# NTSB CEN23LA172: Piper PA-34-200, N28HE, Coldspring, TX, May 3, 2023 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: May 3, 2023, 13:29 local (18:29 UTC) - Place: Coldspring, TX · 8mi West of Cold Spring, TA and 3 mi north of SH150 - Coordinates: 30.578177, -95.177608 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.5782&lon=-95.1776&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 107813 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA172 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/107813/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=107813 - Page: https://openairdocs.org/ntsb/CEN23LA172 ## Probable cause The stabilator trim rod assembly separated from the stabilator link assembly due to a missing connecting bolt, which resulted in the pilot’s inability to maintain pitch control of the airplane. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system: elevator tab control system](https://openairdocs.org/ntsb-findings/01022731): Aircraft › Aircraft systems · Not installed/available (probable cause); cases with it: [Piper PA-34-200, 1 case](https://openairdocs.org/ntsb-findings/01022731/cases.md?model=7103405), [All aircraft, 37 cases](https://openairdocs.org/ntsb-findings/01022731/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Piper PA-34-200, 2 cases](https://openairdocs.org/ntsb-events/333/sequence.md?model=7103405), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Maneuvering: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Piper PA-34-200, 5 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=7103405), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-34-200, 3 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7103405), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis According to the pilot examiner, following steep turn maneuvers, they heard a loud “pop” from the tail of the airplane, the nose abruptly pitched up, and the airplane entered an accelerated stall. He took control of the airplane and added power to recover from the stall, at which time they heard another loud bang and the nose of the airplane pitched abruptly down. He reduced power to idle, there was another bang, and once again, the airplane pitched up uncontrollably. This time he did not add power and the nose of the airplane pitched down, but not as severely and he was able to use the engine power to dampen the pitch oscillations. Unable to maintain full control of the airplane, he elected for an emergency, off-airport landing. The airplane contacted trees while on approach to the field. The airplane landed hard, bounced, and slid through a rough, muddy field, which resulted in substantial damage to both wings, the fuselage, and empennage. A postaccident examination revealed that the bolt that connects the stabilator trim rod assembly to the stabilator link assembly was missing and not located. Since the bolt was not recovered, the reason for the separation could not be determined. Without being able to determine the reason for the separation, the flight school proactively inspected all same model airplanes in their fleet and replaced the bolt on each of them. ## Factual narrative On May 3, 2023, about 1329 central daylight time, a Piper PA-34-200 airplane, N28HE, sustained substantial damage when it was involved in an accident near Coldspring, Texas. The pilot examiner and flight instructor sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 pilot certification flight. According to the pilot examiner, following steep turn maneuvers, they heard a “loud metallic bang” from the tail of the airplane and the control yoke abruptly went to the full nose-up position. He stated the nose of the airplane pitched up rapidly, and the stall warning went off as they entered an accelerated stall. He took control of the airplane and applied full power to recover from the stall, at which time they heard another loud bang from the tail and the nose of the airplane pitched abruptly down. He reduced power to idle, there was another bang, and once again the airplane pitched up uncontrollably. This time he did not add power and the nose of the airplane pitched down, but not as severely and he was able to use the engine power to dampen the pitch oscillations. Unable to maintain full control of the airplane, he elected for an emergency, off-airport landing. While on the final approach, as the airplane clipped the tops of trees, the pilot examiner pulled the mixture controls to cutoff. Upon touchdown, the airplane bounced then slid through a rough, muddy field, which resulted in substantial damage to both wings, the fuselage, and empennage. A postaccident examination revealed that the bolt (item 49 in figure 1) which connects the stabilator trim rod assembly (item 12) to the stabilator link assembly (item 13) was missing. (Figure 2) Figure 1. Illustrated Parts Catalog (Part Nos. 753-816) Figure 2. Photo of the stabilator trim assembly (Photo courtesy of the FAA) A review of applicable maintenance records revealed two maintenance logbook entries for the elevator trim wheel cable becoming unspooled, the first on March 14, 2023, and the second on March 23, 2023. After each repair, a functional check flight was accomplished with no discrepancies noted. In an interview with the mechanic from the March 23 repair, he stated that he did not disconnect or otherwise perform maintenance on the affected control rod or linkage. The pilot examiner stated that during the preflight inspection, no anomalies were noted with the trim linkage assembly. Following the accident, the flight school inspected all PA-34 airplanes in their fleet and replaced the affected bolt on each airplane. ## Aircraft - Registration: [N28HE](https://openairdocs.org/deregistered/N28HE-2024-02-28), registration cancelled 2024-02-28, S/N 34-7350278, built 1973 (OpenAirDocs) - Reported make and model: PIPER PA-34-200 - Registry model: [Piper PA-34-200](https://openairdocs.org/model/piper-pa-34-200) (registry code 7103405) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 34-7350278 - Year built: 1973 - Engines: Lycoming IO360 200 horsepower reciprocating; Lycoming LIO-360 200 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Wings Over Texas Holdings LLC - Registered owner: Wings Over Texas Holdings LLC - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 7, 2023 - Departed: KCXO, Conroe, TX - Airport: NA - Equipment: Stall warning system, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 69; injuries: serious; airline transport, flight instructor; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, waiver time limited special; seat: right; restraint: 3-point - Pilot; age 21; injuries: serious; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review August 5, 2022; seat: left; restraint: 3-point ## Weather - Conditions: Visual (VMC), Day - Wind: 100° at 8 knots - Visibility: 10 statute miles - Temperature: 82 °F, dew point 64 °F - Altimeter: 29.96 inHg - Observed at: KCXO, 5 nm away - METAR: KCXO 031753Z 10008KT 1OSM FEW040 28/18 A2996 RMKAO2 SLPI41 T02780178 10278 20167 58017 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20230503011539A](https://openairdocs.org/incident/20230503011539A), May 3, 2023: Piper PA-34-200, Conroe, TX, Substantial damage. I was conducting a check ride for multi-engine commercial for student. We started at 12:00 but departed cxo at 12:30. Before departure the plan was briefed, a… ## Docket (4 files) The files NTSB released with the investigation on October 5, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=107813. 358 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 14 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15932514&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Maintenance records (item 2, PDF, 6 pages, 356 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15933055&FileExtension=pdf&FileName=Logbook%20Records_Redacted-Rel.pdf - Maintenance personnel interview summary (item 3, PDF, 2 pages, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15933278&FileExtension=pdf&FileName=Mechanic%20Interview-Rel.pdf - Photos (item 4, PDF, 2 pages, 647 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15932883&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.