Saturday, March 30, 2019

Swearingen SA227-TT, N6UP, registered to and operated by AIRCO JN LLC as a Title 14 Code of Federal Regulations Part 91 corporate flight, N6UP: Accident occurred January 19, 2018 at Ellington Airport (KEFD), Houston, Harris County, Texas

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Houston, Texas

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf


Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf


http://registry.faa.gov/N6UP

Location: Houston, TX
Accident Number: CEN18LA086
Date & Time: 01/19/2018, 1630 CST
Registration: N6UP
Aircraft: SWEARINGEN SA227 TT
Aircraft Damage: Substantial
Defining Event: Electrical system malf/failure
Injuries: 4 None
Flight Conducted Under: Part 91: General Aviation - Executive/Corporate

Analysis

During a corporate flight, as the pilots climbed the airplane to flight level 180, both electrical generators failed and would not reset. The pilots attempted to troubleshoot the problem but could not regain electrical power. The airplane's battery power was rapidly deteriorating, so the pilots declared an emergency and diverted to the nearest airport. Due to the loss of electrical power, the pilots lost communications and had to manually extend the landing gear. They could not verify, with air traffic control tower personnel, if the landing and nose gear were extended and locked. The pilots made a forced landing with the nose landing gear not fully extended, causing the airplane to skid on the forward fuselage after touchdown and substantially damaging the engines.

Postaccident examination of the airplane revealed the right generator current limiter had failed. A mechanic connected a battery to the airplane, and the left propeller immediately began to rotate. The mechanic determined that there was uncommanded voltage to the left starter, which was caused by a failure of the left starter relay when the engine was started before the flight. During the flight, the right generator was managing all of the airplane's electrical load, the cumulative electrical load exceeded the capacity of the right generator current limiter, and the generator failed. At that point, the airplane's electrical load was only being supplied by battery power, which was quickly depleted. Postaccident examination of the nose landing gear did not identify a mechanical reason to explain why the nose landing gear did not extend during the pilots' emergency landing gear extension procedure.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The failure of the left starter relay during engine start, which resulted in a loss of electrical and battery power during the flight and led to a forced landing with the nose landing gear not fully extended, causing substantial damage to the engines.

Findings

Aircraft
AC power distribution system - Failure (Cause)
Nose/tail landing gear - Incorrect use/operation (Cause)

Factual Information 

On January 19, 2018, about 1630 central standard time, a Swearingen SA227-TT airplane, N6UP, had an electrical malfunction during climb, and the flight crew executed a forced landing to Ellington Airport (EFD), Houston, Texas. The two pilots and two passengers were not injured, and the airplane sustained substantial damage to both engines during landing. The airplane was registered to and operated by AIRCO JN LLC, Freedom, Oklahoma, as a Title 14 Code of Federal Regulations Part 91 corporate flight. Visual meteorological conditions prevailed at the time of the accident, and an instrument flight rules flight plan had been filed. The flight departed Beaumont, Texas, at 1515, and was destined for Uvalde, Texas.

According to the pilots, during climb about 18,000 ft, both generators failed and would not reset. The pilots attempted to troubleshoot the problem and could not regain electrical power. The battery power was rapidly deteriorating so the pilots declared an emergency and diverted to EFD as the nearest airport. Due to the loss of electrical power, the pilots lost communications and also had to manually extended the landing gear. They could not verify if all the landing gear were extended and locked with the control tower personnel. During the forced landing, the nose landing gear was retracted, and the airplane skidded on the forward fuselage after touchdown. Due to the nose gear being retracted during the landing, both propeller assemblies and engines sustained substantial damage.

Examination of the airplane by Federal Aviation Administration inspectors and a mechanic revealed the right generator current limiter was failed (blown). The mechanic connected a battery to the airplane and the left propeller immediately began to rotate. After troubleshooting, the mechanic determined there was uncommanded voltage to the left starter which was caused by the left starter relay that failed at the engine start prior to the flight. During the flight, the right generator was managing all the airplane's electrical load, and the cumulative electrical load exceeded the capacity of the right generator current limiter and it failed. At that point, the airplane electrical load was only being supplied by battery power.

According to the mechanic, on January 2, 2018, the emergency landing gear extension was successfully tested during the airplane's most recent inspection. During the postaccident examination, a mechanical reason for the nose landing gear not extending during the pilots' emergency landing gear extension procedure could not be determined. 

History of Flight

Enroute-cruise
Electrical system malf/failure (Defining event)

Landing
Landing gear not configured

Pilot Information

Certificate: Airline Transport; Commercial
Age: 64, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 04/17/2017
Occupational Pilot: No
Last Flight Review or Equivalent: 10/21/2017
Flight Time:  21850 hours (Total, all aircraft), 4000 hours (Total, this make and model), 21000 hours (Pilot In Command, all aircraft), 120 hours (Last 90 days, all aircraft), 40 hours (Last 30 days, all aircraft), 10 hours (Last 24 hours, all aircraft) 

Co-Pilot Information

Certificate: Commercial; Private
Age: 64, Male
Airplane Rating(s):  Multi-engine Land; Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: 4-point 
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 10/24/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 10/21/2017
Flight Time:  10000 hours (Total, all aircraft), 8000 hours (Pilot In Command, all aircraft), 100 hours (Last 90 days, all aircraft), 30 hours (Last 30 days, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Manufacturer: SWEARINGEN
Registration: N6UP
Model/Series: SA227 TT TT
Aircraft Category: Airplane
Year of Manufacture: 1981
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: TT-441
Landing Gear Type: Retractable - Tricycle
Seats: 10
Date/Type of Last Inspection: 01/02/2018, 100 Hour
Certified Max Gross Wt.: 12500 lbs
Time Since Last Inspection:
Engines: 2 Turbo Prop
Airframe Total Time: 9258.4 Hours at time of accident
Engine Manufacturer: Garrett
ELT: C91  installed, not activated
Engine Model/Series: TPE 331
Registered Owner: AIRCO JN LLC
Rated Power: 900 hp
Operator: AIRCO JN LLC
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: EFD, 32 ft msl
Observation Time: 1550 CST
Distance from Accident Site: 0 Nautical Miles
Direction from Accident Site: 0°
Lowest Cloud Condition: Clear
Temperature/Dew Point: 10°C / 9°C
Lowest Ceiling: Overcast / 600 ft agl
Visibility: 5 Miles
Wind Speed/Gusts, Direction: 9 knots, 80°
Visibility (RVR):
Altimeter Setting: 30.17 inches Hg
Visibility (RVV):
Precipitation and Obscuration: Light - Rain
Departure Point: Beaumont, TX (BPT)
Type of Flight Plan Filed: IFR
Destination: Uvalde, TX (UVA)
Type of Clearance: IFR
Departure Time: 1515 CST
Type of Airspace: Class B

Airport Information

Airport: Ellington Airport (EFD)
Runway Surface Type: Concrete
Airport Elevation: 32 ft
Runway Surface Condition: Wet
Runway Used: 17R
IFR Approach: None
Runway Length/Width: 9001 ft / 150 ft
VFR Approach/Landing: Straight-in

Wreckage and Impact Information

Crew Injuries: 2 None
Aircraft Damage: Substantial
Passenger Injuries: 2 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 4 None
Latitude, Longitude:  29.607222, -95.158611 (est)

No comments: