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Managing the Hazards: Extreme Cold Weather Helicopter Detachment Operations
Managing the Hazards: Extreme Cold Weather Helicopter Detachment Operations
By Lt. Patrick “The HOFF” Fonda, USN
December 2022, Helicopter Maritime Strike Squadron 51 (HSM-51) Detachment 1 “Komainu” embarked aboard USS Rafael Peralta (DDG 115), a guided missile destroyer, home ported at Yokosuka Naval Base, for a routine deployment in the 7th Area of Responsibility. This underway proved exceptionally dynamic, even as the ship/air team routinely operated in the cold, snowy seas near Hokkaido, Japan. Temperatures would typically fall to as low as -15 degrees C. Winter operations in 7th Fleet are historically known to be accompanied with heavy seas and poor weather which test both the ship’s crew and the helicopter detachment. These operations require an emphasis on operating at a world class level with hazard identification and proper risk discussions as key components to successful operations. DDG 115 and HSM-51.1 reinforced existing “all weather operations” capabilities during these operations and identified several lessons learned that other ship/air teams can utilize in their planning and execution phases on future operations.
Predeployment Preparations
Prior to the underway, the Helicopter Aircraft Commanders (HACs) of HSM-51.1 identified unique risks that the detachment would face for the upcoming deployment and included these in discussions with ship leadership and during the required Initial Ship Aviation Team Training (ISATT) safety briefs. The brief included an in-depth discussion on the need for a team mentality between the ship and air detachment, one that was exemplified in the operational relationship between the ship’s Captain and Detachment Officer in Charge (OIC). Specific lessons learned from historical flight deck mishaps provided talking points to enforce an increased focus on wave hazard plots and ensuring proper channels were open to communicating hazards between the bridge watch team (BWT), Landing Safety Officer (LSO), Helicopter Control Tower (HCO), and the helicopter crews were established early. These discussions also ensured small details were accounted for such as the BWT using the wave hazard plotter for all flight quarters operations and relaying real-time hazards to the LSO and HCO which greatly mitigated the risk of seawater crashing onto the flight deck and causing potential loss of personnel or damage to aircraft. DDG 115 had not had a helicopter detachment onboard for over a year, which although normal for ships completing routine maintenance cycles, is still something that must be addressed during underway workups with proper planning and training, effective and focused leadership, and overall crew motivation and enthusiasm in order to meet the standard required for operations in this AOR. The enthusiasm of the ship’s leadership and crew was a crucial element that would ensure proper risk decisions were made during the upcoming deployment.
Flight Deck and Aircrew Gear
With a projected winter deployment, our Det leadership identified a major concern with the gear our aircrew and maintenance personnel would be wearing on the flight deck. We had to ensure they could safely operate while being exposed to the extreme cold and wet conditions associated with flight deck operations. We identified that the standard flight gear issued to pilots and aircrew, with the exception of aircrew drysuits, would not be adequate enough to protect pilots and helicopter aircrew from the extreme weather. We quickly inventoried all flight gear and ordered the below gear.
Pilots and Aircrewmen:
1. Green GORE-TEX pants and jacket
2. Green Fleece jacket liner
3. Green Fleece neck warmers
4. Cold weather GORE-TEX gloves
In the aircraft, when flying in sub zero degrees Celsius temperatures or above cold water, pilots and aircrew are instructed to fly with standard issue dry suits; however, aircraft maintainers are not at all accustomed to cold weather. HSM-51 does a good job issuing all maintenance department Sailors blue cold weather jackets, rain gear, thermal underwear and gloves, but these would not be enough for extreme cold weather. Based on previous ship deployments, the HACs requested the use of Orange Stearns Challenger Anti-Exposure Worksuits from Deck Department to be used by all flight deck personnel. The ship had limited supplies of these suits, approximately 20, but covered the need to ensure maintenance and flight deck operations were conducted safely. These are highly recommended for any detachment projected to operate in extreme cold weather and should be discussed with ship leadership early in order to ensure availability for maintenance crews during the underway. If a ship is intended to operate for extended periods of time, the ship might not have enough for the squadron personnel and might have to be purchased or borrowed from another ship to supplement. Detachment personnel checked the anti-exposure suits out of the ship’s boatswain’s locker daily during shift turnovers. Sailors also wore Navy standard issue watchcaps when the ship wasn’t at flight quarters. Lastly, we highly recommend having the command purchase neck warmers as early as possible due to supply and acquisition lead times. At the time of our underway, neck warmers had a 3 month lead time so our detachment was unable to purchase these in time.
