P-3A Orion

The P-3A Orion was not originally designed as an antisubmarine/patrol aircraft. It is a modification of the Lockheed Electra designed for commercial passenger operations. The application of a commercial aircraft to a military mission represents an acceptance of the Royal Canadian Air Force concept of using suitable commercial airframes in reconnaissance and patrol operations. The Orion, representing the most effective ASW compromise possible at this stage of the aircraft designer’s art, replaces the tired and now inadequate Neptune (P2V/P-2) which has served since 1947. Fleet patrol squadrons changing over to the Orion will enjoy the operational advantages of higher speed, greater pay loads, increased navigational accuracy, improved sensor equipment, better plotting and data-recording facilities, improved maintenance, better all-weather capability, more crew comfort, and more reliable tactical co-ordination.

Four Allison turboprop (T-56) engines ensure excellent performance in all phases of the Orion’s mission. Each engine develops 4,500 shaft horsepower, and the P-3A can climb, with combat loads, on two of its four engines. The aircraft’s fast cruise speeds reduce en route time by one-half, when compared with the Neptune. This time saved reduces submarine “escape time,” minimizes the size of the initial search area, and effectively increases endurance in the search area. The Orion’s low altitude endurance can be further extended as much as two to three hours by placing two of the four engines on stand-by (fully feathered) upon arrival in the search area. The aircraft’s stand-by engines can be returned to full-power operation in a matter of seconds, and the aircraft will accelerate to maximum speed from a two-engine configuration in less than three minutes.

The P-3A also performs well during low speed maneuvering. It will turn 180 degrees inside a radius of 600 yards at 180 knots while flying at its designed combat weight. The operational advantages of this aircraft over its predecessor accrue mostly from its turboprop engines. Their quiet and almost vibrationless operation—despite their impressive performance characteristics—provides a more stable platform for sensor devices and data- recording instruments.

A comparison of the Orion’s external dimensions with those of the Neptune footnote its greatly improved capacity for efficient ASW operations.

By comparison, the Orion has 225 per cent more cabin volume than the Neptune. This additional space, pressurized and air-conditioned, is a major factor in maintaining the crew at peak efficiency and permits efficient arrangement of operating stations without the crowding so familiar to SP-2H crews. The flight station accommodates pilot, co-pilot, and flight engineer in three-across seating. Instruments, emergency system controls, a tactical display console, and ordnance system controls are immediately accessible to flight station personnel. Of particular interest to aviators is the relative simplicity of engine management. Many of the instruments familiar to piston-engine pilots have been eliminated. Gone is the problem of co-ordinating manifold pressure and engine speed during flight maneuvers. Engine power in the Orion is controlled by a single lever which, in one movement, provides thrust as desired by the pilot. The Hamilton Standard, constant-speed propellers absorb additional power generated by increased fuel flow with instantaneous increases in the propeller blade angle.

The flight station is provided with complete tactical information in a display console which includes: a bearing-distance-heading indicator which provides true bearing and distance to the target and the true heading and track of the aircraft; a ground-track plotter which provides a continuous trace of the aircraft’s movements over the ground to assist in long-range navigation and target localization maneuvers; and an on-top-position indicator which provides the pilot with an indication of passage over operating sonobuoys.

The aircraft commander controls the release of sonobuoys and ordnance through an armament control panel which permits him to selectively release, jettison, or delegate control of armaments to the co-pilot or the tactical co-ordinator. Display lights on the armament control panel provide both pilot and tactical co-ordinator with a continuous inventory of ordnance remaining on board.

The spacious P-3A cabin accommodates a radio compartment and observer’s station directly aft of the pilot’s compartment, a tactical compartment with five side-by-side console stations, a sonobuoy-PDC stowage and dispensing station, an aft observer’s station and a crew rest area with bunks and a dinette- galley.

The tactical compartment is the Orion’s nerve center where detection systems are controlled and monitored. The aircraft is equipped with various sensor devices including radar, MAD, ECM, sonobuoy receivers, and the submarine trail detector. The plane’s navigator can pinpoint aircraft position with a variety of electronic systems. Localization maneuvers are further facilitated by the provision of inertial and doppler navigation equipment and the doppler air mass navigational computer.

The tactical compartment amidships is arranged to accommodate five operating stations, all connected by means of automatic data transmission and internal communications facilities. The first station aft of the forward observer compartment is manned by the radar/MAD/trail operator. The radar display provides surface search, IFF, weather and navigational data. The magnetic anomaly detector equipment is used to pinpoint and verify the location of suspected submarine targets. The trail detector provides evidence of snorkeling or surfaced submarines proceeding on diesel power.

Next to the radar station, the Julie /ECM operator controls ECM equipment and the sono recorder equipment also used to localize submerged submarine targets. A magnetic tape recorder is used at this station to record audio signals being received by the associated equipments.

In summary, the P-3 A Orion represents the most advanced airborne ASW system now operational in the Fleet. Specifically, it offers the shore-based air ASW team the following cumulative advantages:

• Improved aircraft availability—The Orion is designed to minimize the maintenance workload and, increase the flying hour performance of ASW squadrons. Most major system components are “packages” to simplify maintenance access, replacement, and unit repair. The systems that may require in-flight repair or servicing are either located in the cabin or are accessible from the cabin area.

• Applicability to future air ASW development—The Orion is designed to accommodate future equipment. The present configuration reserves 25 per cent of its useful volume for the eventual installation of future equipment. According to the Lockheed Corporation, the development of regenerative engines will, in the near future, “ . . . offer the prospect of phenomenal increases in the Orion’s range and endurance.” This kind of flexibility in design ensures the Orion a long and useful service life.

• Improved tactical performance and utility —The Orion’s relatively high speed, combined with its range and endurance, accrue a number of tactical advantages. The plane’s high cruising speed permits an unprecedented “quick reaction” to distant submarine contacts. Its reduced en route time effectively minimizes “time-late,” reduces the size of the initial search area (and submarine escape time) and extends time-on-station in the search area. The Orion can be quickly deployed to operating areas anywhere in the world from mainland bases.

• Additional mission capabilities—According to the manufacturer, the Orion could be easily modified to perform several additional missions. It could be used for minelaying, as an airborne command and control center, in emergencies as a troop-carrier, for weather reconnaissance, and as a conventional bomber against ground and shipping targets.

• Maximum crew efficiency—The Orion is a comfortable and spacious aircraft. Its vibrationless operation, reduced noise level, air-conditioning and pressurization, and interior arrangement all contribute to crew efficiency. The single most important factor in limiting the effectiveness of air search operations has always been “crew fatigue.” Consequently, the care taken in this design to promote crew comfort is not a luxury—it is essential. Commander Garrison is on the staff of Commander, Fleet Air Hawaii/Naval Air Bases 14th Naval District.