Cessna 550 incident near Savannah, Georgia, May 9, 2019
On May 9, 2019 at about 4:28 pm local time, a 1983 Cessna 550, registered N744AT, was involved in an incident during enroute (cruise) near Savannah, Georgia (Savannah/Hilton Head Intl airport). It was flown under charter and air-taxi rules (Part 135). No one was hurt; 7 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 9, 2019 · about 4:28 pm local time
- Place
- Savannah, Georgia · Savannah/Hilton Head Intl · map
- Type
- Incident
- Injuries
- No one was hurt; 7 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 550 No Series, built 1983 · all 550s on the register
- Registration
- N744AT · no longer on the register · serial 550-0017
- Damage
- Not recorded
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Fuel contamination during prior to flight
- Fuel contamination during enroute (cruise) defining event
- Loss of engine power (total) during enroute (cruise)
- Loss of engine power (total) during approach
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Incorrect action selection › Airport personnel
- cause Environmental issues › Physical environment › Object/animal/substance › Ground vehicle › Contributed to outcome
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Airport personnel
- cause Aircraft › Fluids/misc hardware › Fluids › (general) › Fluid type
- cause Aircraft › Fluids/misc hardware › Fluids › (general) › Incorrect service/maintenance
- factor Personnel issues › Task performance › (general) › (general) › Airport personnel
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: glider; instructor: gyroplane; instructor: helicopter; instructor: instrument airplane; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: glider; rotorcraft: gyroplane; rotorcraft: helicopter
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Maximum gross weight: 15,100 lb
- Landing gear: retractable
- Engine 1: Pratt & Whitney JT15D-4 (turbojet); 0 hours total
- Engine 2: Pratt & Whitney JT15D-4 (turbojet); 0 hours total
- Operator: Air Ambulance By Air Trek Inc
The flight
- Departed from: APF Naples FL at 3:00 pm
- Destination: IAG Niagara Falls NY
- Flight plan: IFR
- Runway 19, 7,002 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 120° at 12 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,200 ft; a few clouds at 2,700 ft
- Temperature: 79°F (26°C), dew point 66°F (19°C)
- Altimeter: 30.10 inHg
- Observation at 4:53 pm from SAV
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 4 | |||
| Passengers | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on October 9, 2020. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilots Statements | PDF, 3 pages | View Download |
| 2 | Lineman Statement and Interview Summary | PDF, 3 pages | View Download |
| 3 | Lineman Training Certificates | PDF, 6 pages | View Download |
| 4 | Airport FBO Changes After Incident | PDF, 1 page | View Download |
| 5 | Fuel Truck Log | PDF, 1 page | View Download |
| 6 | Chemical Analysis of Jet Fuel Contamination | PDF, 16 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.