AEW in the Royal Navy

Introduction
The AN-APS 20 & Skyraider
The Fairy Gannet
The Hawker P139B
The Falklands
Sea King AEW2
Sea King AEW7
Other Operators
FOAEW

Introduction

This is a short article on the history of Airborne Early Warning (AEW) in the Royal Navy. The idea of AEW is very simple; a radar placed in an aircraft has a greater detection range than Radar placed on the mast of a ship. Ship based Radars are limited in range by the curvature of the earth, low flying aircraft can escape detection, almost until it they are upon its target, leaving the ship little or no time to react to the threat.

Early attempts to provide early warning of attacking low flying aircraft included having standing fighter aircraft patrols, but these could not be guaranteed to be in the right place at the right time, and placing radar equipped ships ‘up threat’, but these ships soon became targets themselves, as graphically demonstrated by HMS Sheffield during the 1982 Falklands War.

The AN-APS 20 & Skyraider

It was the US Navy that first introduced AEW at sea, fitting Avenger aircraft with the AN-APS 20 radar, in 1944. This allowed detection of a bomber sized aircraft out to ranges of 100 miles. Development continued and the AN-APS was next fitted into the Douglas Skyraider, this saw service with both the USN and the Royal Navy.

A Skyraider, from HMS Eagle (Eagle's aircraft had the tail code J) landing on, note the hook, taking one of the ships arrester wires.

Although the British Admiralty wrote a staff requirement in December 1943 advocating the use of AEW, it was not until 1951 when the first trials of the Skyraider were carried out by 778 Naval Air Squadron at RNAS Culdrose in Cornwall. Once the trails were complete, 778 NAS was recommissioned as the frontline 849 squadron in 1952. 849 was split into a HQ and a number of operational flights. The HQ flight trained aircrew, whilst the operation flights deployed aboard the fleets operational carriers.

The role of the Skyraiders was varied, they could search thousands of miles of ocean for surface contacts, the AN-APS could even detect the ’snort’ masts and periscopes of submarines. They could be used to direct attacks on surface shipping as well as provide early warning of enemy aircraft approaching the carrier group and vector fighters to intercept these hostile contacts.

The Skyraider gave sterling service, although it suffered some maintenance and spares problems, also its use of high octane fuel posed some safety  issues, thus during the mid 50’s thoughts turned to a replacement. The Fairy Gannet was chosen successor.

The Fairy Gannet

A version of the Gannet had been in service with the RN since 1955 in the ASW role, and this airframe was chosen to mount the venerable AN-APS 20 Radar. The prototype AEW Gannet flew in August 1958 and a total 44 AEW Gannets were built, again serving in the front line with 849 NAS, from February 1960.

The Gannet was a rather unique aircraft, as it was powered by a 3875 horsepower Armstrong Siddeley Double Mamba engine, with its two contra-rotating propellers mounted in the nose of the aircraft

A Gannet landing on HMS Eagle. By the time this photo was taken (Late 60's - early 70's) Eagles deck code had changed from J to E

This aircraft remained in service until December 1978 when 849 B flight disbanded following the decommissioning of the RN’s last fixed wing carrier, HMS Ark Royal.

P139B

The Gannet was to have been replaced by the Hawker Siddeley (formerly Blackburn Aircraft, Brough) P139B during the early 1970’s. This aircraft, intended to operate from the cancelled CVA01 class of carriers, had two wing mounted turbo fan engines, giving it a similar appearance to the USN’s Lockheed Viking ASW aircraft. The P139B wings folded just outboard of the engines to allow stowage in the carriers hanger and had the tailplane mounted atop the fin.

This aircraft was to carry a totally new radar, a Frequency Modulated Interrupted Continuous Wave Radar, which had scanners mounted fore and aft. This aircraft was abandoned when the CVA01 was axed, although the Radar was kept in development, it forming the basis of the system intended for the  Nimrod AEW3, which was supposed to enter service with the RAF during the early 1980’s.

Photo Credits

Sky Raider : A concise History of the Fleet Air Arm, published by the FAAM circa 1969
Gannet & Sea King AEW, Squadron crests: Royal Navy website
P.139B : Project Cancelled, new edition, Jane's Publishing Company 1986