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Southwest emergency landing puts focus on engine safety

Just look at the left engine of Southwest Flight 1380, and it's obvious that something terrible befell that machine....

Posted: Apr 19, 2018 11:00 AM
Updated: Apr 19, 2018 11:01 AM

Just look at the left engine of Southwest Flight 1380, and it's obvious that something terrible befell that machine.

Whatever happened inside that complicated system of fuel and fire and whirling components, it resulted in the decompression of the cabin at about 32,000 feet and, later, the death of a passenger after she nearly flew out a window.

When pilots Tuesday safely diverted the Boeing 737-700 -- with 149 passengers and crew members on board -- to Philadelphia from its New York-to-Dallas route, the metal surrounding the engine was in tatters.

As federal investigators begin to piece together what happened, the flying public undoubtedly is asking: What about the thousands of other jet engines in service right now?

The Southwest jet engine showed evidence of "metal fatigue," National Transportation Safety Board Chairman Robert Sumwalt told CNN's "New Day" on Wednesday. "What we want to find out is why was this not detected ahead of time."

"This was an internal metal fatigue area," Sumwalt continued. "So careful (visual) maintenance inspection from outside the fan blade would not have detected it, more than likely."

This has happened before

In 2016, the same airline and the same type of jet experienced an engine failure en route from New Orleans to Orlando, forcing the plane to land in Pensacola, Florida.

Engine debris damaged the jet's fuselage, wing and tail, according to the NTSB. The passenger compartment wasn't penetrated, but the cabin did decompress. Part of a fan blade had separated from the engine, and inspectors found evidence of a crack in the fan blade, which they said was consistent with metal fatigue.

"Nobody got injured, but it was hauntingly parallel to what happened yesterday," CNN aviation analyst Miles O'Brien said.

Manufacturers regularly inspect engines for hidden cracks using X-ray machines or ultrasound devices -- the same kind of technology doctors use to check the health of expectant mothers.

"The engines are the most closely monitored piece on the airplane," said John Goglia, a former NTSB board member. "Every engine manufacturer and airline monitors them very, very closely."

But engine maintenance and inspection protocols vary by airline, Goglia said, adding that airlines, in consultation with engine manufacturers, must get their maintenance protocols approved by the Federal Aviation Administration.

Southwest Airlines said in an email Wednesday that workers did a visual inspection of the engine that failed. An ultrasonic inspection of engine was scheduled to take place this December.

CFM International, which made the engine that apparently failed, issued a service bulletin in June 2017, recommending that operators who had planes with 15,000 or more cycles on their engines since their last inspection should perform ultrasonic tests on the fan blades. An engine cycle lasts from when an engine starts until it shuts down.

The FAA followed with a proposed rule in August calling for inspection of certain fan blades on CFM56 turbofan engines. Southwest in October 2017 sent a letter to the FAA saying it needed 18 months to complete the inspections.

The FAA's proposed rule was never put into effect, said Mary Schiavo, a former inspector general with the Department of Transportation, which oversees the FAA, and it's unclear whether Southwest ever began the inspections based on the FAA proposal. CNN has reached out to Southwest and the FAA for clarification.

Sumwalt said Southwest CEO Gary Kelly told him on Tuesday night that "Southwest will begin an aggressive ultrasonic inspection campaign for their entire fleet." That covers more than 700 737s, including more than 500 737-700s.

"The accelerated inspections are being performed out of an abundance of caution and are expected to be completed over the next 30 days," according to a statement on Southwest's website.

Schiavo called for a "surgical grounding" -- "a very strategic grounding of certain engines on certain planes to get this testing done immediately."

CFM did not respond to CNN's request for comment. In a statement on its website, the company said: "The CFM56-7B engine powering this aircraft has compiled an outstanding safety and reliability record since entering revenues service in 1997 while powering more than 6,700 aircraft worldwide. The engine family has accumulated more than 350 million flight hours as one of the most reliable and popular jet engines in airline history."

Engine problems in a worst-case wreck

One of the most infamous cases of engine failure -- a worst-case scenario -- involved United Flight 232, a triple-engine jetliner carrying 11 crew and 285 passengers from Denver to Chicago in 1989.

