me.

I understand the need to investigate mechanical, psychological, health, toxicology, communication, experience, etc.

But what does this mean?

e. Lifestyle
There is no evidence to suggest lifestyle was a factor in the mishap.

These are required portions of the investigation and report, and ruling them out is just as important as finding the root cause.

So many of the flight control inputs I saw in that report -- from the rudder "dancing" (the indecision about which rudder input to make), to the failure to "raise the dead", to the turn into the dead engine, and finally the big rudder-induced skid into the dead engine -- seem like what I'd see from a new pilot or a non multi-engine rated pilot.

Not what I'd expect from someone of that pilot's training and experience level.  Those are usually the spears that get thrown at the "centerline thrust" fighter dudes.

That's a rough read.

(I spent several years as a Com/Nav tech on 130J's and did the Coronet Oak mission to PR a couple times)

Sadly, I have seen far too many maintainers display the lazy attitude of "good enough", particularly with some AD sq's I worked with. During some brief trips to Muniz, I got the impression that it was certainly an island culture base, kinda lazy.

Hopefully same changes happen to the wing there to change the culture.

An A-10 pilot flew his jet into the side of a mountain years back. It was ultimately deemed a suicide.

Nothing of the sort was a factor in this mishap.

Sadly I have seen far too many pilots and instructor pilots display the lazy attitude of "good enough" when it comes to EP training and evaluation.

I know absolutely nothing about aviation maintenance and I'm just a lay man reading this. I never would have thought that one percent deviation in Power on a turbine engine could be so critical.
Hard to believe their top pilot is the one who flew It to the Ground.
Hopefully they learn from this and don't allow it to be repeated.

Most engines a one percent deviation would not make much difference.

Its been a year since i flew a Herc so i will try to explain it as I recall the systems. Also I haven't read the AIB findings yet but I can guess what happened.

The c130 engines are a bit different.  It is a "constant speed" turbine.  It runs at 100% rpm all the time. (Except when in "ground idle", which isnt relevant here.)

When the power is advanced in a constant speed engine more fuel is added, the engine makes more torque and the propeller blade angle changes, but the engine speed remains the same. 100% rpm plus or minus a little bit.

The engine needs to be running at 100% or it is in danger of not running at all.  As I recall at 96% percent the engine will shut down entirely.  I have had exactly that happen more than once. The valve housing (propeller governor) failed in flight causing the engine to shut down spontaneously.

An engine not making correct rpm during a test run is a sick engine.  They are a complicated machine, requiring competent mechanics and crew or it will bite you in the ass.

As I read it, when feathered, the torque and rpm "indications" fluctuated quite a bit. So, the best pilot in the unit makes "seemingly indecisive" back and forth rudder inputs after feathering? Could it be that he had surging yaw issues at/near/after feathering? Surprising reaction regardless.

The fact that there was no abort called with the rpm loss on takeoff is shocking too. I see that as a "you had one job" scenario to the pilot monitoring.

RIP to all.

What lifestyle aspects would DQ someone from be certified?  What lifestyle aspects would be considered a contributing factor to a mishap?

I'm genuinely curious about this.

OK, but wouldn't that fall under 'medical?'
How is suicide a lifestyle?  I know you're not suggesting that, but how is 'lifestyle' relevant in the A-10 incident.

Read up on the family factors in the NY Times article -- that's the kind of things they're talking about.

https://www.nytimes.com/1998/12/25/us/airman-s-flight-to-his-death-is-laid-to-mental-anguish.html

https://en.wikipedia.org/wiki/Craig_D._Button

I honestly can’t see how turning into the dead engine could have caused this accident.

Is this still taught in the military?

On a large turboprop airplane, there’s plenty of thrust.   How you manage that thrust is key.  The rudder must be managed judiciously, with the trim, pitch and configuration carefully controlled; or that excess thrust becomes your undoing.

Interesting read thanks for posting.

Did you read the report?

It wasn't "just" turning into the dead engine -- it was the back and forth indecision about what to do with the rudder, combined with failing to bank away from the dead engine, as well as the overall failure to follow the engine failure on takeoff checklist (specifically with the flap config).

But all of those mistakes probably wouldn't have caused the crash if the AC had not planted a boot-full of rudder into the dead engine.

