Narrative:United Express Flight 2415 took off from Seattle for a flight to Pasco via Yakima. While flying into Yakima, the flight encountered icing conditions. After landing, the first officer (together with a deadheading pilot) knocked ice of the wings. The NPA station agent at Yakima asked the captain if he wanted to deice the aircraft, or just the tail plane, since both pilots just removed the ice from the wings. The captain declined both offers.
The aircraft took off again at 22.03 using runway 27. Since Pasco tower was closing at 22:30, Seattle Center cleared the flight for an ILS runway 21R approach. At 22:30 the aircraft was observed descending fast from a higher than normal altitude. The aircraft suddenly nosed over and crashed short of the runway.
Probable Cause:
PROBABLE CAUSE: "The flight crew's decision to continue an unstabilized instrument landing system approach that led to a stall, most likely of the horizontal stabilizer, and loss of control at low altitude. Contributing to the accident was the air traffic controller's improper vectors that positioned the airplane inside the outer marker while it was still well above the glide slope. Contributing to the stall and loss of control was the accumulation of airframe ice that degraded the aerodynamic performance of the airplane."
Accident investigation:
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Investigating agency: | NTSB |
Status: | Investigation completed |
Duration: | 1 year and 10 months | Accident number: | NTSB/AAR-91-06 | Download report: | Final report
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Classification:
Icing
Landing after unstabilized approach
Loss of control
Sources:
» NTSB Safety Recommendations A-94-70 through -72
» Ian Churchill
» NTSB Safety Recommendations A-92-59 through -65
» NTSB/AAR-91/06
Follow-up / safety actions
NTSB issued 7 Safety Recommendations
Issued: 26-SEP-1990 | To: FAA | A-90-133 |
IMMEDIATELY TERMINATE THE PRACTICE, AT THE SEATTLE AIR ROUTE TRAFFIC CONTROL CENTER, OF PROVIDING RADAR VECTORS TO THE FINAL APPROACH COURSE WHEN USING A RADAR DISPLAY SET TO AN EXPANDED RANGE AND WHEN USING A VIDEO MAP ON WHICH THE APPROACH GATE IS NOT DEPICTED. (Closed - Acceptable Action) |
Issued: 26-SEP-1990 | To: FAA | A-90-134 |
AT AIR ROUTE TRAFFIC CONTROL CENTERS THAT PROVIDE EN ROUTE SERVICE, IMMEDIATELY TERMINATE THE PRACTICE OF PROVIDING RADAR VECTORS TO THE FINAL APPROACH COURSE WHEN USING A RADAR DISPLAY SET TO AN EXPANDED RANGE AND WHEN USING A VIDEO MAP ON WHICH THE APPROACH GATE IS NOT DEPICTED. (Closed - Acceptable Action) |
Issued: 19-NOV-1991 | To: FAA | A-91-122 |
Issue an operations bulletin to the principal operations inspectors of 14 CFR 121 and Part 135 air carriers to verify that air carriers have established procedures for flightcrews to take appropriate actions when they have encountered icing conditions during a flight, to check for the presence of, and to rip airplanes of accumulated airframe ice prior to initiating final approach, in accordance with airplane manufacturers\' recommendations on the use of deice systems. (superseded by A-94-71) (Closed - Acceptable Action/Superseded) |
Issued: 19-NOV-1991 | To: FAA | A-91-87 |
AMEND THE ICING CERTIFICATION RULES TO REQUIRE FLIGHT TESTS WHEREIN ICE IS ACCUMULATED IN THOSE CRUISE AND APPROACH FLAP CONFIGURATION IN WHICH EXTENSIVE EXPOSURE TO ICING CONDITIONS CAN BE EXPECTED, AND REQUIRE SUBSEQUENT CHANGES IN CONFIGURATION, TO INCLUDE LANDING FLAPS. (Closed - Acceptable Action) |
Issued: 19-NOV-1991 | To: FAA | A-91-88 |
REVIEW THE AIRRAME ICING CERTIFICATION DATA FOR EXISTING PART 23 AND PART 25 AIRPLANES TO VERIFY THAT THE FLIGHT PROFILES EXAMINED INCLUDED ICE ACCUMULATED AT THOSE CRUISE AND APPROACH FLAP CONFIGURATIONS IN WHICH EXTENSIVE EXPOSURE TO ICING CONDITIONS CAN BE EXPECTED, WITH SUBSEQUENT CHANGES IN CONFIGURATION, TO INCLUDE LANDING FLAPS. REQUIRE ADDITIONAL FLIGHT TESTS AS NECESSARY. (Closed - Acceptable Action) |
Issued: 19-NOV-1991 | To: FAA | A-91-89 |
REQUIRE MANUFACTURERS TO REVIEW THE PNEUMATIC DEICE BOOT SYSTEM DESIGNS FOR AIRCRAFT USED IN 14 CFR PARTS 121 AND 135, TO ENSURE THAT THE PNEUMATIC PRESSURE THEREHOLD AT WHICH EACH DEICE BOOT INDICATION LIGHT IS DESIGNED TO ILLUMINATE IS SUFFICIENT PRESSURE FOR EFFECTIVE PNEUMATIC DEICE BOOT OPERATION, AND ISSUE AIRWORTHINESS DIRECTIVES TO MODIFY SYSTEMS FOUND TO BE DEFICIENT IN THIS REGARD. (Closed - Acceptable Action) |
Issued: 19-NOV-1991 | To: FAA | A-91-90 |
REVISE ADVISORY CIRCULAR (AC) 20-73, "AIRCRAFT ICE PROTECTION," AND AC 23.1419-1, "CERTIFICATION OF SMALL AIRPLANES FOR FLIGHT IN ICING CONDITIONS," TO INCLUDED GUIDANCE FOR THE FULFILLMENT OF 14 CFR PARTS 23.1416(C) AND 25.1416(C) BY ENSURING THAT PNEUMATIC PRESSURE THRESHOLD AT WHICH EACH DEICE BOOT INDICATION LIGHT IS DESINGED TO ILLUMINATE IS SUFFICIENT PRESSURE FOR EFFECTIVE PNEUMATIC DEICE BOOT OPERATION. (Closed - Acceptable Alternate Action) |
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Photos
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does
not display the exact flight path.
Distance from Yakima Air Terminal, WA to Pasco-Tri-Cities Airport, WA as the crow flies is 114 km (71 miles).
Accident location: Exact; deduced from official accident report.
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.