NTSB ANC89IA059 — 1989-04-13 · BARROW, Alaska, United States

Current FAA registration · N100AP

Make / Model: DEHAVILLAND DHC-6 TWIN OTTER
Year of manufacture: 1967 · 22 years old at event
Engine: P&W CANADA PT6A-60A (1050 hp)
Seats / Engines: 16 seats · 2 engines
Last airworthiness date: 19790115
ADS-B equipped: Yes — Mode-S A004C2

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

N100AP De Havilland DHC-6-100 None

Probable cause & findings

THE PROPAGATION OF A FATIGUE CRACK FROM MULTIPLE ORIGINS DUE TO MANUFACTURING DEFECTS IN THE ELEVATOR BELLCRANK MOUNTING QUADRANT.

Factual narrative

THE AIRPLANE HAD JUST DEPARTED BARROW, AK, ON A SCHEDULED COMMUTER FLIGHT WITH FIVE PASSENGERS AND TWO CREW MEMBERS ON BOARD. UPON REACHING AN ALTITUDE OF 150 AGL, THE CONTROL YOKE WAS PULLED FORWARD OUT OF THE CAPTAIN'S HANDS AND PINNED AGAINST THE CONTROL PANEL. SIMULTANEOUSLY, THE NOSE OF THE AIRPLANE SUDDENLY PITCHED UP 60 DEGREES ABOVE THE HORIZON. THE CAPTAIN REDUCED POWER AND THE NOSE PITCHED 30 DEGREES BELOW THE HORIZON. THE FLIGHT CREW WAS EVENTUALLY ABLE TO MAINTAIN A LEVEL ATTITUDE BY POWER ADJUSTMENTS ALONE, AND RETURNED FOR A SAFE LANDING. INSPECTION REVEALED A FATIGUE FRACTURED ELEVATOR BELLCRANK MOUNTING QUADRANT, P/N C6CFM1142-1, RESULTING IN A COMPLETE LOSS OF ELEVATOR CONTROL. THE ELEVATOR BELLCRANK MOUNTING QUADRANT HAD BEEN IN SERVICE SINCE 1966 AND HAD BEEN OPERATING 17,826 HRS. THE FRACTURE OCCURRED BETWEEN THE VERTICAL STABILIZER STUB FIN ATTACHMENT BULKHEAD AND THE BELLCRANK. METALLURGICAL EXAM REVEALED MULTIPLE FATIGUE ORIGINS IN THE VICINITY OF SUPERFICIAL MACHINING ABRASIONS. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1989_ANC89IA059.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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