Underground Airfields: The DPRK

INTRODUCTION

During the Cold War, NATO and Warsaw Pact nations erected numerous hardened aircraft shelters (HASs) to protect their multi-million dollar combat aircraft during wartime. Over time, this practice spread throughout the world's conflict zones, with similar structures being found in many Middle Eastern and Asian nations. Some nations, however, took this practice one step further: they began building full underground facilities (UGFs) to store aircraft.

UGFs are commonly used in many nations to store and protect military hardware, but only a few nations have used them to protect their combat aircraft. These nations include the DPRK, China, and Taiwan in Asia, and Albania, the FRY, Sweden, and Switzerland in Europe. In this feature, the facilities used by the DPRK will be examined.

THE DPRK

Twenty major airfields in the DPRK feature significant UGFs for storing combat aircraft. In addition, two locations feature unique runway layouts incorporating UGFs, and seven airfields feature no UGF storage facilities. The locations of these facilities can be seen in the image below. The airbases incorporating UGFs are marked in red, those lacking UGFs are marked in blue/white, and those incorporating hardened airfields are marked in yellow.
UGF DESIGN

There are two basic UGF layouts employed by the DPRK to protect and house combat aircraft. These facilities are either positioned close to the main runway, facilitating ease of movement between the UGF and the operations area, or further afield, suggesting their use primarily for long-term storage. In addition, they are connected to their assigned facilities using two different taxiway styles. Some UGFs are connected by simple taxiways which wind their way through bulidings and terrain to reach the runways, while others appear to have a more interesting purpose, that of a backup launching strip for concealed assets. This information, combined with an analysis of the types stationed at each location, can give an indication as to the employment strategy or readiness level of aircraft contained within. Three airbases will be examined in detail to provide an overview of the DPRK's UGF design, layout, and potential use.

Sunchon AB

Sunchon AB is arguably the DPRK AF's most important installation. Situated approximately 40 kilometers northeast of Pyongyang, it is home to the most advanced combat aircraft in the DPRK. Sunchon AB is home to the DPRK's MiG-29 (FULCRUM) and Su-25 (FROGFOOT) fleets. The MiG-29 represents the DPRK's only true modern, 4th generation fighter aircraft. The Su-25 is likewise the only true survivable, modern ground attack aircraft in the DPRK. Sunchon's MiG-29 unit also makes up roughly half of the BVR-capable combat aircraft in the DPRK, with Pukchang's MiG-23 (FLOGGER) unit being the only other BVR shooters in the AF's inventory. Despite widely published claims to the contrary (including a thoroughly ludicrous Wikipedia article), whereby the MiG-29 fleet is believed to be based at a host of other locations, Sunchon is the only facility where the MiG-29 has been imaged inside of the DPRK.

An overview of Sunchon AB is provided in the image below, with significant facilities or features annotated:
Sunchon's UGF is situated in close proximity to the airfield itself. There are three main entrances, with two entrances likely leading to the storage area for operational aircraft. The third entrance may be for long-term storage of derelict or obsolete aircraft, or for entrance into a dedicated maintenance or GSE storage area. Sunchon's UGF is connected by a series of taxiways to the main apron area.

An overview of the UGF at Sunchon AB can be seen in the image below:
Sunchon AB has ramp space for roughly 34 combat aircraft, with HASs for four more aircraft. There is also an alert or arming/dearming pad at the north end of the runway which can easily park two aircraft. Open ramp space is therefore provided for at least 38 aircraft. 66 modern aircraft, discounting possible attrition since delivery, are based at Sunchon AB, indicating that at least half of them are stored in the UGF at any point in time. 36 Su-25s and 24 MiG-29s were delivered from the USSR, including 4 UB/UBK training versions of each type, as well as 6 MiG-29S (FULCRUM-C) SKD kits assembled in the DPRK. It was the MiG-29S that was used to intercept a USAF RC-135 in 2003.

