On October 17, 2019, about 1740 Alaska daylight time, PenAir flight 3296, a Saab 2000, N686PA, overran the runway while landing at the Thomas Madsen Airport (PADU), Unalaska, Alaska. The airplane passed through the airport perimeter fence, crossed a road, and came to rest on shoreline rocks. Of the 42 passengers and crewmembers on board, 1 passenger was fatally injured, and several other passengers sustained serious or minor injuries. The airplane received substantial damage. The regularly scheduled domestic passenger flight was operating under the provisions of 14 Code of Federal Regulations Part 121 from Ted Stevens International Airport (KANC), Anchorage, Alaska, to PADU.
The landing gear manufacturer’s incorrect wiring of the wheel speed transducer harnesses on the left main landing gear during overhaul. The incorrect wiring caused the antiskid system not to function as intended, resulting in the failure of the left outboard tire and a significant loss of the airplane’s braking ability, which led to the runway overrun. Contributing to the accident were (1) Saab’s design of the wheel speed transducer wire harnesses, which did not consider and protect against human error during maintenance; (2) the Federal Aviation Administration’s lack of consideration of the runway safety area dimensions at Unalaska Airport during the authorization process that allowed the Saab 2000 to operate at the airport; and (3) the flight crewmembers’ inappropriate decision, due to their plan continuation bias, to land on a runway with a reported tailwind that exceeded the airplane manufacturer’s limit. The safety margin was further reduced because of PenAir’s failure to correctly apply its company-designated pilot-in-command airport qualification policy, which allowed the accident captain to operate at one of the most challenging airports in PenAir’s route system with limited experience at the airport and in the Saab 2000 airplane.
Saab 2000 · N686PA — 649,125 samples, 106 parameters, 15:16:44.7 to 17:40:31.0.
| Parameter | Max | at | Min | at | Final | at |
|---|---|---|---|---|---|---|
| Pressure altitude ft | 30,194.0 | 17:09:26.9 | 343.0 | 17:39:56.9 | 399.0 | 17:40:30.9 |
| Radio altitude ft | 2,596.0 | 15:25:23.4 | -4.0 | 15:18:14.4 | -3.0 | 17:40:30.4 |
| Pitch attitude deg | 10.4 | 15:24:09.2 | -20.0 | 17:40:29.2 | 1.1 | 17:40:30.9 |
| Roll attitude deg | 25.9 | 15:24:46.7 | -35.8 | 17:35:58.7 | -5.9 | 17:40:30.7 |
| Vertical acceleration g | 1.8 | 17:40:20.0 | -0.2 | 17:40:29.2 | 0.9 | 17:40:30.9 |
| Magnetic heading deg | 358.9 | 17:36:32.1 | 1.0 | 17:36:31.1 | 182.7 | 17:40:30.1 |
| Time | Event | Page |
|---|---|---|
| 1523 | Flight departed from ANC | 4 |
| N/A | Aircraft climbed to a pressure altitude of 30,000 ft and cruised on a southwesterly heading for about 1 hour and 26 minutes | 4 |
| N/A | Aircraft descended steadily for about 21 minutes | 4 |
| 1733:00 | Autopilot was disconnected and remained disconnected for remainder of flight | 4 |
| 1733:30 | Aircraft began a descent from 950 ft AGL | 4 |
| N/A | At 425 ft AGL the aircraft rolled 30 degrees left, rolling out at 172 ft AGL on a heading of 117 degrees, consistent with final approach to the runway | 4 |
| 1735:30 | Maneuvers consistent with a go around were performed | 4 |
| N/A | Following the go around, aircraft climbed to 1150 ft AGL and began to descend again while performing a 300 degree left turn | 4 |
| N/A | While descending through about 350 ft AGL, the aircraft rolled 30 degrees left, rolling out on the runway heading at about 100 ft AGL | 4 |
| N/A | As the aircraft rolled out from 100 ft to 50 ft AGL, a Sink Rate warning was recorded from the GPWS | 4 |
| N/A | Vertical speed recorded a peak of -1292 fpm during final descent | 4 |
| N/A | Aircraft roll angle oscillated +/- 5 degrees as it pitched up consistent with a landing flare | 4 |
| 1739:54 | Accelerations consistent with main gear touchdown occurred | 5 |
| 1739:55 | Nose gear touchdown | 5 |
| 1739:56 | 1 Hz Gear Weight on Wheels signal became true | 5 |
| N/A | Rate of deceleration increased over three seconds following main gear touchdown to a peak of -0.48 g; flaps retracted by 5 degrees and both propellers transitioned to beta mode | 5 |
| 1739:59 | Longitudinal deceleration changed from smooth to slightly oscillatory profile; Anti-Skid Inboard Fault Caution became active | 5 |
| 1740:03 | Engines transitioned from ground idle beta to max reverse power | 5 |
| 1740:10 | Longitudinal deceleration profile became smooth for 5.5 seconds; Anti-Skid Inboard Fault Caution transitioned to inactive | 5 |
| 1740:16 | Oscillations in longitudinal acceleration resumed and Anti-Skid Inboard Fault Caution reactivated | 5 |
| 1740:18 | Engine PLA began to increase from about 1 degree to about 35 degrees, consistent with idle power, over 3 seconds; engines and propellers transitioned to idle power and beta mode | 5 |
| 1740:19 | Changes in pitch, roll, and vertical and longitudinal accelerations were consistent with a departure of the runway surface | 5 |
| N/A | One second after runway departure, the weight on wheels and left main gear down and locked signals became false, consistent with damage to the left main gear | 5 |
| N/A | About one second after that the left engine gas generator speed dropped to 0%, consistent with damage to the left engine | 5 |
| 1740:31 | The recording stopped, consistent with a sudden power interruption to the recorder | 5 |
674 transcribed utterances from 15:36:30.0 to 17:41:36.9, 17 sources. Final entries:
| 17:41:28.6 | RDO-1 | and Dutch Harbor Radio we need uh - crash fire rescue...uh...crash fire rescue. |
| 17:41:29.4 | HOT | [sound similar to Master Warning] |
| 17:41:30.9 | HOT | [sound similar to Config Warning] Time and Intra-Aircraft Communication Time and Over-the-Air Communication Source Source |
| 17:41:34.4 | HOT | [sound similar to Master Warning] |
| 17:41:36.9 | HOT | [sound of switch actuating] |
Docket: data.ntsb.gov/Docket/?NTSBNumber=DCA20MA002. This brief is an analytical aid assembled from public records; it is not an investigative finding.