Government: Human Error Caused Gudauri Rollback

Georgian Minister of Economy and Sustainable Development Dimitry Kumsishvili held a press conference today to announce initial findings of an investigation into the rollback of a 2007 Doppelmayr quad chair at the Gudauri ski resort, which injured 11 people a week ago.  French firm Bureau Veritas confirmed the lift’s initial stop was caused by a power outage.  “After the chairlift was stopped, the operator had to introduce specific sequence of procedures and after implementation of the certain actions, the operator had to switch the chairlift on to the diesel generator power and bring the tourist to the safe site,” a translated press release reads.  “Unfortunately, according to the current conclusion, the operator made a mistake. The combination of the actions that he should have had carried out were not implemented in compliance with the relevant instructions – it was a human error.”

The report notes the chairlift had undergone an inspection in December and was in “perfect technical order.”  The operator on duty at the time has been fired and may face criminal charges at the conclusion of the investigation.  The Head of Gudauri Mountain Management and Deputy Director of the Mountain Resort Development Company have both resigned in the wake of the incident.  Georgia is in active talks to retrain employees from Gudauri and other ski areas, though staff had been to training courses at Doppelmayr headquarters in Austria in 2017 and Poma was on site offering training opportunities as recently as January.  The government says there are 15 total chairlifts in the country that are “in line with the world’s advanced standards.”  A statement from Doppelmayr linking to the release notes, “We hope that the injured persons are getting well soon. This remains the most important point at the moment.” According to Minister Kumsishvili, all of those injured have been released from hospitals and invited to return to ski next year for free.

13 thoughts on “Government: Human Error Caused Gudauri Rollback

  1. chip0 March 23, 2018 / 9:45 am

    I’m not a lift mechanic, but shouldn’t this lift have had an automatic mechanism to prevent rollback? I know the failure of such a mechanism was a factor in the King Pine rollback at Sugarloaf a few years ago.

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  2. rich rofrano March 23, 2018 / 12:58 pm

    I find it difficult to believe that the lift had no mechanical anti-rollback device.

    >

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    • V3 March 23, 2018 / 3:22 pm

      This lift does have a rollback/emergency brake the issue is in order to evacuate due to the power outage the lift the operator/mechanic had pumped off this brake, unfortunately he/she did this before a source of holding/driving torque had been applied to the bullwheel.

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  3. Brian March 23, 2018 / 1:44 pm

    Having worked as a lifty once upon a time. The most we could do was to reset the hydraulic brake accumilator by hand pumping it (older riblet and dopp fixed grips) on lifts that had it. Only the OIC (operator in charge) could do that.
    Diesel ops were handled by lift maint, and very experienced lifties only. Some of them (I think) had to be engaged/clutched up in the machine shack.

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      • Mike Turley March 26, 2018 / 8:22 pm

        The what we call operator was probably on their phone or asleep the whole time

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  4. Big Wally March 25, 2018 / 2:33 pm

    Yeah, the lowly lifty or mechanic is the cause and he should be criminally punished. How about the level of training or system design? AT least they didn’t blame it on teenagers swinging in the chairs.

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  5. Peter Landsman March 25, 2018 / 2:50 pm

    A post from the Skilifts.org Forums:

    “Typically on most North American Doppelmayrs the “Evac” mover needs two of the three brakes opened manually (Emergency or Service and Rollback). The Evac operator(s) then throttle up the Evac engine and push the lift through the brake. This action tells the operator that the Evac has the load and the Emergency or Service brake can be opened manually).

    A lot of the safeties are bypasses in this mode. We practice the Evac on all of our lifts monthly, mechanics and electricians.

    Europe could be doing it differently, we’ll soon find out.”

    http://www.skilifts.org/forum/index.php?showtopic=10958&view=findpost&p=115954

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    • Peter Pitcher April 3, 2018 / 11:44 am

      what happens if the aux dies, runs out of fuel etc? And what ski area is this that relies on the operator to instantly manually apply the brakes in this event?

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      • RT February 12, 2020 / 1:07 pm

        Peter P,

        If you thoroughly read the above post from Skilifts.org it explains everything pretty well.

