Accident FH-227 in Charleston

Fairchild Hiller FH-227B with registration number N712U (serial number 557) was released on August 3, 1967 , and on November 3 entered the American airline Piedmont Airlines. It was equipped with two Rolls-Royce Rda7-MK-532-7 turboprop engines equipped with Dowty Rotol propellers model R-193 / 4-30-4 / 50. The total operating time of the N712U at the time of the disaster was 2197 hours 3 minutes flying time ^[1] .

The crew of the aircraft consisted of two pilots and one flight attendant :

• The aircraft commander is 40-year-old Gene A. Sugg. At Piedmont Airlines from August 1, 1955, and in May 1965 he was promoted to F-27 commander. He had pilot qualifications for Martin 2-0-2 / 4-0-4 , Fairchild F-27 / FH-227 and NAMC YS-11 . He also qualified as an instructor pilot. A total of 6884 hours were flown, including 2,809 hours as F-27 / FH-227 aircraft commander. It flew 289 hours directly to the FH-227, including 79 hours in the last 30 days. To Canova County Airport Charleston has flown 35 times in the last 6 months. For the last 24 hours before the incident, he had a rest period of 10 hours 25 minutes ^[2] .
• The co - pilot is 34-year-old John F. Messick. At Piedmont Airlines since September 19, 1966. A total of 3722 hours flew, including 403 hours on F-27 / FH-227 aircraft. The raid over the past 30 days was approximately 70 hours. I flew 35 times to the Canova County airport in Charleston over the past 6 months. In the last 24 hours before the incident, he had a rest period of 10 hours 15 minutes ^[3] .
• Stewardess - 20-year-old Anna Pearl ( eng. Anna Pearl ) ^[4] .

Prior Circumstances

The aircraft performed a regular passenger flight PI-230 on the route Louisville - Cincinnati - Charleston - Roanoke . Departing from Louisville, Kentucky at 07:20 ^{[* 1]} , the ship soon landed safely in Cincinnati ( Ohio ), and at 08:05 with 34 passengers and 3 crew members on board flew to Charleston. The flight took place according to the rules of instrument flight at a level of 9000 feet (2700 m ) along the Victor 128 air corridor through York and under the control of the Indianapolis Dispatch Center ^[5] .

After passing the Milton intersection (10 miles (16 km ) west-north-west of the Charleston beacon), the dispatcher at 08:35 gave permission to descend and occupy an echelon of 5000 feet (1500 m ). The crew then contacted the Canova County airport take-off and landing controller (Charleston Tower) and requested the latest weather information: variable cloud cover, visibility 1/2 mile (4/5 km), fog, haze, [used ] lane 23, visibility in the 1/8 mile (1/5 km) lane. They reported from the plane that they expected to reach the airfield in 10-15 minutes, to which the dispatcher replied that by that time visibility in the strip could increase to half a mile ^[5] .

Approach

At approximately 08:41, the pilots made contact with the hike controller, reporting a height of 6,000 feet (1800 m ) and lowering to 5,000 feet (1,500 m ), after which the manager recognized the light on the aircraft on the radar screen, which was moving exactly along the established path, and then he instructed to continue along the 070 ° course, the vector of the waiting area at the distant drive beacon of the course-glide path system (ILS). An updated weather report at the airport was also transmitted: variable cloud cover, visibility 1/2 mile, fog, haze, visibility on the runway 23 zero, pressure for adjusting altimeters - 29.94 inches (760 mm) RT. Art. The crew also received instructions on how to complete the approach, the estimated time of which was determined to be 09:15, depending on weather conditions ^[6] .

At 08:50, flight 230 approached the long-distance drive, when the dispatcher instructed to turn right to a course of 140 °, go down and occupy a height of 2400 feet (730 m ), and at the same time conveyed that visibility on the strip had reached 7/8 miles. At 08:51, the Charleston Approach gave the following indication: You are seven miles [11 km] northeast of the long-distance drive. Turn right two zero zero [200 °]. Approved by ILS . The crew confirmed receipt of the instruction, and in response, the dispatcher warned that the glide path vector was disabled (disabled on August 8 due to a number of deviations in operation; it was again turned on on August 28 ^[7] ). To this from the plane passed: Okay, thanks ^[6] . The reduction was carried out at a vertical speed of about 620 feet (190 m ) per minute ^[8] . At 08:52, the approach dispatcher informed flight 230 that he was 5 miles (8 km) from the distant drive beacon, after which he instructed to switch to communication with the take-off and landing dispatcher ^[6] .

