Air Safety

The National Transportation Safety Board determined that the probable cause of this accident was the total and unique loss of thrust from both engines while the aircraft was penetrating an area of severe thunderstorms. The loss of thrust was caused by the ingestion of massive amounts of water and hail which in combination with thrust lever movement induced severe stalling in and major damage to the engine compressors.

Major contributing factors included the failure of the company’s dispatching system to provide the flight crew with up-to-date severe weather information pertaining to the aircraft’s intended route of flight, the captain’s reliance on airborne weather radar for penetra­tion of thunderstorm areas, and limitations in the Federal Aviation Administration’s air traffic control system which precluded the timely dissemination of real-time hazardous weather information to the flightcrew.

Factual information

History of flight. On April 4, 1977, Southern Airways, Inc. Flight 242, a DC-9-31, (N1335U) operated as a scheduled passenger flight from Muscle Shoals, Ala, to Atlanta, Ga, with an intermediate stop at Huntsville, Ala. Flight 242 departed Muscle Shoals at 1521 (all times herein are eastern standard, based on the 24-hour clock) and landed at Huntsville about 1544.

About 1554, Flight 242 departed Huntsville on an instrument flight rules (IFR) flight plan for the Hartsfield-Atlanta International Airport; there were 81 passengers and four crew members aboard. The flight’s route was direct to the Rome VOR (a very high-frequency omnidirectional range navigational aid located about 72naut mi east­ southeast of Huntsville and 46 naut mi northwest of the Atlanta air­ port) and then a Rome runway 26 profile descent to Atlanta. Its es­timated time en route was 25 minutes, and its requested en route altitude was 17,000ft (all altitudes herein are mean sea level unless otherwise specified).

At 1554:35, Flight 242 established communications with Huntsville departure control and at 1554:39, the controller cleared the flight to climb to 17,000ft. At 1555:14, the controller cleared the flight to proceed directly to the Rome VOR. According to the cockpit voice recorder (CVR), at 1555:58 the captain remarked, “Well the radar is full of it, take your pick”. At1556:00, the controller told Flight 242 that his radarscope was showing heavy precipitation and that the echos were about 5 naut mi ahead of the flight. Flight 242 responded, “Okay. . . we’re in the rain right now. . . it doesn’t look much heavier than what we’re in does it?” At 1556:12, the controller said,”. . . I got weather cutting devices on which is cutting out the precip that you’re in now. . . however, it’s not a solid mass, it . . . appears to be a little bit heavier than what you’re in right now. ” Flight 242 replied. “Okay, thank you”.

At 1556:37, the first officer, who was flying the aeroplane, said, “I can’t read that, it just looks like rain, Bill. What do you think? There’s a hole. ” The captain responded, “There’s a hole right here. That’s all I see”. He added, “Then coming over, we had pretty good radar. I believe right straight ahead . . . there the next few miles is about the best way we can go”.

At 1557:36, the controller said,”. . . you’re in what appears to be about the heaviest part of it now, what are your flight conditions”. Flight 242 replied, ” . . . we’re getting a little light turbulence and. . . I’d say moderate rain”. At1557:47, the controller acknowledg­ ed Flight 242’s report and told the flight to contact Memphis Centre.

At 1558:10, Flight 242 established communication at Memphis Air Route Traffic Control Centre (Memphis Centre). At 1558:32, the captain said, “As long as it doesn’t get any heavier we’ll be all right”. The first officer replied, “Yeah, this is good”.

At 1558:26, the Memphis Centre controller advised the flight that a SIGMET (Significent Meteorological Information – A weather advisory concerning weather significant to the safety of all aircraft. It includes tornadoes, lines of thunderstorms, embedded thunderstorms, large hail, severe and extreme turbulence, severe ic­ ing, and dust or sandstorms) was current for the vicinity of Tennessee, southeastern Louisiana, Mississippi, northern and western Alabama, and adjacent coastal waters, and advised them to monitor VOR broadcasts within a 150-naut mi radius of the SIGMET area. At 1558:45, the controller told Flight 242 to contact Atlanta Air Route Traffic Control Centre (Atlanta Centre). At 1559:00, the captain said, “Here we go . . . hold ’em cowboy”.

