Assumption number one—and the sole assumption: “the helicopter is a valuable component of the ASW team.” If you disagree, stop here. Since it is axiomatic that destroyers are also “valuable components,” it follows that a marriage of helicopters and destroyers increases the capabilities of each.
Many technical problems will be examined further on, but there is a fundamental law—it takes its name from a Canadian vice admiral who, as Maritime Commander, has been its principal enforcer—which must be clearly understood before the marriage can be consummated. This is O’Brien’s Law: “A ship becomes an aircraft carrier, independent of numbers carried except when less than one.”
Stretching the marriage analogy to its most ridiculous extreme, tin-can sailors should be aware of what helicopter-brides require of aircraft carrier-husbands. Starting with the obvious, the list includes: landing space, hanger, workshops, and personnel accommodation.
That is just a start. The wants and needs of the bride include, but are not limited to: firefighting arrangements (probably more pumps), briefing and ready-rooms, meteorological facilities, precision approach radars, special landing aids, landing signals officers, Tacan, and other beacons, special aviation fuel tanks, pumps and dispensers, added radio communications, special night lighting, crash and rescue crews, and additional air controllers, magazines, and internal communications.
And that’s not all. If not thwarted at the outset, there are demands for: “chef tested” high-vitamin foods; specially air-conditioned spaces (for immersion suits); preposterous liberty status; super-quiet offices, and so on; and, most of all, constant praise.
At this point, the aviators are reading the next article and the sea-dogs retrenching yet deeper. But, do not despair, destroyermen; the marriage, if not easy, promises to be practical and rewarding with yields numerous and worthy.
How have the Canadians faced up to these problems? Let us talk ship’s organization first. The helicopter and its personnel, both aircrew and maintenance, belong to a shorebased parent squadron and come to the ship as a helicopter air detachment (HelAirDet) of that squadron. This ensures that the flight standards of the aircrew are monitored by a cognizant unit and that aircraft maintenance is supervised by a competent authority which also provides assurance that pertinent modifications are incorporated and that proper logs and records are kept.
The officer in charge of the HelAirDet, normally the senior lieutenant, is responsible to the captain of the ship for the combat efficiency and readiness of the detachment and also responsible to the captain as his advisor on the tactical and operational aspects of all aviation matters. The O-in-C remains responsible to the commanding officer of the parent shore squadron who requires that the detachment operate in accordance with authorized standard operating procedures both in flying and maintaining the helicopter. The O-in-C prepares performance evaluation reports (fitness reports) on all detachment personnel, and administers disciplinary control over them, but only in matters relating to their aviation activities. The captain directs the O-in-C to carry out tasks as he sees fit and administers discipline to all members of the detachment on nonaviation matters. He may comment on the performance evaluation reports of all the detachment officers. But, this is important, he writes the report on the O-in-C.
This arrangement is not without fault. What recourse has the O-in-C if the captain orders a mission flown in too dangerous or impossible conditions against the O-in-C-s advice? You will believe me, won’t you, when I say that this has not happened? Still, under such unthinkable conditions, an O-in-C could do worse than put his advice in writing!
A lesser fault is that the maintenance personnel are somewhat orphans in the ship and when in home port are occasionally called back to the parent squadron—perhaps even to nurse someone else’s sick birds. The worst of both worlds? Perhaps, but not dissimilar to VF or VS squadron practice.
At the moment, the Canadian HelAirDet is made up of about five pilots, two navigators (tactical coordinators), two observers (sensor-operators), and 14 aviation tradesmen. When at flying stations, approximately another dozen must be closed up from the ship’s company, these being firefighters, rescue divers, and so on. This presents a sizeable problem, as ideally these men should come from the non-watchkeepers, and it does place a heavy load on the day men divisions of the ship’s company—for example, supply. This manpower load is needed only during the actual launching and recovery, between which times these men may be stood down. On launch this is as soon as the aircraft clears the ship.
