Siebold Shouted Yeehaw! Seconds Before Disaster Struck

Peter Siebold (Photo: Scaled Composites)
Peter Siebold (Photo: Scaled Composites)

Below is an excerpt from the cockpit recording of the SpaceShipTwo crash on Oct. 31, 2014. The transcript picks up as a controller gives the OK for the WhiteKnightTwo mother ship to release SpaceShipTwo. The spacecraft broke up 38 seconds later when its feather mechanism deployed prematurely during powered ascent. The powered portion of the flight lasted 11 seconds.

Descriptions of what is happening in the SpaceShipTwo cockpit and what pilot Pete Siebold and co-pilot Mike Alsbury are doing are in brackets [] and italics.

All times are given in UTC. The accident occurred at 10:07 a.m. PDT.


BASE 17:06:54.438
((scat two-one, glide trims good)) Green for release.

ALSBURY 17:06:55.41
Alright, stick?

SIEBOLD 17:06:57.27
Stick is forward.

SIEBOLD 17:06:57.37
[Places both hands on control stick and moves it to a forward position.]

ALSBURY 17:06:58.40
[Quickly moves left hand toward lower center console, then quickly moves left hand up to the LAUNCH CONTROL ARM switch.]

ALSBURY 17:06:59.98
Armed. Yellow light.

ALSBURY 17:07:00.40
[Removes left hand from LAUNCH CONTROL ARM switch, an amber colored arm pushbutton light below switch is illuminated.]

SS2-COCKPIT 17:07:01.23
[Pilot places head firmly against headrest and slightly readjusts his seated position. Remains with head positioned on headrest until vehicle breakup. Co-pilot’s head is slightly off headrest and moves toward instrument panel as he reaches for switches on panel. At no time during the boost portion does co-pilot’s head touch the headrest. There is slight noticeable vibration to the pilot’s helmet due to it being pushed against the structure of the seat and minimal vibration noticeable to the co-pilot’s helmet during boost portion of flight.]

ALSBURY 17:07:03.30
[Moves his left hand onto ROCKET MOTOR ARM AND FIRE panel and makes an upward motion in vicinity of a switch.]

ALSBURY 17:07:14.50
[Moves left hand near ROCKET MOTOR ARM AND FIRE panel.]

WK2 Co-PILOT 17:07:15.92
((five. four. three.)) Two. One. Release. Release. ((release.))

SS2 CREW MEMBER 17:07:19.01
Clean release.

SS2 COCKPIT 17:07:19.27
[There is a visible jolt to cockpit and occupants.]
[mechanical sound associated with the operation of the SS2/WK2 release mechanism.]

SIEBOLD 17:07:19.51

SS2 COCKPIT 17:07:20.00
[Shadow of WK2’s wing can be seen quickly crossing inside of cabin of SS2]

ALSBURY 17:07:20.13
[moves left hand toward ROCKET MOTOR ARM switch.]

ALSBURY 17:07:20.69

ALSBURY 17:07:20.87
[Makes quick motions with his left hand near ROCKET MOTOR ARM and FIRE switches.]

SIEBOLD 17:07:21.20
[Relaxes forward pressure on stick.]

ALSBURY 17:07:21.29

SS2 COCKPIT 17:07:22.73
[Both PFDs auto sequence to BOOST phase and graphically change.]

SIEBOLD 17:07:24.46
[strained voice] Good light.

ALSBURY 17:07:25.30
[Makes contact with left hand on left side of the control stick. Fingers and thumb of left hand appear to be around left horn of control stick.]

SIEBOLD 17:07:25.90
[Uses both hands on stick to make minor lateral movements to make left and right roll corrections.]

SIEBOLD 17:07:26.28
[strained voice] Yeehaw.

ALSBURY 17:07:26.80
[Begins moving left hand off of left horn of control stick. Begins left hand movement toward Feather Lock Handles.]

SS2 COCKPIT 17:07:26.83
[PFD speed display on both PFD auto switches from ADC to INS by displaying the KEAS gauge from a black to a greyish white background.]

ALSBURY 17:07:26.91
[strained voice] Point eight.

ALSBURY 17:07:27.37
[Places left hand on Feather Lock Handles.]

ALSBURY 17:07:27.47
[Moves Feather Lock Handles slightly right out of lock detent.]

ALSBURY 17:07:27.57
[LT and RT Feather Lock Handles appear wider than previously seen. Handles appear to slightly diverge.]

ALSBURY 17:07:27.90
[Co-pilot appears to be leaning forward and into a downward unlocking motion with his left arm and shoulder.]

SIEBOLD 17:07:27.99
[Pilot’s left thumb rapidly moved from right to left and back again in the immediate vicinity of the trim hat switch on the flight controls. The movement appeared consistent with a possible quick left lateral trim input.]

