Air Safety

In late February 23rd of this year, N123 (not his real call sign) – a Cessna 425 departed Phillipsburg, Kansas, (PHP) on an instrument clearance at 10,000, southwest bound for an airport in New Mexico. The route of flight originated in Denver Center airspace and took the aircraft south of Hill City VORTAC (HLC) and north of Garden City VORTAC (GCK).

South of HLC, at approximately 2:30 PM local time, N123 began to encounter icing and requested a lower altitude. The controller issued a clearance to descend to 8,000. At 8,000 feet, the direct route that N123 was flying will enter an area of no radar coverage. The controller changes the route of flight that will put N123 on an airway until radar contact can be reestablished, approximately 125 miles southwest of his current position. [1]

At approximately 2:36 PM, icing is continuing to accumulate and N123 requests a lower altitude. The controller issues descent clearance to 6,000. The controller also alerts me to the icing conditions N123 is encountering. A pilot report (PIREP) for moderate rime icing is generated and I notify the Operations Manager on duty that we have a low altitude aircraft in icing conditions in an area without radar coverage.

At 3:00 PM, N123 reports icing is still accumulating and request a lower altitude. I now view the situation with serious concern. Even though the pilot has not declared an emergency, I begin to treat it like it is one. A second controller is brought is to assist and coordinate. The Operations Manager is updated. We begin to look for alternates to suggest to the pilot. The controller issues descent clearance to 5,000, which is the minimum IFR altitude.

A check of the ASOS at Goodland, Kansas (GLD) shows a 200 foot broken ceiling. GCK is not much better with 400 foot overcast but visibility is less than one-half mile. Both show a temperature and dew point range that is prime for icing. Continued flight to the southwest will require a climb because of terrain. I view the only option for the pilot now is to land as quickly as possible.

The pilot reports reaching 5,000. No more icing is accumulating but he’s not losing any either. The aircraft is near Oakley, Kansas (OEL). A check of the weather indicates that although it is IFR at OEL, both the visibility and ceiling are above minimums, but not by much. Oakley seems the best option and I instruct the controller to ask the pilot if he has equipment onboard to make a GPS approach. N123 replies that he does and I have the controller offer that to the pilot as his best and safest alternative. The pilot accepts the offer to divert to Oakley then tells the controller that this is, “only the third time I’ve had to use my IFR ticket.” That comment raised a few eyebrows in the control room.

The pilot is asked to report over the initial approach fix. At 3:34 PM, N123 reports the runway in sight and lands safely several minutes later.

My thoughts: I did not have a chance to speak with the pilot personally but I have to wonder if he took the opportunity to get a weather briefing before departure. Since the pilot first encountered icing within 50 miles of his departure point and the icing conditions were forecast for several more hours and for at least 100 miles along his route of flight, I can only assume he did not.

It is my opinion that we acted in the best interest of the pilot by insisting he land his plane as soon as possible. The weather conditions, lack of radar coverage and active pilot reports (there were no other low altitude aircraft within 100 miles of N123 at that time) gave us few options. Every airport we checked reported except for OEL reported weather conditions below IFR minimums.

N123 lived to fly another day and was observed departing OEL the following morning.