In practice, 20 minutes has proven to be ample time from “Hands to Flying Stations” to wheels off. Much of this 20 minutes is required in the starting and connection of extra ship’s pumps, checking communication equipment, and positioning the aircraft. To captains, being ever impatient, it appears to take overly long to spread the rotor blades and perform pre-takeoff checks. But, 20 minutes is ample and, if the aircraft is already positioned outside the hangar, 12 minutes is similarly reasonable. On recovery, 20 minutes again applies as a normal routine. In cases of emergency, men will react much faster. During the past year, in one ship, four real “Hands to Emergency Flying Stations” occurred and in all cases the ship was ready to recover in less than five minutes. In one event, a fire in the air, the deck was ready in two minutes and 45 seconds, several minutes before the smoking helicopter could get back. It would seem important that the ship’s company be told the degree of urgency.
How quickly one can launch depends on a number of factors. Whether the aircrew are dressed and the flight deck crew closed up are the main controlling factors. Turbines require really no warm-up, thus various conditions of readiness would seem to be more dependent on personnel than machinery.
Mission cycles are dictated by tactical situations, but exercise experience with the SH-3A Sea King favors a flight operation cycle of 12 hours, three 4-hour missions with two hot refuellings and crew changes. In this type of operation, the firefighters don’t get much rest, let alone do any departmental work, as they are continually dressing and undressing. There are parallels ashore.
Weather can present problems. Destroyer seamen, no strangers to wind and sea, now must become acquainted with pressure density, dew-point and spread, icing levels, adiabatic lapse rate, terminal forecasts, altimeter setting and myriads of other factors. The big ulcer-maker remains, as ever, fog. Nor can airborne pilots be relied on to warn of its formation; for some reason they often fail to fear or notice a deterioration of visibility. Perhaps they enjoy flying on instruments.
Fortunately, the kind of fog that forms suddenly doesn’t often happen with high wind and sea states. By day and if lacking close-in precision approach radar, the ship should steam at high speed to lay a long and visible wake. The helicopter can then be surveillance radar-vectored at very low altitude across this wake and by making a 90° turn, can follow the wake to arrive over the stern. High speed assists in another way for it reduces the helicopter’s relative speed of approach and thus adds to safety.
Although not completely reliable, stack heat will often dissipate fog briefly, so if at all possible, head directly into whatever wind there may be. This will keep the somewhat clearer area lying directly over your wake. Non-believers, look aft when next in fog. Also, when in low-flying fog, the ship’s track is often very visible from the air.
Naturally, one should never be so caught out. A twentieth or even a tenth of a mile visibility is below accepted aviation visibility minima anywhere, even with alternates available, but it has happened a time or two. A similar technique using carbon-arc signal projectors trained aft and possibly towing a battery powered strobe light on a fog float at long stay could be a reasonable emergency measure at night.
The Canadian DDHs are 366 feet long with a beam of 42 feet. These ships have twin fin stabilizers fitted at the turn of the bilge. This type of stabilizer becomes progressively more effective with increase of speed. The captain must select his launch/recovery course (Foxtrot Corpen) after considering the major factors over which he has no control, which are: wind speed and direction, height and direction of sea or swell, and sea room.
The factors over which he may have some control are: speed available from machinery, desired progress along mean line of advance (MLA), stabilizer effect, (a function of speed possible on course), and crosswind limits, which can be a function of helicopter load.
The object simply is to minimize ship’s movement, both in roll and in pitch. A computer can select the optimum course and speed in milli-seconds, but the programming is very slow; besides which only the seaman’s eye will detect and appreciate the cross-swell. In marginal conditions, the prudent captain will do a little empirical evaluating of courses before recovery; it makes for fewer crises and smarter deck operations. If, while in the process of doing this, the officer in tactical command (OTC) sends a “Station,” hoist the Black Pennant while making a significant puff of smoke. Do not rule out that the best course might be to run down-sea to reduce pitch and allow a more effective stabilizer speed. This is an unlikely circumstance, but a possibility.
At all times and in all weathers, the helicopter-destroyer must be maneuvered for flying in much the same way as does the more conventional carrier. The MLA is ever pressing and time spent on the reciprocal doubly delaying. It is in minimizing such wasted steaming that well-trained flightdeck crew, and a competent captain visibly demonstrate superiority.
