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WPR11CA308

2011-07-02 · Enumclaw, Washington, United States · Minor · 1 aircraft · Status: Completed

Airport 21W

Current FAA registration · N23TT

Make / Model
PIPER PA-18
Engine
CONT MOTOR C90 SERIES (95 hp)
Seats / Engines
2 seats · 1 engine
Last airworthiness date
19580915
ADS-B equipped
Yes — Mode-S A207E2

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

The pilot's failure to maintain an adequate airspeed during an encounter with a mountain wave and downdraft landing.

Factual narrative

The pilot reported that he was making an approach to an airstrip for a brief stop. He overflew the field and determined the wind was variable from the north and started his approach. On final he noticed an above average loss of altitude and speed due to a large mountain wave coming over the foothills to the west. He added power to compensate for the downdraft and continued on his landing approach. Once clear of some trees at the approach end of the runway he reduced the power to idle and was again pushed down by another downdraft. The pilot then added full power to arrest the airplane's decent but he did not have enough speed at that time to avoid a hard landing. The airplane slid off the runway and into a guard railing, which substantially damaged the fuselage tubular frame. The pilot reported that he was making an approach to an airstrip for a brief stop. He overflew the field and determined the wind was variable from the north and started his approach. On final approach he noticed an above average loss of altitude and speed due to a large mountain wave coming over the foothills to the west. He added power to compensate for the downdraft and continued on his landing approach. Once clear of some trees at the approach end of the runway he reduced the power to idle and was again pushed down by another downdraft. The pilot then added full power to arrest the airplane's descent but he did not have enough speed at that time to avoid a hard landing. The airplane slid off the runway and into a guard railing. The fuselage tubular frame sustained substantial damage. The pilot reported no mechanical problems that would have precluded normal operation. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

FAA avdata. C = Cause, F = Factor.

  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
  • C Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
  • C Environmental issues-Conditions/weather/phenomena-Wind-Windshear-Response/compensation - C
  • C Environmental issues-Conditions/weather/phenomena-Wind-Downdraft-Response/compensation - C

Verbatim from NTSB's published report. Source file NTSB_2011_WPR11CA308.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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