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SWA3472 Engine Blew KPNS
Southwest 3472 suffers an uncontained engine failure and rapid decompression, diverting safely to Pensacola.
Summary
On August 27, 2016, Southwest Airlines Flight 3472 experienced a catastrophic uncontained engine failure of its left CFM56-7B engine while en route from New Orleans to Orlando. The failure caused debris to puncture the fuselage, leading to a rapid loss of cabin pressure. The crew executed an emergency descent and landed safely at Pensacola International Airport with no injuries among the 99 souls on board.
Analysis
This recording captures a textbook example of professional emergency management by both the flight crew and air traffic control. The incident began when a fan blade in the left engine separated due to metal fatigue, causing the engine to disintegrate. Because it was an "uncontained" failure, the engine cowling did not trap all the debris; fragments struck the aircraft's fuselage, leading to the "uncontrollable" cabin altitude mentioned by the pilot.
A notable aspect of this transcript is the inclusion of the pilot running through the Quick Reference Handbook (QRH) checklists. Listeners can hear the crew systematically addressing the APU start, bus transfers, and the pressurization mode selector. This provides a rare, real-time look at how pilots manage multiple failures—engine loss combined with decompression—simultaneously. The pilot’s voice remains remarkably calm despite the severity of the situation.
The coordination between Approach, Tower, and Rescue units highlights the "behind-the-scenes" work during an emergency. The controllers proactively offer different runways (switching from Runway 8 to 17) and navigation aids (the ILS approach) to reduce the pilot's workload. The transition of "Incident Command" to the City Battalion on the ground shows the standard protocol for preparing for a potential crash or fire upon landing.
Technically, this event was significant for the aviation industry. The NTSB investigation led to new mandates for ultrasonic inspections of fan blades on CFM56 engines. It is often cited as a precursor to the fatal Southwest Flight 1380 incident in 2018, which involved a similar engine failure. The successful outcome here is attributed to the crew's adherence to training and the prompt response of Pensacola ATC.
Original ATC Communication
Plain English Translation
SWA3472
Pensacola Approach, Southwest 3472.
SWA3472
Pensacola air traffic control, this is Southwest flight 3472.
ATC
Southwest 3472, Pensacola Approach. Pensacola altimeter 30.08. Expect visual approach, runway 8.
ATC
Southwest 3472, this is Pensacola. The local air pressure for your altitude gauge is 30.08. Plan on a landing by sight on runway 8.
SWA3472
30.08, and you said expect runway 8?
SWA3472
30.08 on the pressure, and did you say to expect runway 8?
ATC
Visual approach, runway 8. Southwest 3472, was it the right or left engine? Also, I need fuel and souls on board if you can give that to me.
ATC
Yes, land by sight on runway 8. Southwest 3472, was it the right or left engine that failed? Also, I need to know how much fuel you have and the total number of people on board when you can.
SWA3472
Okay, it's the left engine. Souls on board are 99, and fuel is two and a half hours of fuel on board.
SWA3472
Okay, it’s the left engine. We have 99 people on board, and we have enough fuel to stay airborne for two and a half hours.
ATC
Southwest 3472, Roger. Descend at pilot's discretion, maintain 9,000.
ATC
Southwest 3472, understood. Start your descent whenever you're ready and level off at 9,000 feet.
SWA3472
Pilot's discretion to 9,000, Southwest 3472. APU start. APU generator is on. Bus transfer is on. Balance fuel as needed. Transponder to TA—I did that. Isolation valve—after the fire has been extinguished, it's at Auto. Landing nearest suitable airport. Do not use fuel FMC prediction.
SWA3472
Descending to 9,000 when ready, Southwest 3472. Starting the backup power unit. Backup generator is on. Electrical power is transferred. Balancing the fuel. Setting the radar beacon to alert—done. The air valve is set to automatic now that the fire is out. We're landing at the nearest suitable airport. Don't trust the computer's fuel estimates.