Holocaust

The landing controller at 08:52:53 ^[5] , without waiting for a report from the crew, gave permission to flight 230 to land. At 08:54:40, the pilots requested information about the wind, reporting that they had passed the long-distance drive. According to the latest data, the wind at this time was weak oncoming - 230 ° 4 knots. At 08:55:55 from the plane they asked: Do you have all the lights burning at full intensity? To this, the dispatcher said: Yes, of course. There at the end there is a little fog, but a mile and a half before the strip is already a strip free of it . This was the last radio communication with the N712U, and then the dispatcher suddenly saw a column of smoke appear near the end of the strip. Then an emergency was immediately declared, and American Airlines flight 701, operated by Lockheed Electra and entering Lane 23 after Flight 230, was sent to the second round ^[6] .

According to the testimony of an eyewitness who was half a mile from the entrance end of the strip, he saw how the fog hid the terrain in front of the airport, after which a plane flew into this veil, and then there was the sound of an impact. At a distance of 360 feet (110 m ) from the end of the strip, flying at an altitude of 885 feet (270 m ) above sea level, FH-227 at a speed of 120-123 knots caught tree tops, and after 110 feet (34 m ) at an altitude of 865 feet (264 m ) (approximately 33 feet (10 m ) below the aerodrome level) crashed into a steep hillside. Racing along it upwards of about 300 feet (91 m ), the FH-227 flew up again. At this time, at a taxiway at the beginning of lane 23, an airplane was waiting, the crew and passengers of which said that visibility on the lane at that time was actually close to zero, and the approach lights were not visible due to fog. Suddenly, a burning plane appeared from the fog, flying at an altitude of about 50 feet (15 m ), which then crashed to the ground at 08:56:53 on the opposite side of the strip, 300 feet (91 m ) away from them, collapsed and caught fire ^{[9 ] [10] [4]} .

The resulting ground fire destroyed a significant part of the fuselage and wing, before the fire brigade arrived in a couple of minutes, within 10 minutes, did not take it under control. Also, five surviving passengers who were thrown out were found at the scene: 20-year-old Judy Benhase, 19-year-old Sue Boskin, 19-year-old Barbara Schiller, 20-year-old Darrell Tripplett ( English Darrell Tripplett ) and 27-year-old Thomas Voignier ( English Thomas Voignier ). They were taken to Charleston Hospital, but the next day three people ^{[* 2]} died from their injuries ^{[11] [12] [4]} . In total, the disaster killed 35 people: 32 passengers and all 3 crew members ^[10] .

This is the first incident in the history of the Fairchild Hiller FH-227 ^[13] .

Weather conditions

Over the 20-year history of meteorological observations in the airport area, it was determined that August for this region is a period of fogs that thicken closer to midnight. And once the fog held for 19 days ^[14] .

The pilot of a light-engine aircraft, which took off from lane 23 shortly before the accident, reported that although visibility was good for a significant part of the lane's length, the first 300 feet (91 m ) from the initial end was covered with fog 150 feet (46 m ) thick . The co-pilot of flight AA-701, which followed the flight PI-230, said that he had seen the first half of the approach lights , but the second part of the lights, as well as the strip, were covered with fog. When the dispatcher ordered flight 701 to go to the second round, the airliner rose to 600 feet (180 m ) and flew over the airport, while its crew could see fragments of the N712U board through the fog, while the airport was still not visible ^[14] .