Maintenance Personnel:
1. Fleece base layers
2. Fleece neck warmer
3. Warm cold weather gloves
4. Orange Stearns Challenger Anti-Exposure Worksuits 1
Aircrew Training
Once the Det was on the ship, we conducted pilot and aircrew training on cold weather operations led by the HACs and our OIC who had previous cold weather flying experience flying rescues at an inland station SAR command. We based our training following NATOPS guidance and ensured all pilots and aircrew knew their operating restrictions and requirements and knew of potential risks associated with flying in snow and temperatures below freezing. We discussed the following:
1. Ice Buildup on the Flight Deck
2. High Sea States
3. Icing of Aircraft Systems and Equipment
4. Snow and Freezing Rain
Ship / Air Department Risk Decisions
Next came time to make risk decisions and apply time-critical ORM. Oftentimes, this involved both the aircrew and maintenance to come to a conclusion that would minimize time that not only the aircraft spent on the flight deck, but also personnel. The aircraft is susceptible to icing buildup in engine intakes, and oil lines expand and contract with the drastic change in temperatures, potentially leading to oil seal cracking and rupturing. Aboard a guided missile destroyer, the flight deck serves as the most hazardous workplace for aviation personnel even on days with excellent weather. Sitting less than 20 feet off the water, one wrong step could find an Aviation Machinist Mate in the water and potentially even lost at sea. Additionally, personnel on the flight deck are susceptible to
frostbite, fatigue, and hypothermia, posing a greater risk to the success of the air detachment. In order to mitigate the risk to both personnel and aircraft, the decision was made to carry out preflight checks in the hangar. Following the completion of preflight checks, the aircraft would be traversed to the flight deck and a rotor head and tail pylon check would be conducted prior to starting up the aircraft. Oftentimes, ice buildup would occur on the RAST control station—colloquially referred to as the “LSO Shack” on CRUDES deployers—which could potentially hinder critical visibility between the aircrew and the LSO. The solution? A mix of vinegar and warm water to prevent cracking the glass with drastic changes in temperature while preventing subsequent salt buildup and encrustation.
At night, pilots expertly and regularly land an MH-60R in waves over 10 feet, resulting in an incredibly dynamic nighttime shipboard landing environment. An additional hazard that required both in-depth and time-critical ORM was snow and freezing rain. Flying in icing conditions increases the risk of unusual vibrations in flight due to the buildup of ice on the main rotor blades, which is generally mitigated by the use of blade de-ice equipment. Ice buildup could lead to a multitude of issues, the most prevalent of which being that if drastic enough, the aircraft may be unable to establish autorotative RPM in the event of a dual engine failure. To mitigate this, the aircrew conducted blade-deice checks to ensure the main rotor and tail rotor deice systems on the MH-60R were working as advertised. The blade de-ice system on the MH-60R is designed to provide controlled electrical power to integral heating elements in the main and tail rotor blades, causing the ice bond layer to weaken, allowing symmetrical ice shedding. Further information on the blade de-ice system can be found in the MH-60R NATOPS, paragraph 2.22.3.2.
Hazards, Mitigations, and Recommendations
The following are additional hazards, associated mitigations, and future recommendations when operating in extreme weather operations that HSM-51.1 encountered in Northern Japan:
1. When the OAT reaches 5 deg. C or below with engines operating in visible moisture, the engine inlet guide vanes and the engine inlet are susceptible to icing. Ensure ENG ANTIICE Checks are done prior to launch, and ENG ANTI-ICE Switches shall be turned on when in OAT below 5 deg C in visible moisture.
2. On a Flight IIA DDG (as well as other CRUDES ships), “pad eyes” (tie-down points for the chains on the flight deck) are susceptible to icing when water is allowed to accumulate. This may result in the inability to secure the aircraft with tiedowns, or chains. Deviating from tie-down configurations could potentially lead to poor oversight as to where tie-downs are attached. HSM-51.1 mitigated this by ensuring pad-eyes were blown out at the end of every flight schedule.
3. When shutting down on potentially icy surfaces—i.e., the flight deck of a Flight IIA DDG—it is advisable to allow the rotor RPM to spool down smoothly, or coast down. Possible aircraft rotation could occur with rapid and excessive application of the rotor brake.
4. If the aircraft is to be spotted on the flight deck for an extended period of time, ensure scuppers on cockpit and cabin windows are opened. It may be counterintuitive, but this will allow sufficient air circulation to prevent frost buildup and reduce cracking of transparent areas due to differential contractions.
5. When flying in icing conditions and periods of reduced visibility, flight operations can be disorienting to not only the pilots but the entire flight deck team, bridge team, and tactical watchstanders. To mitigate this, it is recommended that the most senior aircraft commander embarked is on the bridge to facilitate proper risk decisions during time critical situations. At night, we recommend using a pair of standard issue NVGs to aid the bridge team in identifying worsening conditions at night and thus steer the ship away from conditions that would put flight operations in jeopardy. The remaining aircraft commander(s) and pilots should be in CIC and tower to provide real-time updates to all critical watch stations.
6. During operations in extreme weather and high sea states, keep the aircraft hangared to the max extent possible. We recommend conducting pre-flight checks with the aircraft hangared to minimize personnel exposure. Additionally, ensure heavy weather tiedown configuration is adhered to and RSD beams are open. This will prevent damage to the RAST probe due to prolonged fatigue stress.
7. It is important to accept risks when benefits outweigh the costs. For every executed fly day in extreme weather operations, there is a canceled fly day right around the corner. Prior to flight operations, it is important to analyze sea state, sea surface temperature, and forecast weather to determine if the benefit of extreme weather operations outweighs the cost.
In conclusion, HSM-51.1 flew over 100 hours in conditions rarely encountered by CRUDES-embarked HSM detachments, resulting in several lessons learned and recommendations to all future deployers in areas of extreme cold. We hope this article provides useful insight to the entire Rotary Wing Community.
NOTES: 1. Suits are Issued by the ship or purchased by the command. Website: https://www.fisheriessupply. com/stearns-stearns-challenger-anti-exposureworksuit/3000002911