Analysis of imagery of Sunchon AB provides insight into a number of factors. First, while between 19 and 29 Su-25s are visible depending on the date, only 5 to 9 MiG-29s are visible. This may indicate a much lower readiness level in the far more technologically complicated MiG-29 fleet. Second, it would appear that aircraft are moved from the UGF to the parking ramps for operations, before being re-stored. The image below depicts an open UGF, and an Su-25 being towed from the apron back to its underground hangar:
Furthermore, analyzing the layout of Sunchon AB in relation to the UGF illustrates an interesting feature. A 1350 meter taxiway extends from the UGF to a point beyond the main parking aprons. This taxiway may in fact be an auxiliary runway, allowing aircraft to be prepared for flight while concealed within the UGF and then launched with little or no warning for a strike against the ROK. While the MiG-29 would likely be employed to defend the skies above Pyongyang, the Su-25 is certainly a credible platform for use in this capacity given its relative survivability (compared to other available air to ground platforms in the inventory) and its high payload. Alternatively, this may facilitate the storage of armed, combat-ready MiG-29s in an alert status, protecting them from the elements while other airframes are removed for training flights as needed.

Sunan AB

Sunan AB, situated just north of Pyongyang, is the primary home to the DPRK AF's air transport assets. Assigned aircraft include the DPRK's Il-76 (CANDID) fleet. It also serves as the major international air terminal for the DPRK.

An overview of Sunan AB is provided in the image below, with significant facilities or features annotated:
There are no identified combat aircraft at Sunan AB, but the UGF can be used to illustrate a different layout than that of Sunchon AB. In the case of Sunan AB, the UGF is situated a much greater distance from the main operating area, likely indicating that aircraft stored therein are not operational or are being held in storage. Also, the UGF is not connected by a taxiway suitable for use as an auxiliary runway, reducing the chance that assets contained in the UGF are suitable for rapid deployment.

An overview of the UGF at Sunan AB can be seen in the image below:
Hwangju AB

Hwangju AB, approximately 40 kilometers south of Pyongyang, is home to a DPRK AF MiG-21 (FISHBED) unit.

An overview of Hwangju AB is provided in the image below, with significant facilities or features annotated:
Hwangju's overall layout is similar in many respects to that of Sunchon AB. Hwangju features three ramp areas and four HASs for housing its assigned aircraft. It also features a UGF complex for storing MiG-21s, which is connected to the main facility by an auxiliary runway similar to that found at Sunchon AB. The primary difference in the two facilities is the distance. Sunchon AB features a UGF in relatively close proximity to the main airfield, suggesting that combat aircraft may be stored there on a regular basis. Analysis of the available imagery would seem to validate this theory. In contrast, the UGF complex at Hwangju AB is much further removed from the main airbase. Imagery indicates that a consistent number of MiG-21s, around 20, is parked on the main ramp space of the airfield. This suggests that the UGF is not used for primary storage of aircraft, as it appears to be for Sunchon AB's MiG-29 fleet. This illustrates the relationship between UGF location and storage activity in the DPRK AF.

An overview of the UGF at Hwangju AB can be seen in the image below:
HAS Use

As operational fighter bases, both Sunchon AB and Hwangju AB possess four HASs in close proximity to the main runway. These facilities are likely employed for alert aircraft, enabling them to be protected to a degree from a preemptive strike. While aircraft parked on open ramp areas are soft targets, those contained in HASs would potentially be available for airbase defense or counterstrike sorties in cooperation with aircraft retained within the UGFs.

HARDENED RUNWAYS

Onchon airbase in the west and Kang Da Ri airfield in the east feature unique hardened facilities. These airbases incorporate large UGFs for storage, maintenance, and operations work, with runway surfaces exiting the UGFs in multiple directions. No information is available as to the purpose for, use of, or units assigned to these facilities. The most probable use for these unique airbases is as dispersal sites for combat aircraft. They represent very survivable hardened structures, and could potentially house a significant number of aircraft. The only drawback is that deploying a significant number of aircraft to each facility would be a potential identifiable indicator of forthcoming hostile action. To mask such activity, the DPRK would likely establish routine training deployments to each location.