Many readers are somewhat familiar with the Canadian DDH flightdeck landing system. In essence it consists of a winch, a cable, and a securing device. This cable is hauled up to the aircraft by a messenger line and then fixed into a probe protruding from the keel of the aircraft. Tension is applied and when conditions are correct, the helicopter is hauled down to the deck. The lead of the cable causes the probe to end up on deck within a four-foot box or “trap” irrespective of ship’s movement. Jaws in this trap snap closed around the probe and lock the helicopter to the ship. The helicopter is straightened and exactly centered on the deck by traversing the trap fore and aft, in the sequence of which operating, various ingenious geometric things happen to straighten the aircraft. After the blades are folded, the trap moves forward taking the machine into the hangar, if so desired.
In preparing the helicopter for launch, the two factors which affect ships maneuvering are the maximum cross- wind limit allowable for spreading the blades and the similar, but generally lesser, cross-wind limits for engaging (turning) the rotor head. Except during these short periods, the ship is free to maneuver as required, for the helicopter is firmly secured and can come to no harm. A hard wheel over by the helmsman may toss an ungainly flightdeck crew into the safety nets but the helicopter will still be secure.
While the cross-wind limits of most helicopters for spreading and engaging are generous, they may require a change of course off the MLA or a reduction of speed, but this is not likely except in strong winds. Once the rotor is engaged, there follows only the seemingly interminable (about one minute) period of pilot knob twiddling reportedly to test aircraft serviceability. In reality this is a union ritual of the trade. Finally a light on the Bridge will indicate “Ready to launch,” and it is then the time for a fast turn, steady-up on course, and push the “Launch” button. In fact, some push the button seconds before they are fully steady. This doesn’t matter too much in the launch phase, but is not recommended until well worked up. Never, ever, during recovery, please.
Recovery is rather the same, only backwards. Pilots prefer to recover at inopportune times, rarely exactly on schedule, and these requests are prone to coincide with breakfast, engineering casualties or sonar contacts. Aviators are thought to be photo-sensitive to the reds of the spectrum, the dim glow of “Warning Low Fuel” never fails to stimulate agitation.
Having already preselected your recovery Foxtrot Corpen, order the bird into “Delta” (waiting position), and send for a fresh cup of coffee. There will be lots of time, as helo-aviators invariably imagine a submarine contact just before breaking last dip. This syndrome is undoubtedly a reactive guilt complex and should be examined in a longer paper on Social Conscience.
With the helicopter in the “Delta,” turn to the Foxtrot Corpen and recover. Listening from the Bridge, the LSO chatter might be as follows: “Lower the messenger, raise the messenger, go. Left . . . more left . . . standby for hover tension . . . hover tension on . . . still more left . . . steady . . . steady . . . standby to land . . . back a bit . . . steady . . . land now, now, now!” Once hover tension has been applied the LSO waits for a comparatively steady deck to haul-down. In rough weather, this may mean a minute or so delay. In training, new pilots will sometimes miss the trap. This is extremely hard to understand, considering the guiding moments of the cable tension, but they do. The LSO merely releases the tension simultaneously calling with disgust “Wave off, out of trap,” whereupon the tyro resumes the hover, tension is reapplied and another landing attempted. Tailhook types, what say you? Better than the angled deck—and with no second circuit.
Once trapped by the probe, the pilot lowers a tail probe that engages in slots or bars on the flight deck and the LSO informs the Bridge “Full trap,” and the bird is securely tied down at two points. Now fully free to maneuver, the ship may be turned smartly back on course (this time the galley reports dinner gone) and with luck the wind conditions will be within limits for disengaging the rotors and folding the blades. If they be not so, make them so.
During a hot refueling, the most likely mishap is a bad fuel spill. For this reason, the aircraft should be held on deck by some device such as the trap, which will permit instantaneous take-off. Chains or tackles are a forbidden hazard. For the same reason, the air crew do not change around until hot refueling has been completed. That is also why there are five pilots. One is needed to act as LSO.
How long does all this take? In good conditions, the longest time will be the time taken in turning to the flying course. Night recoveries take longer, for as yet, pilots make a longer stern approach. In fact, recovery in light winds at night can be trying. It is often difficult to determine the wind direction accurately before altering to the apparent flying course. Another nighttime delay is the time it takes for the ship to accelerate (after a turn) to the desired speed required, as experience to date indicates that the pilots like to have rather more wind over the deck at night than in daylight.
In essence, unless the flight deck crew are well worked up and the captain alters course the instant the helicopter is secure, the ship can expect to be always astern of the main body, dashing back to station at high speed and thus going alongside the tanker to replenish every other day. Not only will everyone miss sleep, but the ship will be forced to operate in a manner which severely reduces her tactical efficiency.
