Southwest Airlines Flight 1380


Southwest Airlines Flight 1380 was a Boeing 737-7H4 that experienced a failure in the left CFM56-7B engine after departing from New York–LaGuardia Airport en route to Dallas Love Field on April 17, 2018. The engine cowl was broken in the failure and cowl fragments damaged the fuselage, causing rapid depressurization of the aircraft after damaging a cabin window. Other fragments caused damage to the wing. The crew conducted an emergency descent and diverted to Philadelphia International Airport. One passenger was partially ejected from the aircraft and later died. Eight other passengers received minor injuries. The aircraft was substantially damaged.
This accident was identical to the accident suffered 30 months earlier by Southwest Airlines Flight 3472 flying the same aircraft type, with the same engine type. After that accident, the engine manufacturer, CMF, issued a service directive calling for ultrasonic inspections of the turbine fan blades, with certain serial numbers, service cycles, or service time. Southwest did not do this as this engine was not within the parameters specified by the directive.
It was the first fatal airline accident involving a U.S. passenger carrier since the crash of Colgan Air Flight 3407 in February 2009, and the first aircraft accident involving Southwest Airlines that resulted in the death of a passenger.

Background

Flight 1380 was a regularly scheduled passenger flight from New York-LaGuardia Airport to Dallas Love Field. The aircraft was a Boeing 737-7H4 with the registration N772SW, in service with Southwest Airlines since its manufacture in 2000. It was powered by CFM56-7B engines.
Tammie Jo Shults, a former United States Navy fighter pilot, was the captain of the flight; while Darren Ellisor, a former United States Air Force pilot with experience in the Boeing E-3 Sentry, was the first officer. Captain Shults had been with Southwest Airlines since 1994 and had logged a total 11,715 flight hours, including 10,513 hours on the Boeing 737. First officer Ellisor had been with the airline since 2008 and had 9,508 flight hours, with 6,927 of them on the Boeing 737. There were 144 passengers and a total of five crew members on board.

Accident

At 11:03 Eastern Daylight Time, the aircraft was at about flight level 320 and climbing when the left engine failed. As a result, most of the engine inlet and parts of the cowling broke off. Fragments from the inlet and cowling struck the wing and fuselage and broke a window in the passenger compartment, which caused rapid decompression of the aircraft. The flight crew conducted an emergency descent of the aircraft and diverted it to Philadelphia International Airport. One passenger sitting next to the broken window suffered fatal injuries, and eight passengers sustained minor injuries. The aircraft sustained substantial damage.
The flight crew stated that the departure and climb from LaGuardia were normal with no indications of any problems; the first officer was flying and the captain was monitoring. They reported that the aircraft yawed and set off several cockpit emergency alarms; a "gray puff of smoke" appeared and the aircraft's cabin suddenly lost air pressure. The flight crew donned their emergency oxygen masks, and the first officer began the emergency descent. The flight data recorder showed that the left engine's performance parameters all dropped simultaneously, vibration became severe, and, within five seconds, the cabin altitude alert activated. The data recorder also showed that the aircraft rolled left by about 40 degrees before the flight crew was able to counter the roll. The flight crew reported that the aircraft was very difficult to control throughout the remainder of the flight because of the extensive damage. The captain took over flying the plane and the first officer carried out the emergency checklist. The captain asked the air traffic controller for a course diversion. She initially requested a course to the nearest airport, but then decided that the airport in Philadelphia was best equipped for this aircraft's emergency. The controller quickly provided vectors to the Philadelphia airport. The flight crew reported initial communications difficulties because of the loud noises, distraction, and wearing oxygen masks, but, as the aircraft descended, communications improved. The captain initially planned on a long final approach to make sure the crew completed all the emergency checklists. However, upon learning of the passengers' injuries, she decided to speed up the approach and expedite landing.
Three flight attendants were assigned to the flight, and another Southwest Airlines employee was a passenger. All four reported that they heard a loud sound and felt severe vibration. The oxygen masks automatically deployed in the cabin. The flight attendants retrieved portable oxygen bottles and began moving through the cabin to assist passengers with their oxygen masks. As they moved toward the mid-cabin, they found a passenger in row 14 sucked part way out the broken window; with the help of two passengers, flight attendants pulled the victim inside the aircraft, and other passengers performed emergency cardiopulmonary resuscitation. The passenger died after being admitted to a local hospital for treatment from the injuries she suffered in the aircraft.