At 1559:06, Flight 242 established communications with Atlanta Centre (Sector 39) and stated that it was “out of eleven for seventeen”. The controller replied,”. . . Roger, expect Rome runway 26 profile descent”. Flight 242 acknowledged the controller’s transmission. Between 1559:18 and 1602:03, the Atlanta Centre con­ troller conversed with TWA Flight 584 about its deviations eastward around thunderstorms between Chattanooga, Tenn, and Rome, Ga. At 1600:30, the sound of rain was recorded on Flight 242’s CVR. At 1602:57, the captain of Flight 242 said, “I think we’d better slow it up right here in this. . . “. The first officer replied, “Got ya covered”.

At 1603:01, an Atlanta Centre controller (sector 40) contacted an Eastern Airlines flight, which had just crossed the storm area northwest of Rome, and asked, “How would you classify your ride through that line up there? You recommend anyone else come through it?” The flight answered that “it was not too comfortable but we didn’t get into anything we would consider the least bit hazar­ dous”. At 1603, Flight 242 was told to contact Atlanta Centre (sector 40). About 11 seconds later, the sound of light rain was recorded on the CVR. At 1603:20, Flight 242 established communications with Atlanta Centre on the new frequency and said, ” . . . level at seventeen”. At 1603:48, the captain said, “Looks heavy, nothing’s go­ ing through that”. Six seconds later, he said, “See that”. The first of­ ficer said, “That’s a hole, isn’t it?” The captain replied, “It’s not show­ ing a hole, see it?” At1604:05, the sound of rain was recorded on the CVR, and 3 seconds later the first officer asked, “Do you want to go around that right now?” At 1604:19, the captain said, “Hand fly it about 285kt,” and first officer responded, “285”.

At 1604:30, the sounds of rain and hail were recorded, and 20 seconds later Flight 242 reported to Atlanta Centre that the flight was reducing speed. At 1605:53, the first officer said, “Which way do we go cro s here or go out – I don’t know how we get through there, Bill”. The captain replied, “I know you’re just gonna have to go out . . . “. The first officer said, “Yeah, right across that band”. At 1606:01, the captain said, “All clear left approximately right now; I think we can cut across there now”. At 1606:12, the first officer said, “All right, here we go”.

Between 1604:42 and 1606:20, Atlanta Centre was coordinating with TWA584 about its route and altitude to intercept the Atlanta VOR 313-deg radial inbound. At 1606:30, the controller said, “I show weather up northwest of that position, north of Rome, just on the edge of it . . . maintain 15,000”. TWA 584 replied, “Maintain 15,000, we paint pretty good weather at 1 or 2 o’clock”.

At 1606:41, the first officer on Flight 242 said, “He’s got to be right through that hole about now”. At about the same time, Atlanta Centre cleared Flight 242 to descend to and maintain 14,000ft. At 1606:46, the captain said, “Who’s that?”, and the first officer replied, “TWA”. At 1606:53, the captain reported to Atlanta Centre, “242 down to 14”. About the same time, the sound of heavy hail or rain was recorded onthe CVR. The sounds continued to 1607:57, at which time the CVR ceased to record for 36 seconds; it began operation again at 1608:33, and the sound of rain continued for another 40 seconds.

Between 1607:00 and about 1608:01, Atlanta Centre made four transmissions to Flight 242; none was acknowledged. About 1608:34, Atlanta Centre said, “Southern 242, Atlanta”. A, 1608:37, the first of­ ficer said, “Got it, got it back Bill, got it back”. At 1608:42, Flight 242 told Atlanta Centre to “standby”. At 1608:49, Atlanta Centre transmitted, “Roger, maintain 15,000 if you understand me, maintain 15,000, Southern 242”. At 1608:55, Flight 242 replied, “We’re trying to get it up there”.

