Shell 77, the KC-135 that crashed in Kyrgyzstan, has concluded pilot error/mechanical failure

First a bit of disclosure. The SIB (Safety Investigation Board) has released a classified briefing about the cause of the Shell 77 crash, which I have received a copy of. Also to note, an FCIF (Flight Crew Information File) was released after the crash that was FOUO, and will not be released to the public. Finally, an AIB (Accident Investigation Board) about the crash will be the declassified version that has not been released to the public, but is in the military world right now. I have also heard the audio from the cockpit voice recorder, which colaborates the SIB's findings, sort of.

**One question I will NOT answer is where or who I recieved the SIB and FCIF from, as it is classified**

Per AFI 91-204, the following is privileged information:

3.2.1.1. Findings, conclusions, causes, recommendations, analysis, and the deliberative process of
safety investigators. Diagrams and exhibits if they contain information which depicts the analysis
of safety investigators. This includes draft versions of the above material.
3.2.1.2. Information given to safety investigators pursuant to a promise of confidentiality (paragraph
3.4.).
3.2.1.3. Computer generated animations, simulations, or simulator reenactments in which safety
investigator analysis is incorporated. Animations made exclusively from recorder data (including
Military Flight Operations Quality Assurance data) are not privileged.
3.2.1.4. Photographs, imagery, and animations that reveal the deliberative process of the board,
including photographs with markings.
3.2.1.5. Life Sciences Material that contain analysis by a safety or life sciences investigator.
NOTE: 72-hour histories, 14 day histories and interview narratives by Medical Officer are only
privileged if privilege was granted.

Ok so here's what movement has happened so far. The first thing to release was an FCIF to the 135 with "lots" of focus on flight control section dash-3 stuff, basically saying review before flight. Now, a huge emphasis was put on the rudder, horizontal stab trim actuator, basically flight control systems with no reason as to why they were releasing the FCIF. This was the first indication that it was a mechanical failure of a flight control system...but theres more.

After the FCIF was released, and the Four Star was briefed on the cause the families were formally briefed by the SIB. The SIB (secret) report was then released to all tanker crews. This is where it gets interesting. The SIB doesn't come out flatly and say pilot error. But there's some weird stuff in this report that I've never seen in a SIB briefing. For example, in the AIB (declassified version, not released to public yet) they do not call it flat out pilot error, but place emplasis on the flight manual in the FCIF and further talk of training flights tell us the crew did make a mistake (wrong reaction). A mechanical problem with the Rudder followed by an incorrect choice by the crew. This is confirmed by the tapes too. But here's what the SIB says (paraphrased a little cause of classification)..

During the climb out of Manas AB, the PCU failed and they had been flying the jet manually due to the rudder power circuit breaker being popped open. On the cockpit voice recorder, the co-pilot is heard very clearly saying that it was tiring work and he's getting tired too easy from having to use manual rudder control. So they discussed the problem and decided on a course of action that broke a critical dash 1 warning, regarding resetting the rudder power circuit breaker. Consequently, they reset the rudder power circuit breaker while the rudder was being applied in the full deflection by the co-pilot. Well as you could guess, the rudder slams over hard, rips off the tail, and sent the tanker into a Dutch roll, subsequently breaking apart the aircraft.

So if we look at the entire events and how they unfolded, mechanical failure of the PCU and the rudder power were the culprits that led the crew to make the human/pilot error of resetting the circuit breaker with the rudder in full deflection. The crew did everything by the book, with the exception that they forgot about the warning talking about rudder deflection and resetting the breaker. The Co pilot had the jet, the AC was turned around talking to the boom operator about the location of the circuit breaker and giving a job briefing. As soon as the boom operator (alledgely, although unclear, but thats part of a booms job) reset that circuit breaker, the crew of Shell 77 sealed their fate. The AIB is not calling it flat out pilot error, because of it being a sensitive area with the families and such. However, the classified SIB does every thing it can short of saying "PILOT ERROR" to place the blame on the captian. But they even went a step further in the report, and did something absolutely uncalled for, spinning me into a world of fumes.

There's a section after the investigation portion of the report that states our Aircraft Commander of Shell 77 was Q3'd (Unqualified level 3) by an Evaluator Pilot during a non-checkride flight because of the handling of the Student Demo portion of the flight, appx 3 months before the deployment to Kyrgyzstan. Really? There gonna smear his name in the classified version, and put out there trying to say hes a less than average pilot and aircraft commander?