Exploring Debris

All the main parts of the aircraft were found at the scene of the accident, that is, before the collision with trees and ground, structural integrity was not violated. The control surfaces were restored, and their examination concluded that there were no failures in their work. The aircraft was in a landing configuration: the landing gear was released and fixed, the flaps were set to the maximum angle, the steering trimmer was shifted to an angle of 5 ° for cabling. Hydraulic and electrical systems had no signs of failure. Pitot tubes on both sides had no signs that they were clogged, which means the crew received the correct data on altitude and speed. The altimeters were restored, and the pressure on the instruments from the commander and co-pilot was set at 29.93 inches (760 mm) and 29.94 inches (760 mm) respectively. Art. respectively. The radio altimeters were badly damaged, but after replacing the destroyed components, they began to work properly. Course indicators from the commander and co-pilot showed 232 ° and 235 °, respectively. Radio compasses showed 235 ° and 232 °, respectively ^[15] .

Both engines separated at the moment of impact on the ground, and inside them they found dirt and branches that got in a collision with trees and a slope. The propeller blades were mounted at an angle of 16-17.8 °. An examination of the power plants led to the conclusion that the engines were operating normally, and there were no failures in them ^[15] .

Data Analysis

Flight 230 performed a normal approach until the final stage. But 6 seconds before a collision with the ground, the plane suddenly went into rapid decline, dropping even below the level of the airfield, until it crashed into the ground to the strip. Examination of the wreckage did not reveal any failures and malfunctions in the design of the aircraft, its systems and navigation devices. An analysis of data from flight recorders showed that just before the strike, the pilots tried to stop this decline. That is, it turns out that a qualified crew at an altitude of 200 feet (61 m ) above the aerodrome level intentionally began this decline, which became fatal ^[16] .

One of the fatal factors was the weather conditions at the airport. Morning fog at this time began to dissipate, so visibility in the approach area increased from ½ to 1 mile, and on the strip - from zero to ½ to 1 mile, that is, above the weather minimum, so landing was allowed. But a weak south-west wind actually only attributed this fog to the north-eastern part of the airfield - to the beginning of strip 23, where visibility was significantly limited. In addition, there was a slope from the approach approach to runway 23, along which this fog began to descend, while completely hiding the view from sight ^[17] . Although when following the fog above the airport was clearly visible, when it got into the fog, visibility already dropped sharply. The fog itself did not lie above the earth in an even layer, but with “knolls” 100–300 feet high (30–90 m), which means getting into it could be a complete surprise ^[18] .

According to the data of the flight recorder, during the approach, the aircraft decreased and occupied a height of 1225 feet (373 m ), which it kept about passing the near-driven radio beacon 18 seconds before the crash, after which it continued to decline at a vertical speed of 625 feet (191 m ) per minute, which it lasted for the next 12 seconds. It is worth noting the professionalism of the pilots, since the descent path was only slightly higher than the normal glide path, despite the fact that the slope vector of the glide path was disabled during this period. But 6 seconds before the impact, the car suddenly went into a steep decline with a vertical speed of over 2,000 feet (610 m ) per minute. The plane at that time was just above the middle of the approach lights and, possibly, flew into a thick fog, which caused the land to disappear from view ^[19] .

Thus, the situation deviated from normal in the last 6 seconds. In the absence of other evidence, this situation could logically be explained by the fact that the pilot disoriented in the fog began to intentionally perform a rapid decline in order to quickly see landmarks, while forgetting about the dangers of this decision ^[20] . But in conditions of low visibility, the pilot must have a distance in order to undertake an evasion maneuver. And if on ordinary piston aircraft the minimum visibility for approaching is set at 500 feet (150 m ), then on turboprop aircraft with speeds of over 125 knots (230 km / h) this distance is already small ^[21] . As studies conducted earlier in the UK showed, when the pilot is not familiar with situations of sharp deterioration in visibility, in the event of this occurrence, he may inadvertently translate the plane into a too steep decline, since focusing on the search for external landmarks cannot clearly monitor lateral vision for the horizon . Especially this situation becomes dangerous at low altitudes ^[22] .