At 1609:15, Flight 242 reported to Atlanta Centre, “Okay. . . we just got our windshield busted and. . . we’ll try to get it back up to 15, we’re14”. At 1609:36, the first officer said, “Left engine won’t spool,” and Flight 242 reported to Atlanta Centre, “Our left engine just cut out”. Atlanta Centre replied, ” . . . Roger, and lost your transponder, squawk 56i3″. At 1609:43, the first officer said, “I’m squawking 5623, tell him I’m level 14”.

At 1609:59, the captain said, “Autopilot off,” and the first officer replied, “I got it, I’ll hand fly it”. At 1610:00, Atlanta Centre cleared Flight 242 to descend to 13,000ft. At 1610:04, the first officer. said, “My . . . the other engine’s going too . . . ,” and at 1610:05, Flight 242 reported to Atlanta Centre,”. . . the other engine’s going too”. Atlan­ ta Centre replied, ” . . . say again”. Flight 242 said, “Standby, we lost both engines”.

At 1610:14, the first officer said,”All right Bill, get us a vector to a clear area”. At 1610:16, Flight 242 told Atlanta Centre, “Get us a vec­ tor to a clear area Atlanta”. Atlanta Centre replied,” . . . continue pre­ sent south-eastbound heading, TWA’s off to your left about 14 mi at 14,000 and says he’s in the clear”. Flight 242 replied, “Okay”.

At 1610:27, Flight 242 asked Atlanta Centre, “Want us to turn left?” The centre replied, ” . . . contact approach control 126. 9 and they’ll try to get you straight into Dobbins” (Dobbins AFB is located about 33 naut mi east-southeast of the Rome VOR). At 1610:36, the first officer said, “Give me – I’m familiar with Dobbins, tell them to give me a vector to Dobbins if they’re clear”. At 1610:38, Flight 242 asked Atlanta Centre, “Give me a vector to Dobbins if they’re clear”. The centre replied,” 126. 9, they’ll give you a vector to Dobbins”.

At 1610:45, Flight 242 replied, “269, Okay”.

At 1610:50, the first officer said, 0lgnition override, it’s gotta work . . . “. At 1610:52, an Atlanta Approach Control transmission to Lear Jet 999M was recorded on. Flight 242’s CVR; at 1610:56, the CVR ceased operation for 2 minutes and 4 seconds. Between about 1611:17 and 1612:50, Atlanta Centre made three transmissions to Flight 242. About 161:00, Atlanta Approach Control made one transmission to Flight 242; 10 seconds later, TWA 584 called Flight 242. No responses were recorded.

At 1613:00, the CVR resumed operation, and at 1613:03 the cap­ tain said, “There we go”. The first officer responded, “Get usa vector to Dobbins”. At 1613:04, Flight 242 transmitted to Atlanta Approach Control, ” . . . Atlanta, you read Southern 242?” Approach Control replied, “Southern 242, Atlanta. . . go ahead”. Flight 242 said, ” . . . we’ve lost both engines, how about giving us a vector to the nearest place, we’re at 7000ft”. At 1613:17, Approach Control replied, “Southern 242, Roger, turn right heading 100 deg, will be vectored to Dobbins for a straight-in approach Runway 11 your position is 15, correction 20 mi west of Dobbins at this time”. Concurrent with this transmission, the first officer said, “What’s Dobbins’ weather, Bill? How far is it? How far is it?” Flight 242 transmitted, “Okay 140 deg heading and 20 mi”.

At 1613:35, Atlanta Approach Control directed, ” . . . make a heading of 120, Southern 242, right turn to 120 deg”. Flight 242 replied, “Okay, right turn to 120 and . . . you got us our squawk, haven’t you, on emergency”. Concurrent with this transmission, the first officer said, “Declare an emergency, Bill”. At 1613:45, Approach Control replied,” I’m not receiving it but radar contact, your posi­tion is 20 mi west of Dobbins”. Flight 242 replied, “Okay”.

