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Bin Laden Mission: More Wild Helicopter Tales

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Curiosity unsatisfied is like the itch that can't be scratched, which is how I feel in sorting through reports on the spec ops helicopter crash during the May 2011 raid that took out Osama bin Laden. I wrote about it in this blog a few months ago.

I keep seeing accounts of this event and although they agree on one basic fact—a helicopter definitely crashed—they certainly don't agree on why or what exactly happened. I've read three books on the topic: Mark Owen's controversial No Easy Day: The Autobiography of a Navy SEAL, Man Hunt by Peter Bergen and SEAL Target Geronimo by Chuck Pfarrer. Owen was a member of SEAL Team Six, the unit that carried out the raid, and was actually aboard the helicopter when it crashed. Pfarrer is a former member of SEAL Team Six and is now an author and screenwriter. He had no involvement with the operation.

In his book and a subsequent television interview with 60 Minutes, Owen said the original tactical plan was to "fly to the X" and fast rope assaulters to both the top of the bin Laden house and the compound ground floor simultaneously. He was in the ground insertion team, but as the helicopter approached hover and the team prepared to rope down, the aircraft became unstable, seemed to lose yaw control and touched down hard in the middle of the walled compound with everyone still aboard. It came to rest with its tail boom propped up on the wall and the tail rotor just outside the wall's perimeter.

No one was injured, so the SEALS disembarked, adjusted and carried on with the mission. But they made one change on the fly. After the crash, the second helo that was supposed to insert a team on the roof diverted and roped the team down from the outside of the compound or landed. It's not clear which. They then gained access through the compound's high walls with breaching charges, according to Owen's account.

Did the Black Hawk suffer a tail strike on the wall or some other damage, thus precipitating the crash? Bergen, who may have used sources close to Owen—or certainly sources different than Pfarrer's--seems to think that, as some have speculated, the helo got into vortex ring state—settling with power—and simply lost vertical control. "The biggest problem was not correctly matching the wall that surrounded the compound in the life-size mock-ups they had used for rehearsals," Bergen writes. "The solid walls of the actual compound had caused turbulent aerodynamics for the first Black Hawk when it hovered to drop the SEALS into the courtyard and had necessitated the hard landing." This squares with Owen's account generally, if not in detail.

But in his book, Pfarrer is having none of this. He claims to have talked directly to sources involved in the raid who told him the team did insert from the roof, as planned, and found and killed bin Laden within 90 seconds of insertion, not after a 15-minute assault from the ground floor, as Owen claims. Pfarrer says the roof team assaulted down through the building and took out other targets. Pfarrer also claims the crash occurred as the Black Hawk, which eventually landed on the roof, was repositioning to outside the wall to stage for the exfiltration. The aircraft lost control and crashed tail first into the courtyard, according his account. And it had nothing to do with settling with power, but a freak mechanical failure of dual electronic control systems that Pfarrer calls "green units."

From Army nomenclature I've found on the Black Hawk, I surmise that the U/MH-60 does have a dual channel flight control system—it's actually a stability augmentation system—that provides short term damping in all three flight axes. But because the two systems max out at 10 percent control authority, it's not clear to me if a dual failure would result in aircraft loss. Then again, the aircraft involved clearly were not plain-vanilla Black Hawks, having been tricked out with acoustic damping rotors and radar suppression features, not to mention other secret stuff we've never heard about. Pfarrer called them Stealth Hawks and claims that two even more super-secret helos called Ghost Hawks were in theatre but were kept on the ground when it was decided that providing fighter top cover for them would risk drawing too much attention from Pakistani radar and the Army simply wasn't willing to risk exposing the technology by losing it. It's possible that these aircraft are based loosely on the U/MH-60, but are in fact custom one-offs made just for such sensitive tactical work. It's just as possible that they don't exist, I suppose.