An alternative use for the hardened airbases has nothing to do with aircraft and at this time represents pure speculation. Given that air activity at either location has never been publicly disclosed or identified in imagery, an interesting concept would be to employ the facilities as hardened SSM bases. The facilities resemble airfields in their layout, but a concrete SSM launch pad is little different from a runway surface. Ergo, the DPRK could stockpile SSMs in these facilities, using the "runways" as mass launching areas. In this scenario, transporting SSMs to the facilities would be far easier to mask than the deployment of combat aircraft. The facilities could represent logical storage and mating points for nuclear or chemical warheads, allowing them to remain protected prior to use. Furthermore, what better way to hide an SSM base than by designing it as an airfield? The only serious additional expense would be the additional concrete used to create a "runway" rather than a number of SSM launch pads. In this vein, given the security and survivability of these facilities, they could also represent launch points for UAVs or drone conversions of obsolete aircraft armed with nuclear warheads. At this point in time, however, the facilities are assumed to be exactly what they appear to be: hardened airfields.

Onchon AB

Onchon AB is unique in the DPRK as it possesses both a traditionally designed airfield and a separate hardened airbase facility. The airfield itself is home to a number of old, outdated combat aircraft including the MiG-19/J-6 (FARMER).

An overview of Onchon AB depicting its location relative to the hardened airbase can be seen in the image below:
The hardened airbase at Onchon consists of a single massive UGF with multiple entrances, and three runway surfaces. The facility was noted as being complete in January of 2004. The two primary runway surfaces lead directly into the massive UGF. A third surface useable as an auxiliary runway is connected to the main facility through a taxiway leading to one of the primary runways and to two secondary, secured UGF entrances. These secured entrances may lack the clearance for combat aircraft to use them to gain access to the UGF, but may provide entrance and exit points for GSE or other necessary equipment. A small exterior parking ramp is also provided, possibly for alert aircraft.

Details of the Onchon AB hardened airfield can be seen in the image below:
Kang Da Ri AB

As of 2007, Kang Da Ri AB was still under construction. It is a hardened airbase similar in concept to that found at Onchon. Kang Da Ri AB consists of a large UGF with two separate entrances leading directly to runway surfaces. There is a separate external runway surface, but unlike Onchon it does not lead directly to a UGF portal. Instead, it leads to one of the main runway surfaces via a taxiway still under construction in the latest imagery.

Details of the Kang Da Ri hardened airfield can be seen in the image below:
STRIKE OPTIONS

Employing UGFs to store aircraft does not necessarily mean they will remain viable combat assets. There are numerous options available for negating the impact of these facilities. While penetrating weapons may not be able to access the UGFs themselves from above, PGMs could be used in an attempt to destroy the access doors to the facilities, collapsing the entrances and sealing the aircraft inside for a period of time. Taxiways and auxiliary runways could also be cratered and seeded with bomblets from cluster munitions. The value of the UGFs therefore depends on the ability of DPRK personnel to clear and repair runway and taxiway surfaces and gain access to the facilities to allow the assets held within to be deployed.

CONCLUSION

The DPRK employs a number of UGFs throughout the nation to house various types of military equipment. The DPRK's Air Force is no exception, and the employment of UGFs will ensure that a portion of the air element remains viable after a first series of strikes by the ROK or USA.

SOURCES

-Satellite imagery provided courtesy of Google Earth

Site Analysis: The Ulan-Ude SAM Garrison

INTRODUCTION

The SAM garrison at Ulan-Ude is a significant military facility located in Russia's Siberian Military Zone. It represents one of the largest SAM garrisons inside of Russia, containing enough equipment to thoroughly modernize any lesser nation's air defense network.

OVERVIEW

The Ulan-Ude SAM garrison, sited roughly 28 kilometers ENE of Ulan-Ude, is an expansive facility composed of three main areas. Apart from the actual garrison and storage facility, there is an administrative and support area and a weapons storage area (WSA).

The general layout of the facility can be seen in the image below:
INFRASTRUCTURE

Various items of infrastructure can be identified at the Ulan-Ude SAM garrison. Power to the facility comes from external sources fed into the facility's substation by overland power lines. From the substation, power to the garrison itself is provided by a partially buried conduit. A POL storage facility is located south of the administrative and support complex, providing fuel for the garrison's vehicles as well as maintenance, security, and transportation vehicles serving the entire facility. While a network of minor paved and unpaved roads connect the complex with the outside world, the primary means of access is by rail. A rail transfer point for onloading and offloading equipment located adjacent to the garrison complex. A maneuver area is also located adjacent to the garrison complex, where wheeled and tracked vehicles can be put through their paces before dispersal to active units to pre-emptively identify any maintenance concerns.

The local infrastructure of the Ulan-Ude SAM garrison can be seen in the image below:
Regionally, there are numerous facilities which may serve to support the complex. 5 kilometers to the northwest, a power substation has been identified near the town of Onokhoy. This substation serves as the regional substation serving the SAM garrison. The garrison's power substation uses overland lines which lead directly to the Onokhoy substation. 6.5 kilometers to the west is a major rail transfer point. Equipment and cargo moved to and from the garrison complex travels down a dedicated rail spur which merges with the main line 2 kilometers east of the rail transfer point. Equipment being dispersed would travel down the rail spur, reach the rail transfer point, and likely either 1) continue along the main line, 2) be held for transfer to a different line, or 3) be offloaded and moved by road to an airfield in Ulan-Ude for airlift. Further to the southwest, at a distance of 9.5 kilometers from the main garrison complex, is a large POL storage facility. This facility could serve as the main holding area for POL in the region, with fuel being transferred by rail to the garrison when required to refill the complex's relatively minor capacity.

The regional infrastructure servicing the Ulan-Ude SAM garrison can be seen in the image below:
GARRISON DETAIL

The Ulan-Ude SAM garrison itself is a 530,000 square meter complex with numerous facilities designed to service, maintain, and disperse SAM equipment to operational units. The primary systems held at the facility are members of the S-300P series.

Apart from the holding areas and sheds, major identified locations include an equipment checkout pad, for verifying the operational status of equipment held at the facility before dispersal or during periodic maintenance, and a probable radar storage facility. The radar storage facility is the likely holding point for 64N6 (BIG BIRD) EW radar systems, as these systems have not been identified in open storage. The high-bay garage has an entrance at the northwest end of the building which has enough exterior clearance for a large vehicle such as the 64N6 transporter to maneuver out of the building and into the complex. No other buildings appear to have the necessary exterior clearance, suggesting that 64N6 components must be held in this facility.

Enough equipment for roughly fifteen S-300P series batteries can be seen in open storage at the facility. There are 68 5P85-1 TELs and 2 5N63 (FLAP LID A) radars associated with the S-300PT (SA-10A GRUMBLE), and 56 5P85S/D TELs and 9 5N63S (FLAP LID B) radars associated with the S-300PS (SA-10B GRUMBLE). Additionally, one 64N6 radar set and 9 40V6 mast assemblies can also be identified. SAM equipment is typically organized by battery, with the components for a complete battery being held in the same area. Apart from the S-300P series components, components for at least 4 S-125 (SA-3 GOA) batteries are also held at the facility, as well as numerous tactical SAM components.

The quantity of components held at the garrison is indicative of Russia's peacetime air defense posture. There are numerous inactive SAM sites in the nation, leading many casual observers to note that the network appears to be a shell of its former Cold War era self. This is not entirely accurate; the Russians have simply garrisoned a significant number of units, holding them in reserve until required. The equipment held at the Ulan-Ude garrison alone would be enough to significantly increase the effectiveness of any regional network. By holding these units in garrison, operating expenses can be saved while retaining the capability for future exploitation when required.

Identified areas and SAM components at the garrison complex can be seen in the image below. For the SAM components, which are identified by colored dots, the following color scheme has been used: S-300PT TELs are purple, S-300PS TELs are red, 5N63 radars are orange, 5N63S radars are yellow, 64N6 radars are blue, and 40V6 masts are green.
The garrison complex has numerous identifiable security measures to protect its holdings. The facility is entered using a primary entry control point which leads directly to the rail transfer point servicing the complex. A secondary entry control point likely serves as the entry for personnel and service vehicles. The complex is surrounded by a double fenceline, with an 18 meter dirt strip having been cleared between the fencelines. The exterior fenceline has lightposts placed every 32 to 35 meters, and four guard towers are situated at the corners of the fenceline in the dirt strip.

Security measures at the Ulan-Ude SAM garrison complex can be seen in the image below:
Located south of the main garrison is the weapons storage area for the complex. This facility serves as the primary holding area for the actual missiles to be employed by SAM systems held at the complex. Holding the weapons in a separate secure facility negates the possibility of a catastrophic explosion or fire damaging the SAM components. The WSA is accessed by a single road leading to an entry control point. Security is similar to that of the actual garrison complex, with a double fenceline separated by a defoliated dirt strip, various guard towers and lighposts surrounding the compound. The interior of the compound possesses numerous revetted holding areas, some of which contain storage buildings, others serving as open air holding pens.

Details of the Ulan-Ude WSA can be seen in the image below:
The following image depicts the likely steps for equipment to be dispersed from the garrison. First, equipment would be removed from holding areas and sent to the checkout pad. There, the equipment is spun up to determine its operational status. At this point minor maintenance would likely be conducted if required, and if enough discrepancies are noted it is likely that a different set of components would be removed from storage. Lastly, the components would be sent to the rail transfer point for transport.
CRITICAL NODES

The critical nodes for the Ulan-Ude SAM garrison are the main garrison complex and the rail transfer point. Eliminating the garrison complex itself removes the potential threat psoed by the garrisoned components, while eliminating the rail transfer point would make dispersal a far more time-consuming and tedious process. The WSA is not necessarily a critical node as there are sufficient holdings of missile rounds throughout the region and the nation to make up for any loss. Similarly, the power substation is not a critical node as its destruction would not cause any appreciable loss of ability to disperse equipment. The portable generators possessed by each individual battery could be used to power components for checkout.

INTELLIGENCE GAPS

The following intelligence gaps exist in the analysis of the Ulan-Ude SAM garrison complex:

1. The power station servicing the complex through the Onokhoy substation has not been identified.

2. Communications systems and facilities serving the complex have not been identified.

3. The source of potable water for the facility has not been identified.

SOURCES

-Satellite imagery provided courtesy of Google Earth

Site Analysis: New Stuff Coming Soon

Some of you might have noticed that this week's feature is scheduled to be on the Ulan-ude SAM garrison. Now, I know what you might be thinking: "Sean, what the hell, that's called an Image of the Week." Not so! This is going to be the first of a new type of feature I intend to do on a relatively regular basis called a Site Analysis. It'll be similar to the SAM Site Analysis pieces, or the look at the Iranian missile silos in Tabriz. Basically I'll be analyzing a military facility, describing the layout, the major features, any identifiable equipment, etc. Why did I pick Ulan-ude to start with? OK, you got me there: I'm cheating, it's a big SAM garrison with a lot of stuff that's easy for me to ID. It makes a relatively benign way to begin a new "series" of articles, letting me tinker around with the layout and the overall format without having to expend too much brainpower on the actual analysis. What this also means is that Site Analysis topics are now fair game for you to suggest as future topics for inclusion into the monthly schedule. So, that's what that is all about. Look for the first Site Analysis on the Ulan-ude SAM garrison later this week!