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: 314710

Reported Deaths: 7254
CountyCasesDeaths
DeSoto21646260
Hinds20369416
Harrison17949309
Rankin13643278
Jackson13450246
Madison10113217
Lee9986174
Jones8384163
Forrest7689152
Lauderdale7198240
Lowndes6403148
Lamar623686
Lafayette6203119
Washington5341134
Bolivar4802132
Oktibbeha462998
Panola4596107
Pearl River4519146
Marshall4450103
Warren4393121
Pontotoc420872
Monroe4115133
Union411176
Neshoba4031176
Lincoln3969110
Hancock379586
Leflore3498125
Sunflower336290
Tate334784
Pike3327105
Scott316274
Alcorn313368
Yazoo311770
Itawamba300577
Copiah297465
Coahoma295579
Simpson295388
Tippah288768
Adams286982
Prentiss280060
Marion269380
Leake268473
Wayne262841
Grenada261587
Covington259881
George248148
Newton246862
Winston227581
Tishomingo227067
Jasper221148
Attala214473
Chickasaw208057
Holmes189174
Clay185554
Stone182833
Tallahatchie178941
Clarke178080
Calhoun170932
Yalobusha164638
Smith162534
Walthall134245
Greene130633
Lawrence128724
Montgomery127142
Noxubee126734
Perry126338
Amite123142
Carroll121829
Webster114532
Jefferson Davis107133
Tunica105726
Claiborne102430
Benton100025
Humphreys96733
Kemper95828
Franklin83923
Quitman81116
Choctaw76418
Wilkinson67531
Jefferson65728
Sharkey50217
Issaquena1686
Unassigned00

Alabama Coronavirus Cases

Cases: 539829

Reported Deaths: 11038
CountyCasesDeaths
Jefferson798271529
Mobile41261809
Madison35132506
Tuscaloosa25915455
Shelby25294249
Montgomery24705593
Baldwin21392310
Lee15987172
Calhoun14569319
Morgan14422280
Etowah13918353
Marshall12275225
Houston10641282
Elmore10147206
Limestone10065151
St. Clair9946245
Cullman9761194
Lauderdale9457243
DeKalb8865188
Talladega8339176
Walker7260278
Autauga7001108
Jackson6836112
Blount6771139
Colbert6320135
Coffee5578118
Dale4876113
Russell445138
Chilton4369113
Franklin426282
Covington4138118
Tallapoosa4044153
Escambia394777
Chambers3590123
Dallas3568153
Clarke351461
Marion3137101
Pike311977
Lawrence302698
Winston275773
Bibb264564
Geneva254078
Marengo249665
Pickens234862
Barbour232056
Hale223978
Butler219069
Fayette212662
Henry189643
Cherokee184645
Randolph182442
Monroe178141
Washington167739
Macon161150
Clay157157
Crenshaw153557
Cleburne149641
Lamar143236
Lowndes140553
Wilcox127430
Bullock123242
Conecuh110829
Coosa109228
Perry107826
Sumter104932
Greene92634
Choctaw61024
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