And, yes, these basic things that are taught in light twins are still wholly relevant in a Herk.

You're on and off on some of your comments.

The propeller is what controls the engine RPM during normal operation.  Yes it is a constant speed engine but only more critical in the flight range.  RPM limits are 98 to 102%.  This is mostly due to tach gauge error however.   I think the true on speed is 100 +/- .5%   but again this is controlled by the prop.   When you add throttle the engine tries to speed up due to increased fuel flow which increases turbine temps.  However to maintain the same speed the propeller increases blade angle to attempt to maintain the same rpm.   The increased blade angle also increases prop thrust.

The problem with a lower RPM is the acceleration bleed valves on the compressor section.  If they open at lower RPMs this will lower compressor pressure significantly.   They are held closed at 94% RPM by the Speed Sensitive Valve.

Propeller RPM is adjusted/controlled by the Valve Housing within the Prop assembly.   Which is what was being worked in by the MX guys.   They were attempting the adjust the mechanical RPM speed of the propeller.  It the eng/prop are not running at 100% it will still operate fine up to a certain point however.   There are additional electronic controls attempting to get 100% RPM.   However it the RPMs are below the normal range then it's possible at some point during normal lower RPM settings they could get low enough for the Acceleration Bleed Valves to open which would cause a loss of power from that engine.   Loss of an engine in flight while critical is FAR from loss of aircraft control except under the worst possible combinations of conditions.   That is why the crews train with eng out conditions.

Even if the MX guys messed up this crew basically did everything incorrectly.

Based on what I've read even if the MX guys tweaked the Valve Housing one last time to get the better/closer to 100% operation there were still other issues with this engine/prop assembly that were not seen by the MX guys.   Something was causing the RPM to decay way below the normal operating limits even in the flight range.  The MX guys did not see this during their engine runs.    Could have been a Valve Housing issue or just as easily been some kind of Fuel Control or even Temp Datum problem.   Due to the damage from the crash we might never know that actual problem with that motor.   Doesn't matter at this point.

The crew let this issue spiral out of control in multiple ways.

A failure of the number 1 engine is going to cause asymmetric thrust issues - exacerbated when you are slow on climbout with the remaining engines operating near max power.  This condition is going to cause a roll and yaw into the dead engine.  It requires 5 or 10 degrees of bank and rudder away from the dead engine to stay straight and level.  Turning into the dead engine can cause the aircraft to exceed a critical sideslip angle, stalling the wing.  Additionally, removing rudder inputs away from the good engines can cause an excessive yaw rate which will also exceed the critical sideslip angle, and it sounds like this is what happened - exacerbated by the fact that the mishap engine went through a couple cycles of losing, and then regaining power.  Losing either of the outboards makes this a more critical situation than losing either of the inboards.  Both are perfectly recoverable however, given that you don't do stupid shit.

Sad, just sad.

Watched a simulator recreation of the C-5 accident years ago.

Different circumstances but same piss poor CRM.

Just so some of you non pilots understand, you can safely turn into a
dead engine, but you need to be flying at a safe airspeed with proper trim.

Had to shut the #1 down on the King Air a long time ago, plenty of left turns
getting back to the airport. Not a big deal.

The part in red is the key part. From what I read in the report, the crew had neither.

I've had a "few" engine failures in twins where I had to turn into the dead engine.

Having never flown a 4-engine plane, I can't speak for the aerodynamics of losing an outboard engine, but can imagine it changes the moment arm tremendously, but having speed and properly trimmed, whether it be by trim wheel or foot/hand are the 2 important factors in surviving the failure.

The #1 and #4 engines are way out there on the wings of a Herc. Losing one of them in cruise is not nearly as significant as losing one at rotation.

3 engine and 2 engine minimum controllable airspeeds are definitely a thing.

For correctness' sake, the term "trimmed" has to do with balanced control forces; ergo, if you removed your hands or feet from the control, would the surface remain in its present position (if trimmed) or move to some other position (if not in trim).  You don't "trim" a control by application of pressure on it with your hands or feet.

The term "coordinated" is what describes having the ball centered and the airplane moving in the same direction it is pointing.  This is what you are doing when you push on the rudder pedal when there is a failed engine and asymmetric thrust.  If the airplane is skidding or slipping, then the airplane is "uncoordinated".

