In a legal opinion, Luke Air Force Base’s top lawyer says that civilian use of the practice ILS approach at AUX-1 airfield northwest of Phoenix is “unauthorized” and measures should be taken to prevent its use by anyone other than military pilots.

“The Air Force does face potential liability connected with this practice,” wrote Capt. Bradley J. Sauer, chief of Operations and Administrative Law, in a Nov. 14 memorandum to Luke officials. The USAF’s Staff Judge Advocate, Lt. Col. Thomas L. Cluff Jr., also signed off on the memo.

AUX 1 is an airfield west of Phoenix Deer Valley Municipal Airport, just north of the White Tank Mountains, that is not usable for takeoffs and landings. However, the Air Force has stationed an Instrument Landing System at the airfield in order to allow military pilots to develop and practice instrument skills.

For many years, the civilian community has also taken advantage of the unpublished ILS procedure, and flight instructors have taken their students to AUX-1 to practice.  The field is ideal for practice on weekends because it is relatively isolated and free of complex airspace operations.

But, the Air Force, in its memorandum, expresses that there is a safety concern posed by joint military and civilian use.

“During periods of non-use by Luke AFB, the ILS could fail or malfunction and, as a result, a civilian aircraft could crash while engaging in unauthorized instrument training,” Sauer writes. “There exists the possibility of concurrent but unauthorized use by civilian aircraft, which could cause either the military or civilian aircraft, or both, to collide or crash.”

Sauer recommends that Luke shut off the ILS whenever it is not being used by the military in order to prevent civilian use.

Sauer also is recommending that the Federal Aviation Administration issue a Notice to Airmen stating that the use of Aux-1 by civilian pilots is not permitted.

Read a PDF copy of the memorandum. (Requires Adobe Reader.)