ATC
Giant 55 Charlie, Pensacola Approach. Roger, for now, heading 280.
ATC
Giant 55 Charlie, Pensacola. Copy that, for now, fly a heading of 280 degrees.
SWA3472
Communications are established. Pressurization mode selector to manual. Outflow valve switch, hold in close position until valve is closed. It is closed. Cabin altitude is uncontrollable. Passenger signs on. Okay, it's closed. Cabin altitude is uncontrollable. Passenger signs on.
SWA3472
Radio contact is solid. Setting the cabin pressure to manual. Holding the air vent switch closed until the valve shuts. It’s closed. We can't control the cabin air pressure. Turn the passenger signs on. Okay, it's shut, but the cabin pressure is still out of control. Passenger signs on.
ATC
Southwest 3472, descend at pilot's discretion, maintain 4,000.
ATC
Southwest 3472, descend whenever you need to and level off at 4,000 feet.
SWA3472
Southwest 3472.
SWA3472
Southwest 3472, copy that.
ATC
Southwest 3472, say altitude.
ATC
Southwest 3472, what is your current altitude?
SWA3472
We’re out of 13.3 right now for Southwest 3472.
SWA3472
We are passing through 13,300 feet right now, Southwest 3472.
ATC
Southwest 3472, Roger. Southwest 3472, Pensacola weather: runway 8, wind 060 at 6, visibility 10, 4,000 scattered, altimeter 30.00. You can expect runway 8.
ATC
Southwest 3472, understood. Here is the Pensacola weather: for runway 8, wind is from the northeast at 6 knots, visibility is 10 miles, a few clouds at 4,000 feet, and the pressure setting is 30.00. Plan for runway 8.
SWA3472
We got all that, 30.00. If you could give me a vector out to the east a little bit and then bring us back in, we’d appreciate it.
SWA3472
We’ve got all that, pressure 30.00. If you could give us directions to fly east for a bit to give us some room before bringing us back in to land, we’d appreciate it.
ATC
Southwest 3472, for now, heading 040.
ATC
Southwest 3472, for now, turn to a northeast heading of zero-four-zero.
SWA3472
040, Southwest 3472.
SWA3472
Heading zero-four-zero, Southwest 3472.
ATC
Southwest 3472, say altitude, and when able, heading 040.
ATC
Southwest 3472, tell me your current altitude, and when you're able, turn to heading zero-four-zero.
SWA3472
All right, we’re coming left, 040, and we’re out of 10 now for 4,000, Southwest 3472.
SWA3472
All right, we’re turning left to zero-four-zero, and we’re passing through ten thousand feet descending to four thousand, Southwest 3472.
ATC
Southwest 3472, Roger. Descend and maintain 3,000, pilot's discretion.
ATC
Southwest 3472, understood. Drop down and stay at three thousand feet, whenever you're ready to start the descent.
SWA3472
Discretion to 3,000, Southwest 3472.
SWA3472
Descending to three thousand whenever we're ready, Southwest 3472.
ATC
Southwest 3472, fly heading 360. Say altitude now.
ATC
Southwest 3472, turn due north to heading three-six-zero. Tell me your altitude now.
SWA3472
Out of 3,400 for 3,000.
SWA3472
Passing through thirty-four hundred feet on our way down to three thousand.
ATC
Southwest 3472, Roger. Southwest 3472, if you prefer runway 17, I can work that out for you. Winds are 070 at 5.
ATC
Southwest 3472, copy that. If you'd rather land on the south-facing runway, I can arrange that for you. The wind is light at five knots coming from the east.
SWA3472
We'll take that.
SWA3472
We'll take that runway.
ATC
Southwest 3472, you can expect that. Turn right, heading 060.
ATC
Southwest 3472, you’ve got it. Turn right to heading zero-six-zero.
SWA3472
Right heading 060, Southwest 3472.
SWA3472
Right turn to zero-six-zero, Southwest 3472.
ATC
Southwest 3472, turn right, heading 070.