At 1614:03, the first officer said, “Get those engines. . . “. At 1614:24, Flight 242 transmitted to Approach Control, “All right, listen, we’ve lost both engines, and . . . I can’t. tell you the implications of this. . ·. we only got two engines, and how far is Dobbins now?” Ap­proach Control replied, ” 19 mi”. Flight 242 transmitted, “Okay, we’re out of. . . 5800, 200kt”. At 1614:45, Approach Control asked, “Southern 242, do you have one engine running now?. ” Flight 242 replied, “Negative, no engines”.

At 1615:04, the captain said, “Just don’t stall this thing out”. The first officer replied, “no I won’t,’. The captain said, “Get your wing flaps,” and the sound of lever movement was recorded. At 1615:11, the first officer said, “Got it, got hydraulics, so we got”. The captain replied, “We got hydraulics”. At 1615:17, the first officer said “What’s the Dobbins weather?” At 1615:18, Flight 242 Approach Control, “What’s your Dobbins weather?” Approach Control said, “Standby”. At 1615:46, Approach Control said, “Southern 242, Dobbins weather is 2000 scattered, estimated 7000 overcast, visibility 7 mi”. Flight 242 replied, “Okay, we’re down to 4600 now”. Approach Control responded, “Roger, and you’re approximate’. . . 17 mi west of Dob­ bins at this time”. At 1616:05, Flight 242 said, “I don’t know whether we can make that or not”.

At 1616:11, the first officer said,”. . . ask him if there is anything between here and Dobbins?” The captain said, “What?” and the first officer repeated his request. At 1616:25, Flight 242 asked Approach Control, ” . . . is there any airport between our position and Dob­ bins?” Approach Control replied, ” . . . no sir, closest airport •is Dob­ bins”. At 1616:34, Flight 242 said, “I doubt we’re going to make it, but we’re trying everything to get something started”.

Approach Control replied, “Roger, well there is Cartersville, you’re approximately 10 mi south of Cartersville, 15 mi west of Dob­ bins”.

At 1616:45, Flight 242 asked Approach Control, “Can you give us a vector to Cartersville?” Approach Control replied, “All right, turn left, heading of 360, be directly. . . direct vector to Cartersville”. Flight 242 said, “360, Roger”.

At 1616:53, Flight 242 asked Approach Control, “What’s the runway heading?” Approach Control replied, “Standby”. Flight 242 then asked,” And how long is it?” Approach Control replied, “Stand­ by”.

At 1617:08, the captain said, ” . . . I’m picking out a clear field”. The first officer replied, “Bill, you’ve got to find me a highway”. The captain said, “Let’s get the next clear open field”. The first officer said, “No . . . “. At 1617:35, the captain said, “See a highway over – no cars”. The first officer said, “Right there, is that straight?” The captain replied, “No”. The first officer said, “We’ll have to take it”.

At 1617:44, Approach Control transmitted, “Southern 242, the runway configuration . . . at Cartersville is. . . 360 and running north and south and the elevation is 756ft and . . . trying to get the length now – it’s 3200ft long”. At 1618:02, Flight 242’s last transmission to Approach Control was recorded: ” . . . we’re putting it on the highway, we’re down to nothing”.

From 1618:36 to 1618:43, crash sounds were recorded on the CVR.

According to one of the passengers, a commercially licensed pilot who was seated on the left side of the aeroplane just forward of the left engine intake, the flight was routine until the aircraft en­ countered severe turbulence followed by very heavy precipitation, a lightning strike on the left wingtip, and hail. The hail increased in in­ intensity and size; then the right engine quit and the left engine quit shortly thereafter.

He thought the cabin lights went out shortly after the lightning strike, but before the hail began.