Why the difference in accounts? Pfarrer claims administration officials watched the operation in real time through an RQ-170 Sentinel drone link and knew the crash occurred on the exfil, not the insertion. So why did they—and Owen—hew to the story that the helicopter crashed on insertion? Pfarrer supports his claims with what he says are eyewitness accounts from Pakistani neighbors, corroborated by a Pakistani military report that claimed clear evidence of the assault having been carried out from the top down. In explaining how the widely photographed almost intact tail rotor section came to rest against an outer wall, Pfarrer said it was blown out of the compound when the SEALS blew up the crashed helicopter. I'm not sure I buy that. In this photo, that pipe looking thing snaking over the wall is the rotor driveshaft. Seems hard to believe it would repose like that if it had arced over the wall. Pfarrer doesn't offer a motive for these disparate accounts, merely claims that his version of the event doesn't match either Owen's or the Pentagon's. Not that it matters much, other than being a curiosity, but one should never mistake any of this for an NTSB finding of cause.

Indeed, some of Pfarrer's aviation reporting struck me as a little suspect. He described the RQ-170 departure from Jalamabad thusly: "The delta-shaped object lumbered down the runway…and lifted off on a pair of afterburners framed by titanium thrust vectors." He described the Sentinel as climbing vertically and capable of supersonic flight. The RQ-170 is a dark project, but what reporting has surfaced on it suggests that it's a single-engine aircraft, which is in keeping with drone design of that size and type. It's believed to have a GE TF34 turbofan engine, with about 9200 pounds of thrust. Two engines in that range would give a 10,000 pound drone a two-to-one thrust- to-weight ratio, far greater than any modern fighter, including the F-22.

The RQ-170, by the way, is the type that the Iranians claimed to have captured; it looks like a mini B-2 bomber. Drones have been mostly about stealth and endurance, not speed or the maneuverability provided by thrust vectoring. Mach +1 and stealthy drone would seem to go together like oil and water and afterburners wouldn't be on the short list of low observables. But then not many of us know much about what goes on in the dark programs. The fact that Pfarrer is also a screenwriter gives me certain pause, too, since screenwriting and truth aren't exactly joined at the hip. While we're on that subject, later this week, a feature film about the bin Laden operation by Kathryn Bigelow called Zero Dark Thirty will go into limited release. It's likely that it will use the crash-on-insertion scenario, whether true or not.

So, having read all this material, I have no better sense of what really happened to the helo than when I started. Even in my wildest conspiratorial speculations, I can't construct a plausible reason why the Pentagon would misstate the real reason for the crash. Maybe there is no explanation, not for the crash, but for sticking with a story that isn't true.

If you gain a certain grim entertainment from reading accounts of the same event that are profoundly different, these books are worth the effort. One thing all three of them do with not a hint of inconsistency is to describe, in at least general terms, the staggering capability these special operations teams—and related intel agencies--have developed during the past decade, not the least of which is super-secret helicopters that sound like distant waterfalls in the night.

Comments (24)

As they teach you in psych 101, three people seeing the same car crash can give honest yet wildly differing accounts. For me the highlight of the episode was the confirmation of the existence of these choppers after years of semi-credible reports.

It sounds like there is a bit of misdirection going on regarding the UAV story. They should stick to moonlight, swamp gas and weather balloons.

Posted by: John Hogan | December 9, 2012 9:50 AM    Report this comment

Never knew a screenwriter who let facts -- or reality -- get in the way of a good story line.

Posted by: John Wilson | December 9, 2012 11:07 PM    Report this comment

It reminds me of the British army's (unofficial) judgement of the RAF's stealth bombers.... "They are so stealthy that the enemy does not even realise it has been bombed...." But still, where would the US special forces be without a helicopter drama? (the idea of actually going in on foot or by motor car is impossible to the US mind.) At least this time the job was completed.

Posted by: Brian McCulloch | December 10, 2012 7:03 AM    Report this comment

Oh, the web we weave when first we practice to deceive, quoth Shakespeare all those years ago.

Conflicting details and stories from an improbable government story with heavy political implications?

Say it ain't so....