ATC
Southwest 3472, turn right a bit more to heading zero-seven-zero.
SWA3472
070, Southwest 3472.
SWA3472
Heading zero-seven-zero, Southwest 3472.
ATC
Southwest 3472, on your roll turn, the field will be at about 1 to 2 o'clock and nine miles. Southwest 3472, descend and maintain 1,700. Southwest 3472, if it makes you feel more comfortable, I can put you on the ILS for 17.
ATC
Southwest 3472, as you roll out of your turn, the airport will be just off to your right at the one or two o'clock position, nine miles away. Drop down and stay at seventeen hundred feet. If it makes things easier, I can guide you onto the automated instrument landing system for that south runway.
SWA3472
Southwest 3472, we'll take that.
SWA3472
Southwest 3472, we’ll go with that plan.
ATC
Southwest 3472, you can expect that. Fly heading 060.
ATC
Southwest 3472, you can expect that. Fly a heading of 060 degrees.
SWA3472
060 now, Southwest 3472.
SWA3472
Turning to 060 now, Southwest 3472.
ATC
Southwest 3472, turn right, heading 100.
ATC
Southwest 3472, turn right to heading 100.
SWA3472
100, Southwest 3472.
SWA3472
Heading 100, Southwest 3472.
ATC
Southwest 3472, turn right, heading 120. Southwest 3472, it's five miles from Brent. Turn right, heading 140. Maintain 1,700 until established on the localizer. Cleared ILS runway 17 approach.
ATC
Southwest 3472, turn right to heading 120. Southwest 3472, you're five miles from the Brent checkpoint. Turn right to heading 140. Stay at 1,700 feet until you've locked onto the runway's guidance beam. You are cleared for the instrument landing approach to runway 17.
SWA3472
140 on the heading, down to 1,700. Cleared the ILS to 17, Southwest 3472.
SWA3472
Turning to 140 and heading down to 1,700 feet. We're cleared for the instrument landing on runway 17, Southwest 3472.
ATC
Southwest 3472, altimeter 30.00. The field, on your roll turn, will be at 12 o'clock and about six miles.
ATC
Southwest 3472, the local air pressure for your altitude gauge is 30.00. As you come out of your turn, the airport will be directly in front of you at 12 o'clock, about six miles away.
SWA3472
3472.
SWA3472
3472, copy that.
ATC
Southwest 3472, contact Tower, 119.9.
ATC
Southwest 3472, switch over and talk to the Tower controllers on frequency 119.9.
SWA3472
119.9, Southwest 3472.
SWA3472
119.9, Southwest 3472.
RESCUE
Rescue 1 is coming from the west. We don't have which runway they've requested yet. I would expect runway 8 for now.
RESCUE
Rescue 1 is responding from the west. We don't know which runway the pilots have asked for yet, but I’m expecting them to use runway 8 for now.
TOWER
Roger. Could you update me so I can move to a standby position?
TOWER
Understood. Could you keep me posted so I can move into a standby position to help?
RESCUE
Rescue 110, Roger. Will co. Rescue 112, Rescue 110, proceed into the movement area. Hold short of the runways, please.
RESCUE
Rescue 110, Roger, will do. Rescue 112, this is Rescue 110, go ahead and drive out onto the active airfield. Just make sure to stop before you reach the runways.
OTHER PILOT
Pensacola Tower, Skyhawk 600, request taxi to the run-up area.
OTHER PILOT
Pensacola Tower, this is Skyhawk 600, requesting permission to taxi over to the engine-testing area.
TOWER
Skyhawk 600, hold your position in the run-up area. 10 miles to the west is a Boeing 737 in an emergency status. They look like they're coming into runway 8 for now, so let me just have you please hold your position.
TOWER
Skyhawk 600, stay right where you are in the engine-check area. There's a Boeing 737 in an emergency 10 miles to the west. It looks like they’re heading for runway 8 for now, so please just stay put.
