1968 — Aug 10, Piedmont Air Flight 230 landing crash in heavy fog, Charleston, WV — 35

–35 Aviation Safety Network. Accident Description. Piedmont Air Flight 230, 10 Aug 1968.
–35 Kimura. World Commercial Aircraft Accidents 3rd Ed., 1946-1993, V.1. 4-11-1994, p. 3-11.
–35 NTSB AAR. Piedmont Airlines… N712U, Charleston, West Virginia, August 10, 1968.

Narrative Information

ASN: “Piedmont flight 230 was on an ILS [Instrument Landing System] localizer only approach to Charleston-Kanawha County Airport (CRW) runway 23 when it struck trees 360 feet from the runway threshold. The aircraft continued and struck up sloping terrain (+30deg) 250 feet short in a 4-5deg nose down attitude, slightly left wing down. The Fairchild continued up the hill and on to the airport, coming to rest 6 feet beyond the threshold and 50 feet from the right edge of the runway. A layer of dense fog (about 150 feet thick) was obscuring the threshold and about half of the approach lights. Visual conditions existed outside the fog area. (ASN. Piedmont Air Flight 230, 10 Aug 1968.)

NTSB Synopsis:

“Piedmont Airlines, Flight 230, Fairchild Hiller 227B, N712U, a regularly scheduled passenger flight, crashed and burned while on an approach to the Kanawha County Airport, Charleston, West Virginia, at approximately 0857 e.d.t., on August 10, 1968. The three crewmembers and 32 of the 34 passengers were fatally injured in the accident. The aircraft was ‘destroyed by impact and subsequent fire.”

“The flight was conducting an Instrument Landing System (ILS)…approach to Runway 23 when it crashed into a steep hillside approximately 250 feet short of the runway threshold and 33 feet below the threshold elevation.

“At the time of the accident, a layer of dense fog estimated to be 150 feet thick, was obscuring the threshold and approximately one-half of the approach light system for the runway…

“The Safety Board determines that the probable cause of this accident was an unrecognized loss of altitude orientation during the final portion of an approach into shallow, dense fog. The disorientation was caused by a rapid reduction in the ground guidance segment available to the pilot at a point beyond which a go-around could not be successfully effected.”

History of the Flight

Piedmont Airlines (PI) Flight 230, a Fairchild Hiller 227B, EJ712U, was a regularly scheduled passenger flight from Louisville, Kentucky, to Roanoke, Virginia, with en route stops at Cincinnati, Ohio, and Charleston, West Virginia. The flight departed Louisville Kentucky, at 072o on August 10, 1968, and proceeded routinely, its first intermediate stop, Cincinnati, Ohio.

At 0805, PI 230 departed Cincinnati on an Instrument Flight Rules (IFR) clearance to Charleston (Kanawha County Airport) via Victor Airways 128 south to York, thence Victor 128 to Charleston, to maintain 9,000 feet. The flight proceeded en route under the control of the Indianapolis Air Route Traffic Control Center and at 0835:20 was cleared to the Milton Intersection (10 miles west-northwest of the Charleston VORWC on Victor 128) and to descend to and maintain 5,000 feet. Just prior to this clearance, at 0835, PI 230 had called the Charleston Tower, requesting the latest weather. This was provided as: sky partially obscured, visibility 1/2 mile fog and smoke, Runway 23 visibility less than 1/8 mile. The flight responded, “. . .we’ll see you in about 10-15 minutes”, to which the tower replied, “Okay, looks by the time you get . . . down this way possibly the runway visibility will have improved to a half mile.”….

“At 0854:40, PI 230 requested a wind check and reported passing the outer marker inbound. The wind was reported as 230° at 4 knots. At 0855:55, PI 230 asked, “Have you got the lights turned all the way up?” The controller replied, “Sure do, a little fog right off the end there and it’s wide open after you get by that, it’s more than a mile and a half now on the runway.” This was the last
known radio communication with PI 230. Shortly after the foregoing transmission, the controller observed a column of smoke rising near the approach end of the runway and immediately activated the crash siren and called for the dispatch of airport emergency equipment. He then instructed American Airlines Flight 701, a Lockheed Electra also on an ILS approach behind PI 230, to execute a missed-approach procedure.

“One witness, who was located in the valley approximately 1/2 mile from the approach end of the runway, stated that at the time of the accident a fog bank was obscuring the hilltop on which the airport is located. Although he did not see the aircraft at any time during the approach, he stated that as the aircraft approached his position the engines sounded noma1 and that his first indication of the accident was when he heard the sound of an explosion.

“The pilot and a passenger of an aircraft awaiting takeoff clearance on a taxiway adjacent to the approach end of Runway 23 stated that the visibility in the fog at the end of the runway was ‘close to zero’ and that although they were looking in the direction of the incoming aircraft, they could not see the airport approach lights or the approach light structure because of the fog obscuration. They stated that their first observation of PI 230 was when it suddenly appeared out of the fog, approximately 50 feet in the air over the end of the runway. At this time the aircraft was on fire and falling rapidly toward the ground. The wreckage came to rest on the opposite side of the runway about 300 feet from their position.