The AIB release has been delayed a few weeks for what they are calling administative reasons. But the two versions differ a bit in story, which is bull crap if you ask me.

IM STILL FUMING!!!

reply to post by boomer135


There is no reason to bring up the Q3 issue. That has absolutely nothing to do with the Mishap Flight, and shouldn't be included. Unless it was something that he had done repeatedly, that had a direct impact on the MF, then there is absolutely no reason to bring it up at all. I've noticed lately the Air Force has jumped straight to pilot error, and been blaming the pilots a lot more than in the past.

What I'm wondering is if the PCU is similar to the one used in the 737s. They had problems with those for several years, which led to a United crash in Colorado Springs, and a USAir crash in Pennsylvania. That was rudder reversal, but I can see a PCU failure happening too.

As soon as you said "PCU" I closed my eyes and said "Oh #" and knew exactly what happened. I didn't even have to read farther, but when I did I was dead on as to what happened. We saw that happen a few times on the ground (thank god), and that rudder deflects HARD. I'm surprised it didn't cause damage to the rudder when it happened.

Is there any chance that you will post documents? If what you have described is accurate, I can't wait to read more.

reply to post by ChaffandFlares


Not until the board releases their public report. That could be tomorrow, or it could be months from now.

Who was the co-pilot - there were 2 captains and a tech sgt.

Is the boomer a tech sgt?

Then there are two captains, one male and one female, but in the report "the co-pilot mentioned he was getting tired" and then Zaphod mentions the pilots Q3 saying "he".

Just wondering if there was any physical issue with the co-pilot getting tired too quickly?

Is the protocol to get the aircraft back to base asap or try and resolve the issue and carry on with the mission?

Doesnt matter I suppose, a sad loss in any case.

reply to post by IamSirDrinksalot


The Aircraft Commander (AC), was the one in question with the Q3. That was Capt. Mark Voss, the copilot was Capt. Victoria Pinckney, and the boomer was Tsgt. Herman Mackey.

It wasn't that she was a woman, the rudder in manual mode on any large plane takes a lot of strength.

It depends on the problem. Some the crew can troubleshoot, or even fly the mission with the problem. Others, they try to get on the ground ASAP. The thing here is they would have had to fly for awhile if they decided to abort, because they don't have a fuel dump, and they were too heavy to land.

reply to post by boomer135


I flew tankers for 26 of my 28 years. Half in KC135s other half in KC10s with a stint in Caribous.

In the 135 I was an IP for 12 years and a CCTS instructor for five.

One thing I remember, and I checked my -1 to make sure.

The rudder PCU was "fail safe" to the powered mode. IOW it took electrical power to shut it OFF. Had the c/b been popped the rudder would have been in the powered mode, not manual, so the copilot would not have been stressed by flying in the manual mode. Resetting the c/b would have only allowed the rudder to be put in the manual mode by turning off the switch on the center console.

Further, lacking some sort of asymmetrical thrust manual or powered would have been no different, little or no rudder input required.

Also, once the airspeed got above 250 KCAS the rudder power would have been reduced to prevent over controlling due to high rudder PCU pressure.

In short, the analysis by "boomer135" just doesn't pass the "smell test" at least not from my perspective. I suppose it's possible that the 135 was modified to make the rudder power a "fail fail" system so if the control power was lost the rudder would revert to the manual mode. But I'd like to see some documentation about that modification, i.e. TCTO #

I would welcome a little more from the poster as to what his expertise and experience in the 135 he had.

reply to post by ROFCIBC


I know boomer, and he has established his credentials as far as I'm concerned. The information from him has always checked out, and I have no reason to doubt him now.

reply to post by ROFCIBC


If you click on Boomer135's user name on his posts it will bring you to Boomer's user page and his posts. I think if you read through his posts you will find all the info you need on whether he is legit or not.

ROFCIBC
reply to post by boomer135

 

I flew tankers for 26 of my 28 years. Half in KC135s other half in KC10s with a stint in Caribous.

In the 135 I was an IP for 12 years and a CCTS instructor for five.

One thing I remember, and I checked my -1 to make sure.

The rudder PCU was "fail safe" to the powered mode. IOW it took electrical power to shut it OFF. Had the c/b been popped the rudder would have been in the powered mode, not manual, so the copilot would not have been stressed by flying in the manual mode. Resetting the c/b would have only allowed the rudder to be put in the manual mode by turning off the switch on the center console.

