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Date: February 18, 2013
Subject: Dropped Control Loop Attachment Links
Product: All National Oilwell Varco Top Drives with the
exception of PS, IDS-350*, TDXand HPS Product Lines (*Service Loop
J ackets are standard with IDS-350)
AffectedAssemblies : Service Loop Kits (Multiple Part Nos.)
Objective: Advise Customers of Falling Object Incidents,
Reiterate InspectionRecommendations and Advise of Upgrade Kit Part
Nos.
Issue: In the original release of this Safety Alert in September
2002 a non-injuryincident was reported when a TDS Service Loop
Connecting Link, (P/N
117434) fell to the rig floor.
The Connecting Link as part of the Ring Assembly (P/N 117125)
and incombination with a Cable Tie provides the connection between
Fluid andElectrical Service Loops to prevent tangling or snagging
as the Top Drive travelsin the derrick (see Figure 1).
The root cause of the original incident was due to improper
peening of theConnection Link, shown in Figure 2. This was remedied
by replacing theConnection Link in the Ring Assembly with a Shackle
(P/N 30170691) whichincludes shackle, bolt, nut and cotter pin.
Subsequently in J anuary 2013NOV received two additional reports
of non-injuryfalling object incidents involving this shackle in the
Ring Assembly. In theseincidents the cotter pin failed due to
service loop movement and the RingAssembly impacting over time,
which damaged the cotter pin and allowed thenut to back off.
Product Bulletin No.: TDS-02-11Rev D
Release Top Drive Dril ling System
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This impact occurs when the Cable Ties break and the Ring
Assemblies slidedown to the bottom of the Service Loops as shown in
Figure 3.
Solution: NOV recommends inspection of this arrangement for
missing components andany signs of wear or damage. If any of the
existing Ring Assembly hardware orthe Cable Ties have broken or
come loose it is recommended that they bereplaced immediately. The
NOV Service Manual recommends daily visualinspection of
hardware.
As an upgrade NOV has developed the Service Loop Jacket Kit
(P/NM614001693,(see Table 1)) which includes high strength fabric
jackets, shownin Figure 4, which replace the Ring Assembly and
Cable Tie arrangements usedin previous Service Loop Kits.
These jackets wrap around multiple service loops and are held in
place byheavy duty Velcro straps. The Service Loop J acket Kit has
proven reliabilitythrough field testing while also greatly reducing
the risk of dropped objectincidents.
Also included with these kits are installation instructions for
the jacketsand thekit drawing. The quantity of jackets per kit is
dependent on the number andlength of the service loops required for
the particular top drive. The part numberinformation is provided in
Table 1. Additional single jackets may be ordered byspecifying P/N
M614001693-600.
Failure to follow the recommendations and/or guidance in NOV
Product Bulletins mayresult in death, bodily injury or property
damage.
Operators should also refer to previous NOV Product Information
Bulletins and Safety Alerts athttp://www.nov.com/drilling for
additional information related to this issue and information
regarding safe operation, maintenance, and inspection
criteria.
Please contact your local National Oilwell Varco (NOV) Service
Center for price and availabilityof these kits or if there are any
questions regarding this alert.
http://www.nov.com/drillinghttp://www.nov.com/drilling
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Figure 1
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Figure 2
Figure 3
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Figure 4
Table 1Kit Part Number Information