“It was determined that the aircraft struck the steep hillside about 250 feet short of the runway threshold at an elevation of 865 feet m.s.l. (approximately 33 feet below the elevation of the threshold). The aircraft then careened up and over the side of the hill and onto the airport, coming to rest off the right side of Runway 23.

“The accident occurred at 0856:53 during daylight conditions….

“The three crewmembers and 29 passengers were fatally injured at impact. These fatalities were attributable to severe trauma. Five survivors were removed from the wreckage area and taken to hospitals in Charleston. Three of the five survivors succumbed the following day. All five of the initial survivors had been thrown clear of the aircraft cabin during the impact sequence….

Analysis

“Evaluation of all of the evidence obtained during the investigation of this accident indicates that the flight was operationally routine until the final phase of the approach to the Charleston Airport. A t this point in the approach, approximately 6 seconds from impact, the aircraft commenced a rapid descent which resulted in contact with the terrain short of the runway threshold. Examination of the aircraft structure, components, and systems revealed no indication of any in-flight failure, malfunction, or other abnormality that would have caused or contributed to an unwanted descent. Evidence of an engine power application as well as the type of damage exhibited on the aircraft structure, indicates that the crew attempted to “pull up” just prior to impact.

“In view of these findings, it is obvious that the causal area of this accident concerns the operational factors involved in the conduct of the approach and the particular circumstances that would influence a qualified pilot to initiate a steep descent when only 200 feet above the airport level, and to continue it to a point above the ground where recovery could not be attained….

“…until 6 seconds before the accident, the approach can be considered a routine and acceptable operation. The only logical conclusion, in the absence of any evidence to the contrary, is that some phenomenon associated with the reduced visibility upon entering the fog affected the pilot in such a manner that he steepened the descent to the point where recovery could not be effected….

“…it has been shown that the sudden reduction in visual range on entering the fog may be misinterpreted for a pitch change in the noseup direction. Pilots unfamiliar with this phenomenon will, therefore, tend to steepen their angle of descent when they encounter this situation….

“The Safety Board determines that the probable cause of this accident was an unrecognized loss of altitude orientation during the final portion of an approach into shallow, dense fog. The disorientation was caused by a rapid reduction in the ground guidance segment available to the Pilot, at a point beyond which a go-around could not be successfully effected.

Recommendations

“Subsequent to this accident the following recommendations were forwarded by the Safety Board to the Administrator of the Federal Aviation Administration:

(1) That section 91.117 and section 121.649 of the Federal Aviation Regulations be amended to prohibit any approach below 200 feet above field level unless the pilot has the runway threshold in sight and require that he continue to have same in sight during the remainder of the approach.

(2) That the Federal Aviation Administration bring to the attention of all instrument pilots the hazards associated with shallow fog penetration. This might be accomplished in the form of an Advisory Circular and/or by publication in the Airman’s Information Manual. Reference to training films, such as the ICAO production of “Fog and Runway Lighting,” and the sources from which such films could be obtained, should be included.

(3) That information on shallow fog penetration, the effect upon the guidance segment, and the potential illusions that can be created be included as mandatory items in air carrier training programs and in the curriculum of FAA approved Instrument Flight Schools.

(4) That the Federal Aviation Administration pursue as expeditiously as possible their research project to determine the instrumentation necessary to provide slant visual range information.

(5) That the Federal Aviation Administration establish standards and specifications for, and encourage the development of, synthetic trainers capable of providing realistic low visibility approach simulation.

(6) That improved approach zone lighting in a t least the last 1,000 feet of the approach preceding the runway threshold be programmed for installation on a priority basis at airports having a climatological history of frequent heavy fog conditions when and if financial conditions permit.” (NTSB AAR. Piedmont Airlines… N712U, Charleston, West Virginia, Aug 10, 1968.)

Sources

Aviation Safety Network. Accident Description. Piedmont Airlines Flight 230, 10 Aug 1968. Accessed 3-2-2009 at: http://aviation-safety.net/database/record.php?id=19680810-0

Kimura, Chris Y. World Commercial Aircraft Accidents 3rd Edition, 1946-1993, Volume 1: Jet and Turboprop Aircrafts. Livermore, CA: Lawrence Livermore National Laboratory, Risk Assessment and Nuclear Engineering Group. 4-11-1994.

National Transportation Safety Board. Aircraft Accident Report. Piedmont Airlines, Fairchild-Hiller 2276, N712U, Charleston, West Virginia, August 10, 1968. Washington, DC: NTSB, August 21, 1969, 50 pages. At: http://www.airdisaster.com/reports/ntsb/AAR69-06.pdf