Additionally, almost simultaneous with the turbulence, he notic­ ed that the power was reduced on the engines. He estimated that the turbulence lasted from 1 to 2 minutes, the heavy precipitation lasted from 45 to 60 seconds, and the hail lasted from 45 to 60 seconds.

The engines quit shortly after the hail ceased; just before the right engine quit, he heard loud popping sounds from an area ahead of the engine.

Similarly, just before the left engine quit, he heard sounds of the engine surging and loud popping. He also noticed that the inlet fair­ ing in the centre of the left engine was dented. After the engines quit, he heard sounds that he associated with attempts to start the auxiliary power unit (APU) followed by sounds of the unit in operation.

The two flight attendants recalled details similar to those express­ ed by the passenger.

At about 1615, several witnesses in Rockmart, GA, saw Flight 242 fly­ ing over Rockmart in a westerly direction. The aircraft made a left turn and flew back toward the east. They heard no engine sounds and saw nothing peculiar about the aircraft.

The aircraft crashed during daylight hours, at an elevation of 1020ft, and at latitude 33 deg 57 min 45 sec and longitude 84 deg 47 min 13 sec.

Injuries and damages

Injuries to persons. Fatal: crew, 2; passengers, 60; others 8. Serious: crew, 1; passengers, 21; others, 1. Minor/none: crew, 1.

Damage to aircraft. The aircraft was destroyed.

Other damage. A combination grocery store-gasoline station was destroyed by fire. A truck and five automobiles were destroyed, and an automobile and a house were substantially damaged.

Additionally, numerous trees, shrubs, lawns, utility poles, powerlines, mailboxes, highway signs, and fences were damaged.

Medical and pathological information. Post mortem ex­ aminations of the flight crew and passengers were made to determine injuries and to aid in identification. Toxicological examinations of the flight crew revealed no ethyl alcohol. The tests for drugs were in­ conclusive because the specimens tested were either unsuitable or insufficient for analy is. The tests for hemoglobin (%), car­ oxyhemoglobin (gm %), and hydrogen cyanide ug/ml(microgram/millilitre) disclosed the following respective levels in the captain and first officer: 14. 1 and 8, 0. 4 and 5. 8 and O and 0. Both flight crew members died of extensive trauma; they were not burned and there was no evidence they inhaled smoke.

Twenty passengers died of burns and smoke inhalation; their blood contained various levels of carbon monoxide saturation, the highest level of which was 38%. Autopsies revealed no significant in­ juries although some injuries could have been obscured by the severe burns. Thirty-one passengers died of extensive traumatic in­ juries. Most of these consisted of crushing of the upper torso and head. There was no evidence of soot or smoke inhalation in these passengers.

Nine passengers sustained trauma combined with burning or smoke inhalation. In addition to the traumatic injuries, these passengers displayed evidence of smoke inhalation and increased levels of carbon monoxide in the blood. Also, the levels of hydrogen cyanide found in blood samples varied; the highest level was 5. 5 ug/ml.

The surviving passengers sustained a variety of serious injuries. Many were burned about the head, face, hands and lower legs. Three passengers had fractured spines. Arm, hand and leg fractures were common and most passengers had numerous abrasions and con­ tusions.

Both flight attendants had sprained necks and both had con­ tusions and abrasions of the legs. One flight attendant also had con­ tusions and abrasions on both hands.

Fire. Volunteer firemen who witnessed the crash of N1335U from a nearby fire station in New Hope responded immediately to the crash scene with two fire trucks. The firemen’s first efforts were directed toward a fire in a combination grocery store-gasoline station and scattered fires among the automobiles. The fire in the store was apparently ignited by short-circuited powerlines and was fed by gas­ online from the damaged pumps. One fire truck was used to fight this fire while the other truck was used to fight the fire in the mid and aft sections of the aircraft. There was no fire in the fuselage sections forward of the wings.