So much for the major problems, there are a number of smaller ones that will create changes in normal ship’s routine. Most modern medium and heavy helicopters use gas turbine engines in one form or another, as their prime mover. Examine the vanes in the compressor and you will readily understand how a small “foreign object” can cause catastrophic damage. Paper matches, the bane of every executive officer, are probably less than a damaging mass, but the cardboard folder is not. The ship’s company must be educated into a new concept of upper deck tidiness, particularly during launch and recovery. No caps on the weather decks during this phase is standard and woebetide the signalman who lets fly a sheet of message pad when turned into wind. This is not an imagined hazard, it is real and although it has not to date been the cause of an engine failure in Canadian DDHs, it is a major worry to pilots. The greatest danger period is during launching, for during recovery, the ship will have been headed into wind for at least a minute or so before the engine intakes enter the area of vulnerability, by which time most “foreign objects” will have been blown away.
On the same topic, dumping of galley gash is to be discouraged when the helicopter is nearby. The engines may be able to swallow a paper match but a two-pound sea gull is definitely unpalatable. Moreover, bird strikes seriously damage rotor blades.
Another matter affecting ship’s routine is the refueling of the helicopter. While this calls for not a great deal more than ordinary precautions taken for similar shipboard evolutions, some aviation fuels require thorough pre-circulation within the pumping installations, and this will require that extra precautions be taken before the actual refueling event. Naturally, similar hazards exist while fueling ship, particularly underway. This article does not pretend to be a treatise on engineering procedures. Just remember that the higher distillates quickly anesthesize the sense of smell and the human nose is not a gas fume detector except for the first few whiffs.
Optimistically, a serious crash on deck will never occur, but no matter how small the individual probability, every gambler knows that the over-all chance increases to the power of the number of the events. While some may adjudge a crash as proper retribution for inept piloting, a fire arising therefrom will endanger the whole ship. Firefighting arrangements will differ with the classes of ship, but the ship’s company must ever keep the dangers in mind.
The captain’s initial responses in such an event are limited but vital. It will be his responsibility to alter course and speed so as to assist the firefighting and reduce the spread of flame. Inasmuch as conditions and configurations differ, there can be no preset guide. In some cases, correct action might be to stand on in course and speed, at least until the situation is evaluated, for once started, a turn the wrong way may take too long to correct. It is largely for this reason that the captain should be in a place where he can exercise immediate command during each and every launch and recovery. The executive officer also must look to his damage control organization to ensure that escape routes exist for personnel.
One more warning: spray. The Canadian version of the SH-3A is fitted with a shield or foreign object deflector in front of the engine intakes, but most helicopters are not so fitted. Icing aside, a dense cloud of spray hitting the helicopter just after lift off is the most dangerous situation, for it might flame-out an engine.
The trapped helicopter on deck is not subject to intake spray as the hangar will normally provide a good lee. Nor is it probable that spray will present a hazard when the relative wind is broad on one bow or the other. But beware of having the wind dead ahead when taking the occasional “green one” over the bow. Now the spray will fly aft at just the right height of around 65 feet to douse the departing helicopter. To date this has not happened, but precautions should not be overlooked.
As with any piece of shipboard equipment, better usage will accrue from detailed knowledge of the principles. For example, in a single rotor helicopter, torque from the main rotor is balanced by a counter torque from the tail rotor. Thus it can be appreciated that, in hovering over the deck, it can matter whether the relative wind is from port or starboard; in one case increasing and the other decreasing the power required to hover parallel to the ship. Which is best is dependent upon the direction of rotation of the main rotor of that particular helicopter. In heavy-load configuration this can be significant. Similarly, a reasonable understanding of ground effect, speed-versus-power-required curves and the specifics of fuel consumption will assist in taking the correct ship’s action more rapidly in such emergencies as would be precipitated by the loss of one engine in a Sea King.