ALSBURY 17:07:28.10
[Left hand is briefly removed from Feather Lock Handles and LT and RT portions appear to converge.]

ALSBURY 17:07:28.27
[Left hand has shifted grip to LT side of LT and RT Feather Lock Handles.]

ALSBURY 17:07:28.39
[straining] Unlocking.

ALSBURY 17:07:28.40
[A slight right motion to move LT and RT Feather Lock Handles out of LOCK detents.]

ALSBURY 17:07:28.43
[A downward motion of Feather Lock Handles begins, handles appear to be slightly twisted with LT Feather Lock handle lower than RT Feather Lock handle.]

ALSBURY 17:07:28.60
[Feather Lock Handles are in mid transit.]

ALSBURY 17:07:28.90
[Feather Lock Handles appear to have reached UNLOCK position.]

ALSBURY 17:07:29.00
[Relaxes Left hand grip on Feather Lock Handles while still touching mechanism.]

SS2 COCKPIT 17:07:29.57
[FEATHER NOT LOCKED Light illuminates on backup panel.]

ALSBURY 17:07:30.07
[Moves left hand off of Feather Lock Handles.]

SS2 COCKPIT 17:07:30.67
[There is a slight but noticeable right roll indicated on ADI on both PFDs.]

SS2 COCKPIT 17:07:30.97
[FEATHER OK TO LOCK Light extinguishes, FEATHER NOT LOCKED Light remains illuminated.]

SS2 COCKPIT 17:07:31.40
[Both pilots’ bodies appear to begin to be pushed downward into their seats.]

SIEBOLD 17:07:31.42
[strained voice] Pitch up.

ALSBURY 17:07:31.76
[strained voice] Pitch up.

SIEBOLD 17:07:31.79
[Pilot’s left thumb rapidly moved to a position just above the trim hat switch on the flight controls and remains near the hat trim switch until the end of the recording. During this time, no forward, aft or lateral trim input movements were seen.]

SS2 COCKPIT 17:07:31.80
[Backup FEATHER POSITION INDICATOR Light appears to have moved slightly upward on scale. ADI begins showing a pitch up trend on both PFDs.]

ALSBURY 17:07:31.80
[Co-pilot’s head appears to move noticeably forward.]

SS2 COCKPIT 17:07:32.03
[Right roll indication on ADI on both PFDs appears to become more level.]

SIEBOLD & ALSBURY 17:07:32.26
[Sound of grunting]

ALSBURY 17:07:32.33
[Co-pilot’s head continues to move forward toward his lap. There is some movement of left hand off of left knee.]

SIEBOLD 17:07:32.37
[Pilot’s head begins to move off headrest and slightly forward.]

SS2 COCKPIT 17:07:32.47
[There is a noticeable vibration to the cockpit image.]

SS2 COCKPIT 17:07:32.80
[Both pilots’ torsos appear to be slumped forward with their harnesses restraining their bodies. pilots’ heads have been pushed forward toward control panel and almost into their laps.]

SS2 COCKPIT 17:07:32.80
[End of recording. End of Transcript]

  • Smokey_the_Bear

    Pilot error. it sucks, but is the most common cause of all crashes.
    At least the next spaceship2 won’t be able to be feathered while in the boost portion of the flight. That’s the one silver lining with all disasters, things become safer.

  • Kapitalist

    I just argued against pilot error here. But this doesn’t look good. I can understand that pilot errors occur on long boring routine flights. A test pilot in a spaceship should be alert. Maybe they have a poor organizational culture? “Yeehaw” as if he was a cowboy riding on a donkey.

  • Andrew Tubbiolo

    From the NTSB report …

    The copilot was experiencing high workload as a result of recalling
    tasks from memory while performing under time pressure and with
    vibration and loads that he had not recently experienced, which
    increased the opportunity for errors. – See more at: The copilot was experiencing high workload as a result of recalling
    tasks from memory while performing under time pressure and with
    vibration and loads that he had not recently experienced, which
    increased the opportunity for errors.

    Executing a check list in flight while tending to other issues leads the pilot to rush through a check list. I find myself doing it all the time when I have other issues to worry about as I’m doing my various check lists.

    My question after reading the NTSB summary and the cockpit recording and video narrative is did the pilots simulate the consequence of early deployment of the feather release? That’s a major sequence to pass through on the flight sequence and you would think that that would be a focus point in exploring the fault tree sequence during simulated missions. Waiting for that 1.4 Mach number should be a major milepost in the flight sequence that controlled the flow of events.

    The copilot was experiencing high workload as a result of recalling
    tasks from memory while performing under time pressure and with
    vibration and loads that he had not recently experienced, which
    increased the opportunity for errors. – See more at:

  • redneck

    “Yeehaw” as if he was a cowboy riding on a donkey.