About 1646, firemen from the Cobb County Fire Dept. arrived and assisted the New Hope volunteers in extinguishing the fires. Ad­ditionally, volunteer firemen from the Hiram and Union volunteer fire departments assisted in the firefighting and rescue activities. The fires were extinguished in about 30 minutes.

Survival aspects. According to the CVR, at 1607:22 and shortly after the aircraft entered the heavy hail and rain, the aft flight atten­ dant announced on the cabin address system that the passengers should keep their seatbelts securely fastened. At 1608:38, the aft flight attendant made another announcement concerning the stowage of luggage and instructed the passengers about what to do in the event of an emergency landing.

Several minutes later, when the aft flight attendant was certain that both engines were inoperative, the flight attendants began 10 brief the passengers on emergency crash landing and evacuation procedures; they demonstrated how to open the exits, and how to assume the brace position on receipt of the flight crew-activated chime signal, or on command from the flight attendants. Additional­ ly, they instructed the passengers to remove sharp objects from clothing and stow the objects, to check that luggage was stowed securely, and to remove shoes to prevent damage to the evacuation slides.

After the briefings, the forward flight attendant opened the cockpit door to tell the flight crew that the passengers were prepared for an emergency landing. The first officer immediately told her to sit down, and she returned to the cabin. She noticed that the windshield was shattered. At 1616:28, the forward attendant called the aft atten­ dant on the interphone and told her about the situation in the cockpit and they discussed their preparations for an emergency lan­ ding and evacuation.

Shortly thereafter, the aft flight attendant saw trees outside the cabin window and she yelled to the passengers, “Grab your ankles!” The forward flight attendant repeated the command, and according to both attendants, the passengers responded as instructed. There were no signals from the flight crew that landing was imminent. Ac­cording to the flight attendants, they received no information from the flightcrew about what had happened after the aircraft entered the heavy hail, or how the flightcrew planned to land the aircraft.

After the aircraft stopped, both flight attendants freed themselves without assistance. The forward flight attendant was hanging upside down in her seat, restrained by her seatbelt (the seat had no shoulder harness). After releasing her seatbelt she fell onto debris inside what she thought was the galley area. When she was un­ able to open the main cabin door, she climbed through an opening in the fuselage and jumped to the ground. She ran to a nearby house to get help. There she saw some of the passengers.

The aft attendant recalled that the aircraft struck the ground about six times before it came to rest. A fireball erupted after the first or second impact and travelled rearward along the ceiling of the cabin. The fireball extended downward from the ceiling to the tops of the passenger seats. She saw passengers on fire before the aircraft stopped, but was unable to recall where these passengers were located. After prodding her hand with her apron because the release lever was hot, she released her seatbelt and stood up. A wall of fire was in front of her, and smoke caused her to cough repeatedly. After trying unsuccessfully to open the rear bulkhead door, she turn­ ed and moved forward because the flames had diminished, and walk­ ed out of the cabin onto the ground. She then began to pull passengers from the wreckage until an explosion forced her away. One passenger covered his head with a leather jacket and wedg­ ed a pillow between his face and the seatback in front of him just before impact. After the aircraft stopped, he removed the jacket; his head was burned by melted plastic which dripped from the ceiling. He moved forward and exited the aircraft through a hole in the fuselage.

Six of the surviving passengers were seated in the section of the cabin forward of the wing’s leading edge. Of these passengers, four were ejected from the aircraft, two of which were ejected with their seats. None of the four were burned although they sustained exten­ sive musco skeletal trauma. The remaining two passengers were seated in the row nearest the wings’ leading edge; they received ex­tensive second-degree burns. One of them said that fire and smoke were around him after the aircraft stopped, and one said that fire erupted during the impacts. Their seat and seatbelts remained intact. Five of the eight survivors who were seated in the portion of the cabin aft of the wings’ leading edge and just forward of the engine in­ takes said that fire erupted inside the cabin before the aircraft stopped. Almost all of these passengers said that smoke, fire, debris and bodies hampered their escape. The eight survivors said their seats remained intact. The passengers near the overwing exits opened the right exit but closed it because of fire. The eight passengers were burned severely; three sustained muscle-skeletal trauma.