Thus, when flight 230 unexpectedly fell into dense fog, the crew decided to lower as soon as possible to see the approach lights, for which, 6 seconds before the strike, it slightly reduced the engine operation mode. At an altitude of 175 feet (53 m ), high-intensity lights began to be visible through the fog, according to which the pilots decided that they were still quite high, so 4 seconds before the impact they further increased the descent rate. But in fact, this opinion turned out to be false, since the lights were not located on a horizontal platform, but on a slope. At the same time, the plane was already descending at a vertical speed of over 2000 feet per minute ^[23] .

There was also a version that the pilots did not really keep track of the speed, which became too low, after which the plane went into stall . However, the data of the recorders showed that over the past 26 seconds the airspeed did not decrease below 120 knots, that is, was much higher than the minimum allowable ^[24] .

If we assume that the visibility in the fog was 500 feet (150 m ), then, taking into account the trajectory of descent and the terrain, the commander had 3 seconds remaining from the moment he saw the ground before the collision. During this time, the pilot must have time to understand the situation, and then increase the engine mode, and then pull the helm towards yourself to avoid a collision with the ground. Given the time of 1-1½ seconds required to accelerate the engines to maximum revolutions, all these actions will take 2 seconds. In addition, during this maneuver, the aircraft dodged to the right so as not to crash into the supports of high-intensity lights. In this case, from the moment of the first appearance of the land in reserve, the pilots already had 3 and a half seconds, and the liner at this moment will be 90 feet (27 m ) higher than the approach lights, and therefore the avoidance maneuver can help correct the situation. But from the testimony of eyewitnesses it followed that the fog was much thicker, and the visibility was so small that when the crew noticed the ground, the amount of time would not even allow to undertake an evasion maneuver ^[25] .

The rules in force at that time (paragraph 91.117) required pilots that only if the approach lights, the strip itself, or other signs indicating the entrance end of the strip are clearly visible, then the crew can make a safe landing. If the ground or the lights of the campaign periodically disappear from view, then it was necessary to interrupt the approach and go to the second round ^[24] . However, having studied these rules, investigators from the National Council for Transport Safety found that they did not have a clear definition of the term “clearly visible”. These rules could be created for conditions close to ideal: a cloudy sky, or solid and rare fog. But in the case of flight 230, the pilot was faced with the fact that he observed the strip and the first half of the approach lights, but not the area at the entrance end, covered by low and dense fog, and therefore he could only decide on the basis of his subjective observation of the earth opinion. And an experienced pilot decided that once a strip is observed, it means that visual contact is established, so he continued to perform the approach ^[26] .

On August 21, 1969, the National Transport Safety Council published a report on the results of the investigation, in which it concluded that the crash of the N712U board occurred because the pilots did not recognize the vertical orientation in a timely manner, when they entered the final section of the approach thin but thick fog. The disoriented pilot, acting with the current rules, began to perform a rapid decline over the rising slope of the relief until he was at the point where it was no longer possible to safely interrupt the approach and leave for the second circle ^[28] .

To prevent such incidents, the National Transportation Safety Council sent a number of recommendations to the US Federal Aviation Administration ^{[29] [30]} :

• Introduce a ban on reducing to a height below 200 feet (61 m ) above the aerodrome level in rule 91.117 if the pilot does not observe the entrance end of the strip;
• To inform pilots of the dangers associated with entering low-fogging fog;
• To bring information about the optical illusions possible when they get into the fog layer at the final stage of the approach;
• As soon as possible, examine the determination by pilots of the inclination of the trajectory along the instruments in visual approach conditions;
• Set standards and guidelines for training simulators with simulated approach with more realistic low visibility conditions;
• To develop, and if financially possible to implement, improved high-intensity lights in the area up to 1000 feet (300 m ) from the entrance end of the strip, especially at airports where, according to the history of meteorological observations, there are frequent and thick fogs.

Comments

Sources

• Piedmont Airlines Fairchild-Hiller 227B, N712U, Charleston, West Virginia, August 10, 1968 . National Council for Transport Safety (August 21, 1969). Date of treatment January 18, 2015.

• August 10, 1968 - Piedmont 230 Cockpit Voice Recorder Database. Date of treatment January 18, 2016.
• Piedmont Crash My West Virginia Home In Photos. Date of treatment January 18, 2016.