Cessna 550 N744AT

Summary

On 9 May 2019 at about 16:28 local time, a Cessna 550 registered N744AT, operated by Air Ambulance By Air Trek Inc, was involved in an incident near Savannah, Georgia, United States. 7 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

9 May 2019 at 16:28

Classification

Incident

Location

Savannah, Georgia, United States

Nearest airport

Savannah/Hilton Head Intl (SAV)

Coordinates

32.1292, -81.2008

Aircraft

Cessna 550

Registration

N744AT

Category

Airplane

Year built

1983

Engines

2

Operator

Air Ambulance By Air Trek Inc

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Naples → Niagara Falls

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

ERA19IA178

Nobody was injured.

The lineman's inadvertent introduction of diesel exhaust fluid (DEF) to the fuel truck fuel system icing inhibitor reservoir, which resulted in fuel contamination and a total loss of engine power. Contributing to the accident was the fixed-base operator's failure to ensure that DEF was stored off-airfield in accordance with their own policy.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The crew of the air medical flight reported that, while in cruise flight at 35,000 ft mean sea level, the left engine began losing power. The crew requested a lower altitude from air traffic control, shut down and secured the left engine, and diverted. While descending, the right engine lost all power, and the crew performed an uneventful forced landing to the diversion airport. Several days after the incident, the lineman who worked at the fixed-base operator (FBO) where the airplane was most recently fueled realized that he had inadvertently combined the contents of an unmarked, partially empty container of fuel system icing inhibitor (FSII) with a partially-empty container of diesel exhaust fluid (DEF), assuming that both containers contained FSII. The container of DEF was co-located with the container of FSII, which was contrary to the FBO's policy of isolating DEF off-airfield. The lineman then serviced the fuel truck FSII reservoir with the DEF/FSII combination. The following day, the incident airplane was fueled with Jet A fuel from the truck, and FSII additive from the truck was mixed at the time of fueling. Postincident testing revealed the presence of urea, one of the primary components of DEF, in the incident airplane's fuel system samples. When combined with hydrocarbon jet fuels, urea forms a solid precipitate, or clathrate, that is known to interfere with fuel filtering and fuel system operation. The presence of DEF in the incident airplane's fuel system resulted in a blockage, which led to the total loss of engine power.

Quoted verbatim from the NTSB record.