Too Good to Be True

SU-25 attack jets on the ramp at Sunchon AB, North Korea. Sunchon is one of the few NK airbases where fighters are stored above ground (Google Earth photo via Flickr)

The U.K. Sunday Times reports that North Korea is completing a 6000-foot, underground runway that would protect fighter jets from attack until they take off, through the mouth of a tunnel.

As the Times' Michael Sheridan reports:

The 6,000ft runway is a few minutes’ flying time from the tense front line where the Korean People’s Army faces soldiers from the United States and South Korea.

The project was identified by an air force defector from North Korea and captured on a satellite image by Google Earth, according to reports in the South Korean press last week.

It is one of three underground fighter bases among an elaborate subterranean military infrastructure built to withstand a “shock and awe” assault in the first moments of a war, the defector said.

The runway, reminiscent of the Thunderbirds television series, highlights the strange and secretive nature of the regime that provided the expertise for a partially built nuclear reactor in Syria, film of which was released by the CIA last week.

The paper's account provides no additional details on the underground base, which it compared to the subterranean facility in Thunderbirds, the classic, 1960s British sci-fi TV series. But there's only one problem with the "runway-inside-a-mountain" that supposedly exists in North Korea; the story simply isn't true.

Tales of a massive, underground jet base in the DPRK have been making the rounds for years, and like many myths, they contain elements of truth. For example, virtually all North Korean Air Force (NKAF) bases have underground facilities (UGFs), but they're--typically--a combination parking area and maintenance hangar, carved inside a mountain.

Many of the UGFs are quite large; at many bases they can accomodate a full aircraft regiment, as many as 45 jets. The underground shelters offer hardened protection from enemy air attack and allow North Korean technicians to service and load their jets without being detected. But to launch, aircraft must depart the UGF, using one of adits that lead to the outside taxiway and runway. Each of the portals has a massive blast door, providing more protection against enemy airstrikes or missile attacks.

Pyongyang's UGF project has been underway for decades. In fact, it's something of a rarity to find a NKAF base where underground facilities aren't used, or simply don't exist. One of the installations that fall in that category is Sunchon AB, near Pyongyang. Sunchon is home to the newest aircraft in the North Korean inventory, the MiG-29 Fulcrum and the SU-25 Frogfoot.

Fighters at the base are stored in above-ground aircraft shelters, similar to those at airfields in Europe and the Middle East. Construction of the shelters at Sunchon was prompted by an important discovery; the moisture and humidity in UGFs created havoc with the jets' avionics. Older North Korean fighters with tube-based electronics (MiG-15/17/19/21s) are less affected by high moisture levels, and are usually stored in underground bunkers.

Underground facilities are also found at bases supporting other aircraft, including the three mentioned in the Times' story. Incidentally, those installations have been around for years, and they serve (primarily) as forward bases for AN-2 Colt biplanes, used as an insertion platform for North Korea's massive special operations forces. Prior to an attack against the south, the AN-2s would arrive at the forward airfields, allowing local SOF units to deploy on the aircraft.

As for the underground runway, it's impractical for a number of reasons. First, creating the airstrip, an "overhead" area and adjacent parking and maintenance chambers would require a huge excavation job, producing massive piles of rock and dirt (known as spoil in the imagery intelligence business). Those piles would have appeared long before their recent detection by "Google Earth."

Then, there's the actual business of taking off from an underground runway. Needless to say, there is no margin for error; the slightest mistake could lead to a conflagration that would wipe out scores of aircraft. Additionally, the large tunnel opening (the departure point for the fighters) would be more difficult to camouflage and conceal. Targeting the exit point would make it easy to shutdown the runway, destroying more equipment--and personnel--inside the UGF.

In fairness, the Times' account isn't completely false. Much of the information about WMD cooperation between Syria and North Korea is factual and timely. But on the subject of that mythical, underground fighter base, the British paper is far off the mark.