    Right, we certainly can’t allow any enthusiasm for your work. Should be grounds for immediate dismissal and eviction from company property. Added benefit would be that a non-employee trespasser would have been on board and available to blame for everything. Might even be able to sue him for all the damages.

    Seriously, if you want it run by passionless robots, it should be a UAV, not a spaceship.

  • Stu

    I tend to agree, but equally, compare this to recordings of RAF pilot Andy Green driving Thrust SSC at Black Rock. I don’t recollect anything other than very controlled and dispassionate descriptions of what was going on. Calm and controlled is a state of mind, and “Yeehaw” probably doesn’t have a place. It is like when you activate the facial muscles to smile, you naturally become happy and your mental state changes to a more exuberant one. Seemingly small things do have consequences.

  • Kapitalist

    Maybe it was a planned PR gimmick? Would they release the communication, on a successful flight, for PR reasons? Relation to the accident is unclear anyway. A sign that he was relaxed, maybe.

  • Solartear

    What does Scaled/VG use for simulators in preparing testpilots for flying SpaceShipTwo?

    Before such an important and new test they should have the pilot and copilot running through simulations as accurate as possible to get the process right, even if the g-loads are not reproducible. I have not seen a cockpit mockup for simulations, but assumed there would be a good one somewhere, like the STS simulators.

  • Larry J

    There’s a saying that aviation regulations are written in blood. Regulations are based on the lessons learned from crashes. VG learned a lot from this crash. Going forward, the vehicle will be safer. Scaled Composites has always designed simple systems for their aircraft. I heard Burt Rutan describe this philosophy as “Plain Vanilla” at Oshkosh back in 1978. Simple systems cost less, are easier to manufacture, and can have fewer failure modes. However, simplicity can sometimes make human error harder to avoid. The feathering feature is intended to make reentry a carefree operation. However, failure of the feathering system will result in a catastrophic accident. Adding an Mach number based interlock system on the unfeathering mechanism can prevent the kind of human error that caused this accident but failure of the interlock mechanism can result in vehicle loss. This results in the need for a mechanical override for the interlock mechanism and more complexity, more weight, and more expense.

  • windbourne

    A donkey?
    More like a bronco or a bull.

  • windbourne

    You need to give your hatred a rest.
    The ship was bucking, and they were successfully riding it until the unlock.
    Yeehaw is more for the excitement. This was first time they were going up .

  • windbourne

    These 2 had ridden the craft already several times. It is understandable if the crew is excited about finally heading upwards.

  • Hug Doug

    There are ground simulators used for training. Also, the controls on the White Knight Two mother-ship are supposed to be identical (feathering mechanisms aside) to the controls of Space Ship Two, so flights of WK2 are sometimes used for training for flying SS2.

  • Hug Doug

    Highly unlikely. This reminds me of the whoops and cheers you occasionally got from the Apollo astronauts on their flights. It’s exuberance for the flight and doing something exciting – these are professional test pilots, but they will tell you there is a pure joy that comes from flying.

  • Charlie Sq

    At the end of the board the cause of the accident was determined to be Scaled and their lack of recognition of the pilot being a single point failure in the feather system. The pilot was a contributing factor, not the cause.

  • Charlie Sq

    Yeehaw was Pete’s signature. It allowed him to let Burt know his impression of the vehicle as he flew it. It is mentioned in Black Sky. Burt used to wait to hear it as confirmation that the aircraft was ‘good’

  • Larry J

    SIEBOLD 17:07:26.28 [strained voice] Yeehaw.

    Did he actually yell it or just say it? If he was yelling like Major “King” Kong riding the H-bomb at the end of Dr. Strangelove, that would be one thing. If he just said the word, it could just be a statement of being excited or a trademark expression.

  • Jacob Samorodin

    The crew were human beings. So one was delighted with what promised (and failed to be) an exhilarating ride and showed it.Not many people have experienced extreme high altitudes. Give them a break. And as human beings, they make mistakes, even tragic ones.
    Yeehaw means nothing. It is being used by the news reporter for some agenda of his or her.

  • Kirk

    I thought there was a better video, but there is some footage of the simulator starting at 07:18 in this press video. It is a non-motion simulator, and it was stressed in the NTSB hearing that the pilots have not worn flight gear during simulations.

  • twizell

    Interesting, it is Alsbury who calls out Mach 0.8

    ALSBURY 17:07:26.91 [strained voice] Point eight.

    And then

    ALSBURY 17:07:28.39 [straining] Unlocking.

    This to me suggests that he simply did not know that the feather should not be unlocked at that point.

    He was fully aware of the speed and clearly announced that he knew he was unlocking the feather mechanism.

    If he didn’t know but others in the company knew then this isn’t a human factors error at all but simply a lack of communication and procedures that meant the co-pilot was operating perfectly correctly at the level of knowledge he had and believed unlocking at Mach 0.8 was safe.