Further, lacking some sort of asymmetrical thrust manual or powered would have been no different, little or no rudder input required.

Also, once the airspeed got above 250 KCAS the rudder power would have been reduced to prevent over controlling due to high rudder PCU pressure.

In short, the analysis by "boomer135" just doesn't pass the "smell test" at least not from my perspective. I suppose it's possible that the 135 was modified to make the rudder power a "fail fail" system so if the control power was lost the rudder would revert to the manual mode. But I'd like to see some documentation about that modification, i.e. TCTO #

I would welcome a little more from the poster as to what his expertise and experience in the 135 he had.

Real quick, my expertise is nowhere near yours when it comes to systems knowledge. I'd say you have a few more years on me sir! I was a boom operator for six years, mostly in Grand Forks, ND. I have around 2500 flight hours, a little over 1000 combat or combat support hours, About 750 instructor hours, and probably around 100 evaluator hours. I went through CFIC in 2003.

When it comes to the flight control systems and the points you bring up, I can't argue with your expertise. I'll just say that the analysis is only what I've read in the reports. That being said, if you look at how the plane broke apart and the sequence of events, most people in the tanker world I talk to came to almost the same conclusion as the boards did.

On that note, I'm trying to find a counter argument to your dash one reference and I simply can't find anything to argue. The American people will get a little taste from the accident board eventually.

reply to post by Zaphod58


Fine, so why not address the issues I brought up? A loss of power and the rudder reverts to the powered mode. The fact that the manual rudder is effective at high speeds. No mention of asymmetric thrust that would have required rudder input, manual or powered.

I didn't attack his credibility, just the facts he presented.

To use an old saying "Enquiring minds want to know".

boomer135
Real quick, my expertise is nowhere near yours when it comes to systems knowledge. I'd say you have a few more years on me sir! I was a boom operator for six years, mostly in Grand Forks, ND. I have around 2500 flight hours, a little over 1000 combat or combat support hours, About 750 instructor hours, and probably around 100 evaluator hours. I went through CFIC in 2003.

When it comes to the flight control systems and the points you bring up, I can't argue with your expertise. I'll just say that the analysis is only what I've read in the reports. That being said, if you look at how the plane broke apart and the sequence of events, most people in the tanker world I talk to came to almost the same conclusion as the boards did.

On that note, I'm trying to find a counter argument to your dash one reference and I simply can't find anything to argue. The American people will get a little taste from the accident board eventually.

boomer135,

First, I have not read, nor do I have access to any of the official SIB material. I was basing my comments on the sequence of events you posted, especially about the popped CB and the fatigue issue of one of the pilots.

Here are the things you posted that just didn’t make sense to me.

“During the climb out of Manas AB, the PCU failed and they had been flying the jet manually due to the rudder power circuit breaker being popped open.”

and

“Consequently, they reset the rudder power circuit breaker while the rudder was being applied in the full deflection by the co-pilot.”

As I pointed out if the CB was popped, the rudder would be in the power, not manual mode. So the rest of the paragraph about the rudder suddenly slamming over if the CB was reset just doesn’t make sense. Also, I can’t imagine a pilot having the strength to apply full deflection against the power mode.
If the pilots were fighting a powered hardover rudder and the CB reset made it revert to the manual mode, then it would be much easier to control. True there would have been a quick move away from whatever direction the rudder was in, but that would have been in the manual mode. One could surmise that extensive “rudder walking” might stress the vertical stabilizer to the point of failure.

Can’t speak to your -1 Warning reference regarding the PCU shut off CB as I don’t find that in my -1. There is a generic warning about resetting CBs more than once, which may be what you are referring to.

As for the Q3 for a student demo, there could have been a lot of reasons for that, some with no connection to actual aircraft control. Don’t know what they call SACR 60-4 now but something as innocuous as an inadequate briefing or debrief may have been involved. I remember when the KC10 blew up on the ramp at Barksdale and all the flying records of the crew that had last flown the airplane were collected for the SIB. Just part of their procedures.

reply to post by ROFCIBC


Because I don't have the access to the SIB that he does, not the flight experience that he has. I was a ramp rat, who dealt with a lot of types, not any specific type. So I'm not going to sit and refute the facts, without the experience to do so.

