Instrument-rated pilots know that every ILS approach has a decision height — the point at which a choice must be made to either continue the descent or execute a missed approach.
On Oct. 7, 2005, the pilot of a Beech Bonanza was killed when he strayed left of the localizer course and descended below decision height while flying the ILS to Runway 27 at Pike County-Hatcher Field (PBX) in Pikeville, Ky.
Prior to departure, the pilot called the Louisville Flight Service Station, advised the briefer of his route of flight (Paducah, Kentucky, to Pikeville), and asked about "echoes" in eastern Kentucky. Weather in the area included light to moderate rain over his planned route, with ceilings of 700 feet broken and 1,500 feet overcast, and visibility of four miles. Before hanging up, the pilot filed an IFR flight plan.
En route to the Pikeville area, the pilot was in contact with Indianapolis ARTCC. At 3:27 p.m., he advised ATC that he had the current weather for Pike County and requested the ILS Runway 27 approach. ATC then vectored the Bonanza for the approach. At 3:46 p.m., the flight was cleared for the ILS Runway 27 approach; the pilot acknowledged the clearance and reported established on the localizer two minutes later. He was then advised that a frequency change (to the local CTAF) was approved and that he should close his flight plan with Indianapolis ARTCC after landing.
The Bonanza's radar track showed that at 3:50 p.m., the aircraft was at an altitude of 2,300 feet msl one mile from the Runway 27 threshold and drifting left of course. One minute later — the last time the Bonanza was seen on radar — it had descended below 1,800 feet and was one mile south of the airport. The wreckage was found 100 feet below the peak of a mountain, at 1,520 feet msl. The decision height for the ILS approach is 1,664 feet msl — 124 feet above the accident site.
Two pilots on the ground heard the Bonanza approach the airport before flying past it to the south. They both estimated the ceiling to be variable between 200 and 300 feet overcast with visibility of three-quarters of a mile.
The accident pilot had logged a total of 527 flight hours. He had also recorded 323 hours of actual instrument experience, though "...a review of an excerpt from the logbook revealed that the pilot had logged all of the flight time as actual instrument."
The NTSB determined the cause of this accident to be the pilot's failure to follow the published instrument approach, which resulted in controlled flight into terrain.
The regulations (FAR 91.175 (c)) are clear regarding descent below the decision height on a precision approach. Not only did the pilot descend below the decision height without the required visual references, he navigated left of the localizer and should have executed the missed approach if the CDI had reached full-scale deflection.
The lesson for instrument-rated pilots is clear: Instead of trying to salvage a bad approach, break off, contact ATC, and try again.
Accident reports can be found in ASI's accident database.
Posted Wednesday, October 03, 2007 12:07:18 PM