RESCUE
Rescue 112, are you getting the update that the aircraft is now 10 miles to the west, landing runway 8? Rescue 110, you can proceed onto runway 8 to the approach end. Rescue 110, the aircraft has now requested to land 17. He's now heading north to runway 17.
RESCUE
Rescue 112, did you get the update that the plane is now 10 miles west and landing on runway 8? Rescue 110, you can drive onto the start of runway 8. Wait, Rescue 110, the pilot just asked for runway 17 instead. He’s turning north toward runway 17 now.
BATTALION
Pensacola Ground, City Battalion 1. We'll be assuming incident command at this point.
BATTALION
Pensacola Ground, this is City Battalion 1. We’re taking over as the lead commanders for this emergency response.
RESCUE
Rescue 110, you can continue into the movement area, just hold short of the runway.
RESCUE
Rescue 110, you’re clear to drive into the active taxi area, just stop right before you reach the runway.
BATTALION
City Battalion 1, I just want to make sure you're aware the emergency aircraft is now going to be landing runway 17.
BATTALION
City Battalion 1, I want to make sure you know the plane in trouble is now going to be landing on runway 17.
TOWER
Southwest 3472, Pensacola Tower. Runway 17, cleared to land. Wind 070 at 6.
TOWER
Southwest 3472, this is the tower. You are all clear to land on runway 17. The wind is coming from the east at 6 knots.
SWA3472
Cleared to land 17, Southwest 3472. And ma'am, as we are an emergency aircraft, we would like to request the emergency vehicles.
SWA3472
Clear to land on 17, Southwest 3472. And ma'am, since we are an emergency aircraft, we’d like the fire and rescue trucks to be waiting for us.
TOWER
Southwest 3472, emergency vehicles are standing by.
TOWER
Southwest 3472, the emergency crews are already in position and standing by.
SWA3472
Thank you.
SWA3472
Thank you.
TOWER
Southwest 3472, say fuel on board.
TOWER
Southwest 3472, tell me how much fuel you have left on board.
SWA3472
Two and a half hours.
SWA3472
We have two and a half hours of fuel.
RESCUE
Rescue 110, that aircraft has two and a half hours of fuel remaining. You can proceed onto runway 17 to follow the aircraft.
RESCUE
Rescue 110, that plane has two and a half hours of fuel remaining. You can drive onto runway 17 to follow behind the plane as it lands.
TOWER
Southwest 3472, turn right on the end. The rescue vehicles will follow you.
TOWER
Southwest 3472, turn right at the very end of the runway. The rescue trucks are going to follow you in.
SWA3472
Right on the end. Rescue vehicles will follow. Thanks for your help.
SWA3472
Right at the end. The rescue trucks will follow us. Thanks for all your help.
TOWER
No problem, sir. Contact Ground Control. Have a good one.
TOWER
No problem at all, sir. Switch over to the ground controllers now. Take care.
SWA3472
Pensacola Ground, Southwest 3472, clear of runway 17.
SWA3472
Pensacola Ground, this is Southwest 3472. We’ve pulled off runway 17 and are clear of the landing area.
GROUND
Southwest 3472, Pensacola Ground. Taxi to the terminal via Alpha, Alpha 7. Cross runway 8 at Alpha.
GROUND
Southwest 3472, Pensacola Ground. Drive to the terminal using taxiway Alpha and Alpha 7. You are cleared to cross over runway 8 at the Alpha intersection.
SWA3472
Alpha, Alpha 7, and cross runway 8 at Alpha, Southwest 3472. Hey, as we go by, how does that motor look?
SWA3472
Alpha, Alpha 7, and cross runway 8 at Alpha, Southwest 3472. Hey, as we taxi past you, can you see that engine? How does it look from the tower?
GROUND
Southwest 3472, could you tell me your departure point and your destination?
GROUND
Southwest 3472, could you tell me where you originally took off from and where you were supposed to be going?
SWA3472
We left New Orleans, destination was Orlando.
SWA3472
We took off from New Orleans, and our destination was Orlando.
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