At the end of 2018 the Pakistan Navy put two refurbished Sea King helicopters into service as search and rescue helicopters. The 9.5 ton twin-engine Sea King helicopters are a 1950s design and the Indian Navy models were recently retired, most of them after 30-40 years of service. The British retired its Sea Kings starting in 2014 and the seven Pakistan purchased in 2017 were deemed the easiest to refurbish to a state where they would be good for another few thousand flight hours. To continue in service the refurbished Sea Kings will require a lot of maintenance and the greatest cost for these Sea Kings is the maintenance contract with a British firm that specializes in that sort of thing. It is believed only three of the seven will be restored to flying condition and the others will be used for spares.
The first of 344 British Sea Kings was produced in 1969 and the last in 1995. Most were manufactured in the 1970s and 80s. The British Sea King was a license-built version of the American S-61. Pakistan already has six Sea Kings but they are very old and very close to retirement or a major refurbishment. All these options are less expensive than buying new helicopters, which the Pakistani Navy cannot afford.
While there are lots of retired naval helicopters on the market there are far fewer small maritime patrol aircraft. Thus at the same time, Pakistan put its two Sea Kings into service it also put the first of two ATR 72 maritime patrol aircraft to work. Actually, these two are ATR-72s Pakistan already owned that were converted from transports to maritime patrol. The twin-engine ATR-72 has a cruising speed of 511 kilometers an hour. If it slows to 400 kilometers an hour the ATR-72 can patrol for six hours and stay in the air eight hours per sortie. The ATR 72 is a 22 ton transport that, when used for maritime patrol, can be armed with anti-ship missiles, lightweight anti-submarine torpedoes, depth charges, and even a pod-mounted machinegun. There can also be a sonobuoy launcher, a magnetic anomaly detector (MAD, to find large metal objects close to the surface), and a self-protection system (chaff, flares, jammers). Sensors carried can include a SAR (synthetic aperture radar) capable of tracking ships 220 kilometers away (when the aircraft is at 3,000 meters altitude). Basic equipment for the ATR-72 is usually search radar, day/night vidcams with zoom, sonobuoy dispenser, two anti-submarine torpedoes, MAD, and anti-missile defense plus electronic countermeasures. Despite all this anti-submarine gear, most of the time these aircraft will simply be searching for smugglers, poachers, or ships in distress. In these cases, the torpedoes and sonobuoys are not carried.