Four of the five survivors in the aft section of the aircraft were ejected with their seats during the impacts. The condition of the fifth survivor’s seat could not be determined. All of these survivors were burned _seriously and three sustained muscle skeletal trauma.

The two survivors from the last row of seats reported that their seats remained intact and that fire was all around them when the aircraft stopped. Both passengers were seriously burned and one sustained rib fractures and lacerations.

Five hospitals were notified of the accident – the first was notified about 1620 and the last, about 1810. All of these hospitals im­plemented emergency plans and were prepared to care for the sur­ vivors. The first survivor arrived at JI Paulding Memorial Hospital in Dallas about 1630. An FAA-designated medical examiner and a nurse arrived at the accident scene about 1634; they were the first medically qualified persons on the scene. The medical examiner began triage and coordinated the transportation of survivors to hospitals.

The accident was partially survivable because some sections of the aircraft remained comparatively intact while others were demolished.

The forward fuselage section (from the leading edge of the wing forward) was completely destroyed by impact forces. The forward flight attendant survived because she was in an area of this section that shielded her from numerous impacts with trees and other ob­ jects. Most of the survivors from this section were ejected during its fragmentation and destruction but were seriously injured. Therefore, their survival was fortuitous rather than a consequence of design.

The accident was survivable for those passengers who were seated aft of the wings’ leading edges, except for those who were in­ juried too severely to escape unaided. A number of these passengers probably died in their seats from burns and smoke inhalation. For the most part, the survivors’ seats and seatbelts in this section remained intact, and about half the survivors were ejected from the wreckage. The ejected passengers were probably burned before they were ejected. The remaining survivors were not incapacitated and, therefore, were able to escape unaided although they were burned in the process. Consequently, certain areas of the aft cabin were sur­ vivable in spite of the fire, because these areas were not damaged as badly as the forward·part of the fuselage.

The feet of a number of the survivors were cut and some were also burned because they had no shoes for protection. In accordance with standard evacuation procedures, the flight attendants had brief­ ed the passengers to remove their shoes to prevent damage to evacuation slides. Because of the lack of information from the flight­ crew, the flight attendants had no way of knowing the circumstances associated with the landing and, therefore, had no reason to deviate from standard procedures.

Although the flightcrew was preoccupied with trying to restart the engines and with selecting suitable landing areas, the safety board concludes that a few words from the flightcrew to the flight atten­ dance about the type of landing expected might have enabled the attendants to better prepare the passengers. Had pillows and blankets been distributed and had shoes been worn, some of the passengers’ injuries probably would have been less severe and more passengers probably would have been able to escape from the wreckage.

Analysis and conclusions

Analysis. The pilots were certificated properly and were qualified for the flight. They had received the off-duty time required by regula­ tion. There was no direct evidence that medical or physiological lac­ tors might have affected the flightcrew’s performance.

The aircraft was certificated, equipped and maintained in accor­ dance with regulations and approved procedures. Before en­ countering the precipitation and hail which immediately preceded the loss of power from the engines, there was no evidence of a failure or a malfunction of the aircraft’s structure, powerplants or flight con­trols. Moreover, except for the possibility that the aircraft’s weather radar system may not have been functioning effectively, there was no evidence that any of the aircraft’s other systems had failed or malfunctioned.

From an evaluation of all the evidence, the safety board con­cludes that the causal factors related to this accident are associated with the severe weather conditions that Flight 242 encountered near Rome, Ga, the extent of the flightcrew’s knowledge of those con­ditions before the encounter and the information about those conditions provided to the flightcrew. After the severe weather con­ditions were encountered and thrust from the engines was complete­ ly and permanently lost, an accident most probably was inevitable.