ROFCIBC

boomer135
Real quick, my expertise is nowhere near yours when it comes to systems knowledge. I'd say you have a few more years on me sir! I was a boom operator for six years, mostly in Grand Forks, ND. I have around 2500 flight hours, a little over 1000 combat or combat support hours, About 750 instructor hours, and probably around 100 evaluator hours. I went through CFIC in 2003.

When it comes to the flight control systems and the points you bring up, I can't argue with your expertise. I'll just say that the analysis is only what I've read in the reports. That being said, if you look at how the plane broke apart and the sequence of events, most people in the tanker world I talk to came to almost the same conclusion as the boards did.

On that note, I'm trying to find a counter argument to your dash one reference and I simply can't find anything to argue. The American people will get a little taste from the accident board eventually.

boomer135,

First, I have not read, nor do I have access to any of the official SIB material. I was basing my comments on the sequence of events you posted, especially about the popped CB and the fatigue issue of one of the pilots.

Here are the things you posted that just didn’t make sense to me.

“During the climb out of Manas AB, the PCU failed and they had been flying the jet manually due to the rudder power circuit breaker being popped open.”

and

“Consequently, they reset the rudder power circuit breaker while the rudder was being applied in the full deflection by the co-pilot.”

As I pointed out if the CB was popped, the rudder would be in the power, not manual mode. So the rest of the paragraph about the rudder suddenly slamming over if the CB was reset just doesn’t make sense. Also, I can’t imagine a pilot having the strength to apply full deflection against the power mode.
If the pilots were fighting a powered hardover rudder and the CB reset made it revert to the manual mode, then it would be much easier to control. True there would have been a quick move away from whatever direction the rudder was in, but that would have been in the manual mode. One could surmise that extensive “rudder walking” might stress the vertical stabilizer to the point of failure.

Can’t speak to your -1 Warning reference regarding the PCU shut off CB as I don’t find that in my -1. There is a generic warning about resetting CBs more than once, which may be what you are referring to.

As for the Q3 for a student demo, there could have been a lot of reasons for that, some with no connection to actual aircraft control. Don’t know what they call SACR 60-4 now but something as innocuous as an inadequate briefing or debrief may have been involved. I remember when the KC10 blew up on the ramp at Barksdale and all the flying records of the crew that had last flown the airplane were collected for the SIB. Just part of their procedures.

edit on 2211112013 by ROFCIBC because: minor formatting error

I agree with you it doesn't make much sense when you put it like that. I was simply paraphrasing what the SIB said. So maybe they have something new since you and myself have left the tanker. I guess we will see soon.

"I agree with you it doesn't make much sense when you put it like that. I was simply paraphrasing what the SIB said. So maybe they have something new since you and myself have left the tanker. I guess we will see soon."

I'm going to do some reaching out to some contacts in the current KC135 force and see if the PCU shutoff, Q inlet, yaw damper systems are the same. I didn't fly the R model but with the increased thrust there might have been changes made to the rudder system to handle a larger asymmetrical thrust event.

I might point out that when the 135 had the powered rudder system added and went from the "short tail" to the "tall tail" the manual system was actually less effective. This had to do with removing one of the aerodynamic balance bays to install the PCU. Digging way back to my old IP days, I seem to remember it took 180 pounds of rudder force to maintain a straight track in the event of an engine out go around. I do remember demonstrating, and having students do manual rudder go arounds just to impress on them the importance of staying above Vimca. I wish I had the performance manual as I seem to remember Vimca in the manual mode could be really high, above some of the max flap extension speeds.

Nothing like a trip down memory lane. Can't believe it's been nearly 45 years since I first flew the 135.

Hi Boomer135,

I was part of the first search and rescue team that was tasked with Shell 77's crash-site cleanup and recovery. I just read the AIB report, in its entirety, today. It's been a long time since this happened but it still keeps me up at night. I still have nightmares regarding the images of the victims and feelings of deep remorse regarding the event. I also have bouts of disturbing memories involving being assigned to dig for remains where the cockpit impacted. Here, we found various remnants of the victims and personal effects as well. Another uncomfortable moment for me, that I can't seem to forget, was when we were searching for the boom operator.

They placed us into a UH-60 and transported us to conduct our sweep by the tail section of the crash site. I don't know why but in my mind, I just hoped that we could find him and that he would be alive. I knew that it wouldn't be possible but I still had hope. I found a fire extinguisher on our sweep. I didn't think anything of it until the NCOIC came to document it. The pin was pulled, he said that someone must have pulled it in an attempt to save the situation. I've been thinking for all of these years that someone pulled the pin and was trying their best to remedy a hopeless scenario. After reading the report, I'm not sure if this would be something that would have occurred or if the pin was caught on something and removed by its impact.