A fan disk came apart inside the engine, cutting through the plane's hydraulic system and disabling all flight controls. The crew was forced to use its remaining two engines to steer the plane to an emergency crash landing at the airport in Sioux City, Iowa. The fiery crash killed 111 people.

After using volunteers to comb the surrounding countryside, inspectors found the fan disk buried in a field. It showed a half-inch fatigue crack. Further investigation showed that the crack existed at the time of the engine's previous inspection but wasn't detected. The NTSB said the probable cause of the wreck was "inadequate consideration" of "human factors" and "limitations in the inspection and quality control procedures used by United Airlines."

As for Tuesday's incident, "The NTSB and the FAA are going to be looking very closely at the sequence of events that led up to this accident," Gogila said. "It's going to take some time to determine what happened, unless it's really obvious. There have been occasions when the NTSB and the FAA have moved almost instantaneously, but that's pretty rare."

The NTSB is focusing on preventive measures, Sumwalt said. "We want to look at procedures to discover this before it is catastrophic."

Mississippi Coronavirus Cases

Data is updated nightly.

Cases: 473413

Reported Deaths: 9214
CountyCasesDeaths
Harrison32339474
Hinds30703575
DeSoto29814346
Jackson23263336
Rankin21111358
Lee14600217
Madison14043265
Jones13165218
Forrest12953233
Lauderdale11418297
Lowndes10249175
Lamar10048128
Pearl River8737209
Lafayette8078136
Hancock7324111
Washington6837147
Oktibbeha6820118
Neshoba6404201
Monroe6372158
Warren6326161
Pontotoc610393
Panola6071124
Bolivar6016143
Marshall5972118
Union564086
Pike5491133
Lincoln5232130
Alcorn520888
George457868
Scott451993
Leflore4401140
Prentiss437276
Itawamba436198
Tippah436180
Simpson4268111
Copiah425586
Wayne424863
Tate4234100
Adams4219114
Yazoo415886
Sunflower4088104
Covington407391
Marion4032100
Leake393185
Coahoma388198
Newton364474
Grenada3517101
Stone345657
Tishomingo324888
Attala321185
Jasper310262
Winston300391
Clay288273
Chickasaw282164
Clarke277487
Calhoun259739
Holmes259485
Smith243947
Yalobusha216747
Tallahatchie215649
Walthall205557
Greene204045
Lawrence203831
Perry196453
Amite193751
Webster191941
Noxubee174538
Montgomery169853
Jefferson Davis165541
Carroll159937
Tunica148434
Benton139433
Kemper137439
Claiborne125634
Choctaw124925
Humphreys123337
Franklin115227
Quitman101825
Wilkinson99835
Jefferson86632
Sharkey62120
Issaquena1916
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Alabama Coronavirus Cases

Cases: 768301

Reported Deaths: 13209
CountyCasesDeaths
Jefferson1093481727
Mobile699891179
Madison48418589
Baldwin35707452
Shelby35193291
Tuscaloosa33029512
Montgomery32582664
Lee21908204
Calhoun20140377
Morgan19351318
Etowah18583433
Marshall17272259
Houston16139353
St. Clair14956276
Limestone14129180
Cullman14069235
Elmore14010245
Lauderdale13128272
Talladega12399215
DeKalb11890229
Walker10231312
Autauga9493127
Blount9418149
Jackson9115136
Coffee8646161
Colbert8324169
Dale8284159
Escambia6456106
Tallapoosa6394168
Covington6313157
Chilton6243133
Russell591654
Franklin563597
Chambers5240132
Marion4628115
Dallas4626178
Clarke451471
Pike450091
Geneva4252106
Winston407987
Lawrence4046102
Bibb396177
Barbour338968
Marengo320981
Monroe311547
Butler309783
Pickens298769
Randolph294055
Henry293856
Hale286081
Cherokee279850
Fayette272271
Washington243545
Crenshaw232265
Clay221561
Macon214454
Cleburne209748
Lamar187839
Conecuh177139
Lowndes169056
Coosa163631
Wilcox154335
Bullock147142
Perry134235
Sumter123335
Greene119241
Choctaw72325
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