Conclusions

Findings:

• Flight 242 penetrated a severe thunderstorm between 17,000 and 14,000ft near Rome, GA, while en route from Huntsville, Ala to Atlanta, GA.
• The ingestion of intense rain and hail into N133SU’s engines caused the rotational speed of both engines to decrease below the engine-driven electrical generator operating speeds and resulted in normal electrical power interruption for 36 seconds.
• Rotational speed on at least one engine increased sufficiently to restore its generator to operation and provide normal electrical power. •The rotation speed of one or both engines was probably in­creased by the advancement of the thrust lever(s).
• Shortly after the initial loss of rotational speed, both engines’ high-pressure compressors began to stall severely.
• The stalls probably resulted from a change in high-pressure compressor operating characteristics induced by thrust lever ad­vancement and ingestion of massive quantities of water.
• The severe compressor stalls produced an overpressure surge which deflected the compressor blades forward in the sixth stage of the low-pressure compressors; these blades clashed against the fifth­ stage stator vanes and broke pieces from the blades and vanes.
• Pieces of blades and stator vanes were then ingested into the high-pressure compressors and damaged them severely.
• Continued high thrust settings following the severe damage to the high-pressure compressors probably caused severe overheating in the turbine sections of both engines, and the engines ceased to function.
• Normal electrical power was again lost for 2 minutes 4 seconds until the APU-driven generator restored electrical power.
• After the engines failed, an accident was probably inevitable because Southern Airways’ flightcrews had not received, nor were they required to receive, training or information on emergency lan­ dings with all engines inoperative.
• Before departing Huntsville, the flightcrew of Flight 242 had no information on thunderstorms immediately west of the Rome VOR.
• While en route to the Rome VOR, the flightcrew received no information on the existence of the storms immediately west of the Rome VOR except for the indications displayed on their airborne radar system.
• Based on information from the airborne radar, the captain of Flight 242 initially decided that the storms just west of the Rome VOR were too severe to penetrate.
• Shortly after his initial assessment of the storm system, the captain decided to penetrate the storm area near the Rome VOR.
• Insufficient evidence precluded a positive determination regarding the possible effects of fatigue on the flightcrew’s reactions and decisions.
• The captain’s decision to penetrate the storm area was probably based on his interpretation of the weather radar display.
• At least 20 minutes before Flight 242 departed Huntsville, the NWS had identified by radar the precipitation in the Rome area as very strong and intense with indications of hail and cloud tops over 40,000ft.
• Southern Airways’ flight dispatch personnel did not monitor adequately the storm system that moved into the Rome area, and the information that the dispatch section provided to Flight 242 did not alert the flightcrew to the weather hazards along their route.
• The Atlanta Centre controllers had insufficient information about the storm system in the Rome area.
• Atlanta Centre’s surveillance radars were of limited value in displaying severe weather systems.
• The Atlanta Centre controllers acquired limited knowledge of the storm system in the Rome area from the surveillance radar.
• The Atlanta controllers provided no information to Flight 242 about the storm in the Rome area, and the flightcrew of Flight 242 did not request any information from them.
• The accident was partially survivable.
• The flight attendants acted commendably in initiating a com­prehensive emergency briefing of the passengers for their protection in preparation for a crash landing. This contributed to the number of survivors.

Probable cause

The National Transportation Safety Board determined that the probable cause of this accident was the total and unique loss of thrust from both engines while the aircraft was penetrating an area of severe thunderstorms. The loss of thrust was caused by the ingestion of massive amounts of water and hail which in combination with thrust lever movement induced severe stalling in and major damage to the engine compressors.

Major contributing factors included the failure of the company’s dispatching system to provide the flightcrew with up-to-date severe weather information pertaining to the aircraft’s intended route of flight, the captain’s reliance on airborne weather radar for penetra­tion of thunderstorm areas and lim1tat1ons m the Federal Av1at1on Ad­ ministration’s air traffic control system which precluded the timely dissemination of real-time hazardous weather information to the

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