I recall the level of frustration that I felt toward the Kyrgyz military. On our sweep, we had Kyrgyz officers in-tow to babysit us. They had no respect for the crash site. They climbed onto the separated wings and other debris as if it were a toy to play on. They did very little to make our recovery run smoothly. It seemed like they were going out of their way to make things more difficult for us. They set up a stupid, #ty desk, on the dirt farm road that we were using to transport our men as a sort of ram-shackle checkpoint. It was extremely unnecessary. At one point, they stopped us from advancing with supplies for about 30 minutes for "administrative" reasons. To them, we couldn't have a continuous flow of supplies and men on the same road at the same time. It was ridiculous. I was mad. I wanted to get our people home. I just didn't know why they couldn't understand that.

They were unprofessional and unmoved by our loss. On one of my sweeps, a Kyrgyz officer offered me a joint. I couldn't believe it and promptly declined. It was incredibly inappropriate... I felt intense mourning over the loss of these 3 heroes. I didn't know them, but I wanted to make sure that they got home. I went on every patrol that I could, not resting until the sun went down. I wanted so desperately to find the boom operator and know that he would be ok. Unfortunately, it wasn't on my patrol when they found him. I was told that he was in the mountains.

I don't remember how many days I was out there, it all kind of became a blur. I was 3 days into my deployment when it happened. I didn't know what had happened but when I heard that volunteers were needed for something serious, I didn't hesitate. I threw myself into it, ready to do whatever I needed to. We were dismissed from our duty to get some rest before heading out. I think it was around 11pm when we were required to leave all of our electronic devices with the POC or face UCMJ punishment if found with them.

We didn't really know what we were getting into until we arrived, crash site still smoldering, in the early morning hours. We arrived to armed Kyrgyz military, which immediately set a negative tone as they were quite aggressive. Another issue that we had was that we had a very difficult time locating the black box (which I was told is actually orange). There were rumors circulating that the Kyrgyz military, since they arrived before us, had located the box and was refusing to give it to us until they reviewed what was on it. I was later told that the "Grounds Maintenance" (the contracted company that cut the grass and de-weeded the base) located the black box after coaxing the Kyrgyz military. I don't know how much of this is true.

Another thing I remember was that our vehicles destroyed a makeshift bridge that was built by the farmer of the land, and we made him a very nice culvert/bridge and made sure that they were taken care of. I guess, it wasn't until recently that I had a traumatic event that reminded me of key details about this mission. It was triggered by the movie "Rampage." There is a scene where an Air Force plane is brought down and the camera captures the moment from within the plane. I couldn't help but think, "was this what they experienced?" "Is this what it was like?" Then the camera panned out to show the point of impact where the plane crashed and crumpled into a field, complete with smoldering carnage. This was too much. It was too real. Too accurate. This ignited such a severe response of the recollection of events that I had to leave the theater and couldn't drive home.

I don't really know why I decided to create an account and share this information. Perhaps it's something that I needed to share. Perhaps I hope this will give me some sort of closer about the matter. I was disappointed to discover that not very many people know about this incident. My shop, when I returned from the deployment, was unaware that anything had happened while I was there. So frustrating. I hope that the families impacted by this event are ok, I never knew or heard about it after I left.

I was curious if you were still going to post the remaining information since the AIB is now public. If you don't have it anymore, I understand, it's been awhile. I just thought that it would be worth asking since I was so closely involved with the incident. If you have any questions or concerns, please feel free to let me know. I look forward to hearing from you.

Very Respectfully,
T. Waldrep

a reply to: Waldrept
Hello Waldrept and welcome to ATS and the aircraft forum. Thank you for sharing that unique insight on the crash. Such a personal account of the horrors is something often forgotten in the public eye by those who must respond and clean up after air disasters.

Boomer135 has gone quite the last 2-3 years as I believe he may currently not be in a position to public comment or post online. This sometimes happens to members here as they move around various parts of the industry. He very possibly will see your post but cannot comment. I am not 100% sure but Zaphod58 may be in some form of contact with Boomer and could pass on your request. I'm sure if you were to PM him on here he will quickly tell you whether he can help out or not. I look forward to your contributions in the future.