# NTSB CHI07LA035: Piper PA 46-350P, N46PT, Atlanta, GA, December 3, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 3, 2006, 11:14 local (16:14 UTC) - Place: Atlanta, GA - Coordinates: 33.754797, -84.390211 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.7548&lon=-84.3902&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 31, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration, New Piper Aircraft, Inc. - NTSB case key (mKey): 65030 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07LA035 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65030/pdf - Page: https://openairdocs.org/ntsb/CHI07LA035 ## Probable cause The exceedance of airplane design stress limits when the pilot did not maintain aircraft control after his attention was diverted to the right side attitude indicator during cruise flight. An additional cause was the aural detection for the autopilot disconnect was difficult to hear with the noise canceling headset. A contributing factor was the disengaged autopilot/flight director. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, cruise - aircraft control - not maintained, pilot in command (cause) - diverted attention, pilot in command (cause) - autopilot/flight director - disengaged (contributing factor) - flight/nav instruments,attitude indicator - failure,partial - visual/aural detection, pilot in command (cause) - vacuum system - obstructed - Airframe/component/system failure/malfunction, descent - uncontrolled - design stress limits of aircraft - exceeded, pilot in command (cause) - fuselage - bent - wing - bent ## Analysis The pilot reported that he heard a loud whistling noise while in level cruise at flight level (FL) 220 and noticed that the right side attitude indicator was "tilted." While he was leaning over adjusting the instrument, he realized that the airplane was in a dive. He leveled the wings and pulled out of the dive at FL 190. The autopilot (A/P) was re-engaged and the flight was completed to its intended destination without further incident. A visual examination after the descent revealed the left front baggage door open and buckled, and the left and right wings showed skin damage and wrinkling approximately 54 inches from the wing roots. When tested, the autopilot and flight director performed within test specifications with only "minor" deviations. Both vacuum pumps tested within test specifications. The right side attitude indicator continued to show a three degree turn even after a kink in the vacuum supply to the right side attitude indicator was removed. The "normal" static system leaked in excess of allowable limits; however, the valve was found to be in the "alternate" position before it was tested. An active noise-canceling set of headphones was found connected to the pilot's side of the cockpit. The A/P disconnect tone was found to be operating normally while the engine was at idle power. During the test, it was noted that the tone was difficult to hear while wearing the headset. ## Factual narrative On December 3, 2006, about 1114 eastern standard time, a Piper PA 46-350P, N46PT, owned and piloted by a private pilot, arrived with substantial damage at Indianapolis Metropolitan Airport (UMP), Indianapolis, Indiana. The pilot stated that the autopilot disengaged over Atlanta, Georgia, during cruise at flight level (FL) 220. The airplane then entered a "dive" from which he recovered at FL 190. The 14 CFR Part 91 personal flight was operating on an instrument rules flight plan. The private pilot and passenger were uninjured. The flight originated from Page Field Airport, Fort Myers, Florida, about 0823 and was en route to UMP. The pilot stated that he heard a "loud whistling noise" and noticed that the right side attitude indicator horizon was "tilted". He was leaning over the right front pilot seat while "focusing" and "adjusting" the right side attitude indicator horizon. He "soon" noticed that the right side heading indicator was turning. He sat up and "discovered" the airplane was in a "dive." He leveled the wings and pulled out of the "dive" at FL 190. The pilot then requested a climb back up to FL 200, and the flight was completed to UMP without further incident. The pilot reported that he re-engaged the autopilot and it worked "fine" for the rest of the trip. Upon a visual examination of the exterior of the airplane, the left forward baggage door was found open and buckled. Both wings had wrinkles and skin deformation in the upper skin surface approximately 54 inches from the wing roots. The damage to the left wing surface was more pronounced. Bench testing of the autopilot (A/P) computer and the flight director (FD) was conducted. Both units performed properly with only minor deviations. The FD was slow to come on but did stabilize and performed correctly. Both vacuum pumps were tested on the airplane, and operation was found to be normal with 5.1 psi of suction. The right side attitude indicator showed a three degree turn. The vacuum supply hose for the right side attitude indicator was found kinked at the upper outboard instrument panel support. The kink was removed and the right side attitude indicator continued to show a three degree turn. The pitot-static system was tested. The static supply source valve was found in the "alternate" position when the attempt to test and verify the altimeter and A/P altitude hold mode was conducted. The "alternate" static system tested within limits, however the "normal" static system leaked in excess of allowable limits. The A/P altitude hold mode operation tested normal. When simulated flight at FL 220 was conducted, the A/P made correct pitch trim inputs to the stabilizer when 25 foot altitude excursions above and below FL 220 were simulated. An operational check of the A/P and instruments under aircraft power was normal. An active noise-canceling set of headphones was found connected to the pilot's side of the cockpit. The A/P disconnect tone was found to be operating normally while the engine was at idle power. During the test, it was noted that the tone was difficult to hear while wearing the headset. ## Aircraft - Registration: [N46PT](https://openairdocs.org/aircraft/N46PT), registered now, S/N 4622108, built 1990 (OpenAirDocs) - Reported make and model: Piper PA 46-350P - Registry model: [Piper PA 46-350P](https://openairdocs.org/model/piper-pa-46-350p) (registry code 7104620) (OpenAirDocs) - Registry engine: [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series) (registry code 41533, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 4622108 - Airframe hours: 1925 - Engines: Lycoming TIO-540-A2A 350 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 1, 2006 - Departed: FMY, Ft. Meyers, FL - Destination: UMP, Indianapolis, IN - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review June 1, 2006; seat: left; flight hours: 2,700 total, 1,000 in this make and model, 2,640 as pilot in command, 30 in the last 90 days, 18 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Lowest ceiling: 19,000 ft overcast - Temperature: 43 °F - Altimeter: 29.92 inHg ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20061203029389I](https://openairdocs.org/incident/20061203029389I), Dec 3, 2006: Piper PA46350P, Atlanta, GA, Minor damage. (-23) On December 3, 2006, at approx. 1230 EST, Piper aircraft PA-46-350P, registration number N46PT while enroute from ft myers, page airport (kfmy) to… ## Other investigations on N46PT (1) 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. - [NTSB ERA10IA254](https://openairdocs.org/ntsb/ERA10IA254), Apr 25, 2010: Piper PA 46-350P (N46PT), Owensboro, KY, incident, minor damage. Probable cause: A failure of the pilot's side window due to undetected cracking around the lower aft portion of the storm window cutout. 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.