Posted by: Richard Sinnott | December 10, 2012 8:16 AM    Report this comment

"I can't construct a plausible reason why the Pentagon would misstate the real reason for the crash. Maybe there is no explanation, not for the crash, but for sticking with a story that isn't true. "

Maybe once the White House had fabricated a version of the story to make Obama look like the primary hero of the day, including made-up details to add "realism," no one at the DoD dared contradict them. Didn't the RS-71 Blackbird become the SR-71 because LBJ screwed it up and no one had the gumption to tell the boss he was wrong?

Posted by: Stephen Leonard | December 10, 2012 10:12 AM    Report this comment

What I get from the picture: The "Pipe looking thing" is the Tail Rotor driveshaft. Tail rotor drive shaft is bolted together in sections that are connected by "Hangar Bearings" and "Flex Couplings". When the tail boom broke the T/R driveshaft sections flexed enough to remain connected. Possibly, because the power train was not rotating at the time. D Newman (Comm. R/W 15,000 hrs)

Posted by: Davis Newman | December 10, 2012 1:59 PM    Report this comment

Here’s a twist from a 3rd-hand source (non-pilot?) using Pentagon sources.

P.259 of Top Secret America describes LZ activities thus: “The plan called for one helicopter to land in an animal pen inside the compound and another elsewhere in the yard. One assault force would enter the main building from a first-floor door, while the other would be set down on the roof and enter the third floor, where analysts believed bin Laden was waiting.”

Posted by: Wash Phillips | December 10, 2012 2:13 PM    Report this comment

P260: “On the flight, the stealth helicopters went undetected. But one encountered mechanical problems due to the unexpected heat as it tried to land in the animal pen. To avoid rolling, which causes most serious injuries, the pilot dug his nose down into the earth. The SEALS jumped out, along with Cairo, the Belgian Malinois shepherd whose job was to sniff out bodies—dead or alive—that might be in the building.”

Not read either book you cited, Paul, so this is the first I heard of an animal pen or the dog. If so, were animals present when they set down?

Posted by: Wash Phillips | December 10, 2012 2:14 PM    Report this comment

Davis, I agree with that assessment. But what struck me as odd and not consistent with Pfarrer's claim, is that it looks to me like the rest of the helicopter must have been on the other side of the wall and obliterated by the demo charges. The tail rotor section just dropped down, still attached to the drive shaft.

Pfarrer argues that the entire tail rotor section was blown from inside the wall and landed as you see it in the photo. That just seems less likely to me, albeit possible, I guess.

Is the dual "green unit" failure claim credible to you?

Steve, I don't see how either version makes Obama look more or less heroic. Or would be more or less embarrassing to the military. (Neither is embarrassing; this was a masterful mission.) Also, Owen wrote his book after Pfrarrer and said he did it to set the record straight.

But he doesn't say what part of the record isn't straight. Was it Pfarrer's fabrications or the administration's? Lots of heat, no light.

Posted by: Paul Bertorelli | December 10, 2012 2:21 PM    Report this comment

Wash, there's another inconsistency between the two versions. Pfarrer has the dog's name as Karo, Owen and Bergen have it as Cairo.

Owen, I believe, put Cairo and his handler in the helo that didn't crash. After aborting the roof insertion, they landed outside the walled compound and were tasked with setting up a perimeter, says Owen. They had about two dozen guys total so they had a pretty good perimeter force, plus a quick reaction force coming in on a Chinook. One of the books, I can't remember which, described Cairo is detailed to perimeter security and to chase "squirters"--targets who run away.

"mechanical problems due to the unexpected heat as it tried to land in the animal pen"

That sort of squares with the settling with power theory, although it's an aerodynamic not a mechanical issue.

Posted by: Paul Bertorelli | December 10, 2012 2:39 PM    Report this comment

Good job at journalism Paul, asking questions and pointing out internal contradictions and inconsistencies.

I have always wondered if the sea burial of Osama was out in the Gulf Of Tonkin. It would be appropriate.