Investigation

Initial investigation

The participants in the investigation included the National Transportation Safety Board, the United States Federal Aviation Administration, Boeing, Southwest Airlines, GE Aviation, the Aircraft Mechanics Fraternal Association, the Southwest Airlines Pilots’ Association, the Transport Workers Union of America, and UTC Aerospace Systems. Because the manufacturer of the failed engine – CFM International – is a US-French joint venture, the French Bureau of Enquiry and Analysis for Civil Aviation Safety also contributed investigators. Technical teams from CFM assisted with the investigation as well. The NTSB expected the investigation to take 12 to 15 months.
NTSB investigators analyzed a recording of the air traffic radar plots and observed that the radar had shown debris falling from the aircraft, and used wind data to predict where ground searchers could find it. Parts from the engine's nacelle were found in the predicted area at several locations near the town of Bernville, Berks County, Pennsylvania, some northwest of Philadelphia.
On April 20, 2018, CFM issued Service Bulletin 72-1033, applicable to the CFM56-7B-series engine,
and on the same day the FAA issued Emergency Airworthiness Directive 2018-09-51
based on it. The CFM service bulletin recommended ultrasonic inspections of all fan blades on engines that have accumulated 20,000 engine cycles and subsequently at intervals not to exceed 3,000 engine cycles. The EAD required CFM56-7B engine fleet fan blade inspections for engines with 30,000 or greater cycles, within 20 days of issuance, per the instructions provided in the service bulletin, and if any crack indications were found the affected fan blade must be removed from service before further flight. This directive was issued as a one time inspection requirement. On the same day, European Aviation Safety Agency also issued EAD 2018-0093E that required the same ultrasonic fan blade inspections to be performed. The engine manufacturer estimated the new directive affected 352 engines in the US and 681 engines worldwide.
On April 23, 2018, Southwest Airlines announced that it was voluntarily going beyond the FAA EAD requirement and performing ultrasonic inspections on all CFM engines in its fleet, including two each on approximately 700 Boeing 737-700 and 737-800 aircraft.
On April 30, 2018, the aircraft involved in the accident was released by the NTSB, and was flown by Southwest Airlines to a service facility performing major services on Boeing aircraft at Paine Field in Everett, Washington for repairs.
On May 2, 2018, the FAA issued a follow up Airworthiness Directive, 2018-09-10, which expanded the inspections on CFM56-7B engines beyond the original EAD 2018-09-51. The new AD required inspections of engines with lower cycles, and introduced repeat inspection requirements as well. Effective with the issuance of this AD, operators are required to perform detailed inspections on each fan blade before the fan blade accumulates 20,000 cycles since new, or within 113 days, whichever occurs later. If cycles since new on a fan blade is unknown, then the airline is to perform an initial inspection within 113 days from the effective date of this AD. Thereafter, repeat this inspection no later than 3,000 cycles since the last inspection. If any unserviceable fan blade is found, it must be removed from service before further flight. The FAA estimates this AD affects 3,716 engines installed on aircraft of U.S. registry at an estimated cost of 8,585 per blade replacement.
On June 7, 2018, the aircraft involved in the accident was flown from a service facility performing major services on Boeing aircraft at Paine Field in Everett, Washington to Southern California Logistics Airport in Victorville, California for storage. As of April 2020, the aircraft has not been flown.

Preliminary findings

On May 3, 2018, the NTSB released an investigative update with preliminary findings:
The NTSB held an investigative hearing on November 14, 2018. At the hearing, FAA Transport Standards Branch representative Victor Wicklund stated that the production inlets were not required to be subjected to certification testing, but if they had been and had failed, as was the case in this accident, that it would constitute a certification failure. He indicated that the cowling may require design changes.
The NTSB held a second investigative hearing on November 19, 2019. The NTSB also issued seven safety recommendations to the FAA.

Final report

On November 19, 2019, following the aforementioned hearing. The NTSB released the final report on the accident. the probable cause reads:
The National Transportation Safety Board determines that the probable cause of this accident was a low-cycle fatigue crack in the dovetail of fan blade No. 13, which resulted in the fan blade separating in flight and impacting the engine fan case at a location that was critical to the structural integrity and performance of the fan cowl structure. This impact led to the in-flight separation of fan cowl components, including the inboard fan cowl aft latch keeper, which struck the fuselage near a cabin window and caused the window to depart from the airplane, the cabin to rapidly depressurize, and the passenger fatality.

Reactions

On the day of the incident, Elaine Chao, the United States Secretary of Transportation, made a statement to "commend the pilots who safely landed the aircraft, and the crew and fellow passengers who provided support and care for the injured, preventing what could have been far worse." Shortly thereafter, Martha McSally, then a member of the United States House of Representatives from Arizona, introduced a resolution in Congress commending Captain Shults.
On May 1, 2018, US President Donald Trump welcomed the crew members and selected passengers in a ceremony at the Oval Office of the White House, thanking them all for their heroism.

Aftermath

Southwest Airlines gave each passenger $5,000 and a $1,000 voucher for future travel with the airline. Southwest Airlines bookings fell following the accident, resulting in a projected decline in revenue for the airline for the second quarter of 2018. Following the accident, Lilia Chavez, a passenger on board the flight, filed a lawsuit against Southwest Airlines, claiming that she suffers from posttraumatic stress disorder since the accident. Her lawsuit was later settled.
Captain Shults published a book about the incident, titled "Nerves of Steel". The book was released on October 8, 2019 in the United States.
The aircraft, N772SW, a Boeing 737-7H4 was subsequently flown to Boeing in Everett, WA on April 30, 2018 for repairs. The plane was moved into storage at Victorville, CA on June 7, 2018. The aircraft remains there and has not made a scheduled revenue flight since.