March 5, 2015, SAN DIEGO (NNS) – New procedures that will aid surface warfare officers and helicopter pilots while increasing safety during flight operations on destroyers have been successfully tested and recently rolled out to the fleet.
“Operator polar plots” (OPP) consist of a series of placard overlays that identify limits and safety considerations that take into account a ship’s speed and sea conditions in addition to pitch, roll and relative winds. Based on the height and direction of waves, a specific OPP is used by both the ship’s officer of the deck and the helicopter pilot to determine the best options for safely landing a helicopter on a ship’s flight deck.
Destroyers and their aviation detachment crews fleetwide have been trained on using the OPPs. As well, surface officers in training pipelines including the Basic Division Officer Course, Surface Warfare Officer School, and prospective CO/XO indoctrination are also being trained on their usage before heading to their new commands.
“This was a joint effort across several commands,” said Capt. Jack Olive, responsible for aviation operations aboard surface ships for Commander Naval Surface Force, U.S. Pacific Fleet. “Naval Sea Systems Command, Naval Air Systems Command, Naval Air Forces, Navy Safety Center and Naval Surface Forces worked together to address the safety concerns of landing helicopters on low freeboard flight decks, such as destroyers.”
A low freeboard flight deck is one that is close enough to the surface of the water such that a wave could wash over the flight deck, creating a hazardous situation for crew and equipment. Olive noted that Arleigh Burke-class destroyers have a flight deck approximately 13 feet above the waterline.
“Because the deck is so close to the waterline, conditions could exist that allow waves to more readily come over the deck,” Olive said.
He said such a condition was cited as a factor in a 2013 mishap aboard an Arleigh Burke-class destroyer where two aviators lost their lives and an MH-60S Seahawk helicopter was lost when a wave washed over the deck and swept the helicopter overboard.
“We are continuously reassessing our safety procedures,” said Capt. Curtis Shaub, aviation safety director for Naval Air Forces. “In this case, we specifically looked at how best to prevent this sort of mishap from occurring in the future. We have been working to mitigate the risks involved and to come up with a better, more comprehensive solution.”
OPPs are placards that officers of the deck use to plot the ship’s heading and speed, with overlays designed for certain sea states to determine limits for safe handling during flight operations. The direction of waves relative to the ship heading and ship speed are also marked on the placard. This plotted point will exist somewhere on the graph and if a given condition (denoted by different colors and crosshatch marks) indicate potentially risky or dangerous conditions, the ship can take actions, such as adjusting ship’s course and speed, to mitigate those conditions.
Ship speed is shown in five-knot increments on concentric circles from the center of a graph, with waves shown relative to the ship’s position. Red and yellow areas are speed-heading combinations to be avoided. Regions defined by dark lines with cross hatching reflect areas where launch and recovery roll and pitch limits may be exceeded.
“We conducted a preliminary exercise in September by giving the polar plots to six officers — three surface warfare officers and three pilots — with only a written explanation and no other guidance,” said Olive. “They were put in situations that required them to use polar plots to assess and manage the risk. The group successfully used the polar plots with ease and recommended integrating them into the fleet.”
Shaub said while no single procedure or process can fully prevent future mishaps, the goal of utilizing OPPs is, “to provide Sailors with risk mitigation tools which will help them to make more informed decisions.”
“Operations at sea and in aviation are complex and inherently dangerous,” he said. “Our sea-air teams are trained to look at everything we do from exercises to real-world operations through a lens of safety. Now that these OPPs have been integrated throughout the fleet, we’re better prepared for challenging sea conditions. We’ll be monitoring their effect and continually improving them based on what we learn.”