Posted by: Richard Sinnott | December 10, 2012 2:48 PM    Report this comment

Paul, As to the tail boom, I see two possibilities, One, the aircraft landed in the compound, was damaged and the tail boom was blown over the wall by the demolition charges with a portion of the driveshaft attached, possible. Two, the tail boom struck the wall, as it came down, more likely. I am not a Blackhawk pilot, but don’t see a SAS failure causing the accident. SAS is to reduce the pilots workload, they should have still had full control of the aircraft and it would not affect power available to hover. Average temperature for Abbottabad in April is 54 – 73 (deg f), its only 4130’ agl. It should have been well within the aircraft’s capabilities. But, I’m sure someone has a UAV video that would answer most of our questions.

Posted by: Davis Newman | December 10, 2012 5:16 PM    Report this comment

Almost every pilot that smashes a helicopter tries to blame VRS as an excuse. To enter Vortex Ring State, it requires a descent rate greater than the helicopters down wash. This would be about 3000 to 4000 fpm decent rate for a Blackhawk. No helicopter pilot would descend at this rate at night or near the ground. It was not VRS.

Posted by: Bill Berson | December 10, 2012 7:29 PM    Report this comment

The first time I looked at the photos of the tail remnants I was tempted to say that we left a fabrication behind just to stir up some controversy; you have to admit that the destruction of the rest of the helo inside the compound was quite complete. I fully understand the desire to know details. I also realize that our gov't's track record on skewing the truth, regardless of administration, breeds mistrust. However, as a former USAF pilot, I think there are still things the public has no need to know. As you say, it's on the UAV video and one day we will likely know, but "want" to know and "need" to know are two different things. If you want to stir the pot, let's talk about whether or not Bin Laden was buried at sea or is still sitting in a cell somewhere ...

Posted by: Ken Holston | December 11, 2012 2:47 PM    Report this comment

Paul, though I have not read your book references, I reviewed the original news reports, aerial views of the helicopter in the compound, and the tail photos. This led me to a helicopter performance assessment. Density altitude, Gross Weight, and the effects on engine and rotor performance during hover are the primary factors supporting Mark Owen’s observations. Weight and Balance: Using Wikipedia data of the HH-60G, Payload weight is: 6,000 lbs. If 10 troops at 300 lbs each with gear add 3,000 lbs, plus crew, plus fuel, plus aircraft modifications are applied, these aircraft are most likely at Max Gross weight. Performance: News reports suggested 90+ deg F at the compound that evening with temperatures higher at ground level. 35 deg C at 4,000 ft is +6,000 ft during the mission approach and landing.

Posted by: PHILIP POTTS | December 12, 2012 9:54 AM    Report this comment

Most likely, mission planning utilized all the capability of the aircraft, which minimized any extra performance margin. If the free air temperature climb as the aircraft approached the LZ, hover power available from the engines and rotor would have been reduced. Since the engine power available goes down as the rotor power required goes up with density altitude, rotor demand will exceed engine capability and the rotor RPM will droop. [This is like getting behind the power curve, fixed wing.] Since hover requires more power than forward flight, the descent rate increases and control power diminishes by the square root of RPM. Finally tail rotor thrust authority drops rapidly [by the square root of RPM] which acts like the loss of tail rotor effectiveness. The aerial photos show the aircraft just over the compound wall, suggesting the tail cone struck the wall and severed during the arrival. The tail rotor blades show no damage other than the one on the ground. [I conclude loss of rotor speed during approach to the wall, tail strike and fracture.]

Posted by: PHILIP POTTS | December 12, 2012 9:55 AM    Report this comment

Bill Berson is correct: It’s Not VRS, this is a technical buzz word for not knowing what really happened. My parting comment: when I hear a story that recounts unsubstantiated facts, imagined technical explanations, in theatrical accounting for self gratification; it bestows no honor to the extraordinary efforts that our troops perform in harms way, each day. I hope any profits from these books find its way for their benefit. I thank our troops, one and all.