The critical flight control issue when dealing with a failed engine in a multiengine aircraft with asymmetric thrust is coordination, as it keeps relative wind (and thus lift) the same on both wings.

In the Herc world some of these number/procedures are for the worst case scenario.   For instance losing an engine at or near takeoff is the most critical due to multiple problems.  No 1 engine failure with a prop on NTS gives the most drag.   In other words it's not feathered.   The 5 degrees bank angle away from the bad engine is also based on having to keep the opposite outboard engine at a higher power setting.    For lighter operating weights and/or colder temps it may be advisable to reduce power on the opposite side to lessen the adverse yaw.   For a Herc that is at or near maximum operating weight though you may need all the power to remain airborne while accelerating the 3-engine climb speed.

The Herc in this accident had ample power to reduce thrust on the opposite engine to aid in recovery.    But as the report stated this crew basically did nothing correctly.

"Coordinated" and "Zero sideslip" are two conflicting terms in multi-engine with an engine out.

Coordinated is as you say, ball centered. However if you carry the one wing high, say 5° you will be in a side slip if the ball is centered... Instead, you seek to keep the ball out of center with no turn. How much out? Matches the bank angle you are using and to the wing low side.

In this case it is moot as the aircraft commander never got the situation under his control. In his defense this was not the Black and White engine on takeoff fail we practice! This was the grey area of partial power, what's not right here, power back up, huh?

Completely agree, I was just referring to the terminology and the misuse of the term "trimmed", which doesn't describe either condition.

Seems pretty clear to me.   Power unrelated to throttle position.  Or uncontrollable prop.    Either one it's CAN it.    All practiced in many ways.   They did so many things incorrectly it baffles the mind.

Something that hasn't been brought up that much is the RECENT flight experience of the crew.  The pilot in command was well qualified, but had only flown a single sortie in the previous 30 days, while the copilot had flown 3 (for less than a total of 5 hours) in the last 30 days, none in the 60 days prior to that and a total of less than 20 hours as a pilot in the C-130 per the report.  The pilots' lack of recent flying time doesn't give me confidence that they were actually "proficient" in the aircraft.  "Rusty" is the way it would normally be described, and is (IMHO) likely a factor in the delayed recognition of the problem as well as the confusion and interrupted habit patterns (not completing the checklists, for instance) which together pushed this crew into a corner that they were ultimately unable to get out of.

Mike

I understand that reference.......in part thanks to PO Prune!

In another place I'm seeing people defend these guys.   The pilot was referenced as one of the best in the unit.   The FE was also praised as a great engineer.   I am also hearing about CRM issues within this unit.   I mean the whole reason CRM was being taught was/is not being followed well in this unit.   I know people who watched the crash depiction video with embedded CVR data.   And was told(or I have read) it was hard to not holler at these guys during the playback at all the boneheaded mistakes these guys made.

And yes these 3 upfront, especially the Co and FE, were not very experienced.

FYI I am not privy to the SIB data.

It was hard not yelling at my monitor READING the report. Sadly none of the conclusions about causal and contributing factors will come as a surprise to anyone who has seen PRANG operate up close.

Some info I got was indirectly from an active duty Guard advisor who used to fly with them.

(EDIT) Disregard, misread previous post

I used to work for an airline, that merged with another airline from PR.  My experience was that "standard" meant something totally different on the island, than it did in CONUS.

Because is doesn't matter for the purpose of determining cause. The crew was qualified and current.  No rules, regulations, or laws were broken.

Maintaining yourself at some point becomes an individual responsibility.  Your skill, knowledge, proficiency, etc. is yours.  Just like a pilot is expected to report medical issues to the flight doc, everybody in the military is expected to meet some physical fitness standard, etc, etc.  Nobody would defend a pilot who shows up to fly drunk by saying it was not his responsibility to stay sober!

If you do not possess the skill or proficiency required it is up to you to speak up.  An evaluation or checkride only determines if you are capable of meeting the standards, not that you always will.

It's a pet peeve of mine when people try to downplay individual responsibility in crashes.  There are a bunch of innocent people dead because the two pilots did not properly execute an engine failure on takeoff - the single most studied/briefed/practiced emergency in any multi engine airplane.