Blimp over the Border

In the mid-1990s trials were being undertaken at Boscombe Down in Wiltshire, England for a new type of airborne surveillance platform. In the days before Unmanned Aerial Systems (UAS) were common place in military aviation, it was thought that an airship could be used in Northern Ireland to provide surveillance over areas of the border to which the series of watchtowers were blind1Hayward.

In a series of work known as Project COVERTIBLE, the Ministry of Defence purchased a Skyship 600B airship, serial number 1215/01, for the Defence Test and Evaluation Organisation at Boscombe Down. Procured for approximately £2.6 million2Hansard. This may have been a total project cost as opposed to the cost of the airframe, the 59m long Skyship 600B was manufactured in England by Airship Industries (UK) Limited and was one of only 10 Skyship 600s to be built by the company. The trials were established to assess the feasibility of using lighter-than-air aircraft as surveillance platforms over Northern Ireland. They were to be operated by pilots and groundcrew of the Army Air Corps.

Interestingly G-SKSC was the first Skyship 600 manufactured and took to the skies with a maiden flight in March 19843airshipsonline.com. However to confuse matters, registration G-SKSC is also listed as being a modified Skyship 500; by fitting the larger 600 canopy to a 500 gondola they could increase the lift capacity. This variant was known as a Skyship 500(HL) for Heavy Lift, and is reported to have flown first in 1984 in Paris4airshipsonline.com.

RegistrationOperatorDeliveredStatus
G-SKSCAirship Industries (UK) Ltd10/08/83First registration
G-SKSCInterport Marine Agencies Ltd20/02/91Left fleet
G-SKSCWestinghouse Surveillance Systems Ltd21/07/93Left fleet
ZH762Defence Test and Evaluation Organisation03/12/93Left fleet
ZH762Private Owner1995Scrapped
Aircraft history of the Skyship 600 from planelogger.com. There is evidence of the aircraft continuing in service after 1995 under the same registration, eventually being sold in 19985Hansard.

The Skyship 600B variant was built with a larger envelope (B for bigger6Dirigible Magazine) of 7,000 cubic meters, resulting in a lifting capacity of over 7,000 kgs. Weighing in at almost 7,000 kgs the Skyship 600 was a large aircraft; it was 193.6 feet long, 49.9 feet in diameter, and had a theoretical top speed of 60 knots (70mph). However, controlling the airship was problematic for the inexperienced Army Air Corps (AAC) pilots and groundcrew. The majority of ground handling, including moving in and out of the hangar and manoeuvring around the airfield often had to be done by hand, using rails on the gondola and ropes from the nose of the aircraft.

The control surfaces to the rear of the aircraft are essential for control, but only operate effectively at airspeeds of over 20 knots. Below this they are less effective, and below 10 knots (such as when coming in to dock) they have no effect. It was ultimately this loss of control when approaching the mast for docking at the end of a flying day that caused irreparable damage.7Hansard On 9 May 1995 pilot error resulted in the airship making contact with the mast and rupturing the envelope beyond repair. This report in parliamentary questions also coincides with the registration details that say the Skyship 600 was sold to a private owner for scrapping in 1995, however there is evidence that the airship continued in service after the incident.

A line drawing of the Skyship 600 from airshipsonline.com

In reading the article in Dirigible Magazine written by an AAC groundcrewman trained to handle the Skyship, he refers to the envelope being replaced with the large B model. I’m not sure when this took place, but it may be that the initial procurement was of a Skyship 600 (possibly even a 500 soft skinned variant) and the upgrade was undertaken to increase the surveillance payload of the aircraft. If this was the case, the upgrade to 600B would likely have taken place after the incident in May 1995 when the envelope was damaged beyond repair.

Northern Ireland Trials

In order to test the operational effectiveness of the Skyship as an observation platform, the Army conducted Operation DECOUNT; a number of deployments and trials of the Skyship in Northern Ireland in 1995 and 1997.8It is likely that the second trials involved the larger 600B envelope It was believed the IRA knew of the tests,9Hayward but then again it was difficult not to spot the large airship sailing across the sky, and for the observant among us, it was sporting a military registration number – ZH762. The issues with an airship in Northern Ireland were apparent; it was weak in icy conditions and strong winds, and was vulnerable to small arms fire, or even worse anti-aircraft weapons which the IRA were known to be in their arsenal.

The Skyship at RAF Aldergrove with 5 Regiment Army Air Corps in 1995 © AAC, image reproduced from Army Aviation in Ulster

An image (above) from Army Aviation in Ulster which is credited to 5 Regiment Army Air Corps. The picture shows the Skyship (identified as a model 500 which was a soft skinned variant) and states the manufacturer as Westinghouse, but I believe they undertook a surveillance refit of the aircraft for the MOD as opposed to full manufacturing. While they did have manufacture Skyships under licence, all the registration documents I have seen assign manufacture, or at least first registration, to Airship Industries (UK) Ltd. None of the records I have seen suggest the aircraft was exported to the USA, but AAC records may contain this information. The replacement of the envelope to a 600B version may explain the confusion between being a Skyship 500 and 600B.

A parliamentary answer in 2002 stated “Airship ZH762 was sold in 1998 following completion of trials for which it was purchased.” Following the trials there were no further plans for the British military to undertake trials involving airships. Project CONVERTIBLE was over.

References

  • Airships are Different, an article in the Army Air Corps Magazine, author unknown. Reprinted in Dirigible Magazine by the Airship heritage Trust, Autumn 98 / Winter 99
  • Our military might be hampered by snow, letter, Prof Keith Hayward, Guardian newspaper (online), 11 December 2020
  • Hansard, HC Deb 24 November 1995, vol 267, cc346-7W
  • Hansard, Bound Volume Hansard, Written Answers, 6 Mar 2002, Column 321W
  • Army Aviation in Ulster, Guy Warner and Alex Boyd, Colourpoint Books, 2004
  • Website planelogger.com
  • Website airshipsonline.com