Earlier, in describing the flight deck operations in Canadian DDHs, it may have been inferred that the LSO alone chose the correct moment to haul down the aircraft. While this is the normal event, to accomplish this, he must judge the ship’s movement, particularly in the pitching plane, and a view ahead is of assistance in predicting moments of relatively lesser motion. To this end, good voice communications between the captain and the LSO are sometimes useful, but it should be clearly understood that the captain’s word is only advisory. Indeed, even though the LSO is best situated to judge the relationship between the moving deck and the tethered helicopter, his order to “Land now” should not be mandatory. This must remain the pilot’s prerogative. Right up to the moment of trap, the pilot has the option to abort by releasing or “picking off” the hauldown cable. This is an extremely rare occurrence as the actual hauldown takes only about two seconds.
So much for the tricks of getting them on and off Launching and recovery are the evil necessities; what about the productive part? Small boys already know (in one way or another) a great deal about this and the finer points have no place in an unclassified article. However, there are some elementary points that may not be obvious and should bear on the captain’s or OTC’s tactical outlook.
In the case of surface ship ASW operations, the OTC now has a reconnaissance vehicle with both a locating and an attack capacity. While this is of itself not inconsiderable, what is often not appreciated is that the alert submariner will be aware that helicopters are around and thus will be forced to react defensively as he would in the cover of an ASW carrier. The helicopter may not find you the submarine, but he certainly reduces your vulnerability.
Again supported by VP aircraft, the helicopter can become the worth of another VP machine by taking over suspicious contacts and thus freeing the larger aircraft to continue its search. These are but two illustrations of potential hundreds; the point being made is that the ASW helicopter is a tool with versatility proportional to the users’ imaginations. Too often, it is used merely as another sonar platform to extend a screen either in width or in depth. Perhaps this is the most profitable use in many circumstances, but careful thought can frequently suggest better ones in the game of outwitting the submariner. Think “submarine,” but also think “distant submarine.”
The foregoing situations pertain to independent ASW groups. When operating with an ASW carrier, the scene is altered quite drastically, more by command relationships than by tactical considerations.
Being comfortable and capacious vessels with command facilities, aircraft carriers attract Very Senior Officers. Because of this and because carrier staffs act as though they are the only people who know how to use aircraft, you tend to lose the control of your helicopter. This is a natural phenomenon and is readily explained in terms of command relationships, maximum co-ordination of resources and centralized combat control. Take note, the robbery is substantiated on different and more specious grounds called Air Traffic Control.
There is no known solution. Be resigned to fly the helicopter in accordance with a schedule prepared in the carrier. Remember nothing is completely an ill-wind, take every opportunity to have the aircraft refueled on board the carrier and occasionally it may be more convenient to have some minor maintenance performed over there. Properly briefed, a resourceful aircrew can easily find valuable spares that naturally are in short supply to destroyers.
One word of caution, keep a close watch on how and where the OTC is employing your machine. You can be 30 miles downwind when the OTC sends you to investigate a contact 40 miles the other way. In strong winds, the outcome is not difficult to forecast, and be assured it is you will be held responsible. Yes, the bird gets back, but not to you.
Destroyers ships’ companies are parochially possessive with their helicopter detachments. When the aircraft is serviceable and has been airborne a lot, it is the pride of the whole ship. The HelAirDet are the heroes of the mess decks, respected technicians whose advice and help is solicited to solve chronic problems with ship’s equipment. But, when the machine is down, it is the “Edsel,” and its detachment are “passengers.” This is partly owing to the novelty of having aircraft in small ships and lack of knowledge of aviation maintenance techniques. The chief engineer, having worked with turbines all his life, does not understand why the airmen cannot resist pulling theirs apart so frequently. After a few months together, understanding begins to evolve and, more importantly, mutual appreciation and even assistance begins to develop.
This discussion has illustrated the subject against a background of ASW operations. The destroyer/helicopter marriage is not so limited. Operations in the assault, counterinsurgency, mine clearance, bombardment, and hosts of other roles come easily to mind. As with any weapons system, installation is costly, and efficiency takes time to develop. Operating a helicopter from a destroyer is not a gimmick, not something that can be used on odd occasions to supplant other shortcomings. It is a magnificently mobile addition which can be used to great effect in making the destroyer, more than ever, the workhorse of the fleet.
There is a rank due to the United States among nations which will be withheld, if not absolutely lost, by the reputation of weakness. If we desire to avoid insult, we must be able to repel it; if we desire to secure peace, one of the most powerful instruments of our rising prosperity, it must be known that we are at all times ready for war.
—George Washington, 1793