Monday, 2 January 2012

Static Discharge Cords



Static Discharge Cords

Only Labradors 302 and 303 were equipped with static discharge cords at the back of the aft pylon, each had four.  It appears that the static cords were affixed sometime after the aircraft were renumbered from the 400 series. Since other aircraft never received the cords it can be assumed that those that were so equipped were done so on a trial basis.  It is therefore probable the static cords did not meet expectations. Given the size, speed and materiel makeup of the tandem rotors, it was likely hoped that the cords would dissipate some if not all of the static electricity generated by the turning rotors. This of course is pure speculation on my part.

No indication of static discharge cords on 302 at this point.



And no indication of static discharge cords on 303 at the time of this photo.

Note the trial location of the CPI between two fuselage windows, and that 303 has only one search blister on the right side.





A SARCUP modified 303 now without the cords.
The tremendous amount of static caused some minor problems for those being hoisted. To dissipate the built up static charge persons being hoisted down wore a weighted length of light weight chain covered by rubber tubing that dangled a few inches below the persons feet so the chain would come in contact with the ground before the person. On one occasion, I was one of those hapless souls who neglected to attach the chain to the hook…when I contacted the ground the build up static charge reminded me why we used the chain. When on the ground, or a ship, waiting to be hoisted back into the helicopter we made a point of letting the hook touch the ground first so as not to get unceremoniously zapped.

By the time Labradors had been modified with tail mounted APUs, only aircraft 302 was left with the cords.  303 When modified for the APU received a completely new tail resulting in the elimination of the static cords, whereas 302 had received a new Voyageur style tail following its early incident.  As noted previously, 302 received the tail, but no APU…that is until all Labradors were fitted with the tail mounted APU.!


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