Posted by: PHILIP POTTS | December 12, 2012 10:00 AM    Report this comment

To see a visual of the transition from power avaialble to power required: watch the You Tube video; Mt Hood Helicopter Crash

Posted by: PHILIP POTTS | December 12, 2012 10:23 AM    Report this comment

Actually, the temperature on the ground during the assault was given as 64 degrees. Fairly cool. So the denalt wasn't too high. Also, as for weight, they had flown 100 miles, which requires a fair amount of fuel.

Also, Owen's observation was of a normal approach, followed by some wobbling or sinking, then a sharp yaw departure or turn. I suppose that's what you'd expect with loss of tail rotor effectiveness from a strike.

The pilot was lauded--rightly--for burying the nose before the spin got worse. Owen also said the aircraft came to rest inside the compound with the tailboom on the wall supported at such an angle that the main rotors didn't strike the ground and remained intact.

Pfarrer claimed it crashed inside the wall and, as is typical for helicopters, beat itself to bits on the ground, flinging at least one main blade 100 meters away. Only thing is, one photo I saw shows the hub with the blades appearing relatively intact, just as Owen said. (They were in a bed of blown-up, melted debris from the demo charges.)

Posted by: Paul Bertorelli | December 12, 2012 10:44 AM    Report this comment

It would not be surprising that bits came off the main blades, tip caps, weights,etc. but still remained in tact. It is essential to dump the collective to minimize body rotation caused by rotor torque. My best assessment remains: Loss of rotor speed during approach to the wall, tail strike with fracture, and very firm landing. If there was a loss of tail drive during the arrival, I would have expected a report of major rotation of the aircraft body and a much more difficult & harder arrival.

Posted by: PHILIP POTTS | December 12, 2012 11:16 AM    Report this comment

Here's a link to [one of] the Mt. Hood videos: www.youtube.com/watch?v=IEbMJuyRnHc

Posted by: Rush Strong | December 12, 2012 12:03 PM    Report this comment

I'm going to veer off from the technical aspect of the crash here, but deal more with the information sources. First a disclaimer: I've only read Owen's book.

On one hand, you have two writers who claims to have collected their information from "sources" who have 1st hand knowledge of what happened that night. On the other hand, you have Owen who claims to have been there--and his credibility was helped when the Pentagon came out threatening to court marshal him. From a damage control perspective, one would expect the Pentagon to have downplayed "No Easy Day" not throw a public fit about it. At that point, I give the credit to Owen for being credible.

My own question is, and I know that this question sounds like a conspiracy theory because it really is, whether "No Easy Day" is the Pentagon's way of effectively throwing the public a bone because everyone is really curious how this whole operation was pulled off. Knowing people who have high-level government clearance, they just don't share what they know and don't know until they have been given explicit clearance to do so. Period, end of story, no questions asked. That, I would argue would need some looking into so we can get a better picture of how the tail rotor ended up where it did in my opinion.

Posted by: Keith Mendoza | December 12, 2012 2:39 PM    Report this comment

"Whether "No Easy Day" is the Pentagon's way of effectively throwing the public a bone because everyone is really curious how this whole operation was pulled off."

Interesting question. We do know that Owen's book post-dated Pfarrer's by a few months and that Owen said he wanted to "set the record straight." But he didn't say what part of the record wasn't straight. Was he reacting to Pfarrer's book or administration claims? He doesn't say.

As far as I know, no one in the SEAL community has publicly challenged either Pfarrer's or Owen's accounts. All of this is merely fodder for the curious, of course. But it is curious.

Posted by: Paul Bertorelli | December 12, 2012 3:28 PM    Report this comment

In reviewing the accounts of the helicopter approach one more time, one significant contributing factor that I did not mention; Dark Night, Zero Light, Down wash Brown out conditions that made a precision landing extremely difficult. During the final approach, the compound wall would clear the pilots view but still be an obsticle during the tail low descent. A very tricky, complex situational awareness condition. An impressive effort.

Posted by: PHILIP POTTS | December 13, 2012 1:56 PM    Report this comment

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