        In reference to a Doppelmayr fixed grip lift which is what this is, I would like to contribute my experience and expand on that a little;

        Assuming normal electric operations mode, in the event of a power failure a “Low Voltage” fault will occur and the lifts low voltage control system will “tell” the brakes to close. All Doppelmayr’s I have worked on have a battery backup for the low voltage controls in event of power failure.

        If all brakes fail to close, the physical action of the bull wheel rolling back, if only for a few inches, will cause a “roll back” fault, which will be detected by a tachometer on the bull wheel or in the case of older Doppelmayr’s, from a friction pad mounted on a swing arm on top of the bull wheel which actuates a limit switch.
        (This 2007 modern Doppelmayr evidently had no mechanical rollback device within the gearbox or on the bull wheel, if so this event would not have occurred).

        The lift has now safely stopped.

        In order to evacuate the passengers from the line the lift must first be placed in an “Evacuation” mode. The procedure now involves starting and connecting a Diesel engine to the main drive shaft via a series of belts and a disc to disc interlock requiring the manual installation of bolts. In North America this procedure is not typically performed by seasonal operations staff.

        All brakes are still engaged, this includes the service brake located on the main high speed driveshaft (transfers power from the electric motor to the gearbox), and the Emergency brake/brakes on the drive bull wheel.

        The diesel evacuation drive is then started and throttled up gradually, the driver waits for visual confirmation of the service disc dragging though the service brake pads, it is now safe to slowly pump open the service brake, increasing throttle in accordance with load (think of doing a hill start in a stick shift, applying gas to prevent the car from rolling back as you slowly disengage the parking brake to allow forward travel).

        The accident investigation reads that the operator had to introduce a “specific sequence of procedures”, a sequence that I have roughly described. In summary, (as V3 put it), they manually opened the brakes before enough torque was applied to the the bullwheel. Evidently they did not have the experience, knowledge to flip back the red handles on the brake cabinet, which dumps all hydraulic pressure from each system and causes the brake to close.

        “Evacuation” mode is used exactly for that, evacuation only, almost all safeties are bypassed, the operation must be supervised as the brakes will not close if the engine stops for whatever reason. For example, an Emergency-stop will literally stop the Diesel engine but the brakes will not close as they have been manually locked open, a loaded lift will then roll back until the weight on each side of the line equalizes (or as in this case, enough friction is introduced by the rats nest of stacked up carriers at the base.)

        Fuel exhaustion? Typically, a well run resort will have fuel topped off as this engine is only used to evacuate the line or to test the unit. Any motor can die at any time for any reason, hence the need for the diesel operator to be at the controls at all times, ready to dump those brakes!

        At the large resort I worked at, we started every diesel on a weekly basis and physically hooked up every diesel and ran the lift in that mode on a monthly basis. Seasonal operations personnel were welcome to observe but not permitted to perform this type of operation.

        In this report it is not clear if stated “operator” was part of operations or maintenance but if they choose to convict, they better be able to prove that they trained him.

        I hope this answers a lot of questions, sorry that it’s 2 years late.

        RT

        Experience – 20 years in the ski world, Australia and US; lift operations, maintenance and construction, including Doppelmayr, Yan, Riblet, SLI. Been out for 9 years now but most of it’s still knocking around in my head.

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  6. Peter Pitcher April 1, 2018 / 12:38 pm

    There is something missing here: generally all lifts have a high speed rollback prevention device on the high speed side of the gearbox, this of course can be disengaged manually if the lift has to be reversed. Did this lift-gearbox not have one? On all the fixed grip chairlifts that I have seen, the service brake (high speed shaft brake) does not release until the lift is started and-or torque is proven. Is the correct operating procedure on this lift to manually release the service brake?

    Liked by 1 person

    • Rob Withey April 2, 2018 / 11:09 am

      Many new lifts don’t have high speed roll backs. In evacuation mode the operation is totally different to main drive operation and control of the brakes is with the operator. Hence competency is required.

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      • Peter Pitcher April 3, 2018 / 12:10 pm

        I would like to know what the evacuation procedure was on this lift and who wrote it. When the result of the “investigation” is operator error then the training of the operator could be the problem but if the design is to disable the brakes and rollback devices and “power through the remaining brake” before disabling it, then this is a design problem

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