Accident Details
Probable Cause and Findings
The pilots’ improper in-flight weather evaluation and decision to continue the approach, which resulted in an encounter with a thunderstorm, a loss of airplane control, and collision with terrain. Contributing to the accident was the flight instructor’s inadequate preflight weather evaluation.
Aircraft Information
Registered Owner (Historical)
Analysis
On June 9, 2018, about 1500 eastern daylight time, a Piper PA-44-180 airplane, N21161, was substantially damaged when it was involved in an accident near Daytona Beach International Airport (DAB), Daytona Beach, Florida. The flight instructor and pilot-receiving-instruction sustained minor injuries. The flight was operated as a Title 14 Code of Federal Regulations Part 91 local instructional flight.
The flight instructor stated he and the pilot-receiving-instruction, who had the controls, departed DAB about 1400 in visual flight rules conditions. They practiced maneuvers and then landed at Flagler Executive Airport (FIN), Palm Coast, Florida. After departing FIN, a DAB tower controller issued the flight a local instrument clearance and provided wind and supplemental weather information, which included wind from 310° at 14 knots, gusting to 20 knots. The controller also issued a low-level windshear advisory, which included wind from 320° at 15 knots and a 15-knot gain 1 mile from the end of the runway. The controller also advised the pilot that the visibility was probably 1 mile in “that precipitation" and that there was “frequent lightning cloud to ground.” During the approach, the airplane encountered rain, which increased in intensity as the airplane neared the final approach fix (FAF). Shortly after passing the FAF and while the airplane was about 800 ft mean sea level, a DAB tower controller issued a low-altitude alert. The instructor took the flight controls, added full power, and attempted to climb the airplane. It continued descending while about 90 knots throughout the descent and upon impact with houses about 4 miles north of DAB. The airplane then came to rest inverted in a retention pond. Both wings outboard of the engines were separated.
The flight instructor stated they informally checked the weather before departing but did not obtain an official weather briefing before the flight. He further stated that thunderstorms were an everyday occurrence in the afternoon. When they departed FIN the storms were east of DAB, but they moved quicker than they anticipated.
A convective SIGMET advisory was valid at the time of the accident, and it warned of a line of severe thunderstorms about 20 miles wide with cloud tops above 45,000 ft above ground level (agl), hail to 1 inch, and possible wind gusts to 50 knots. A Center Weather Service Unit Center Weather Advisory was valid at the time of the accident, and it warned of an area of scattered developing thunderstorms with cloud tops to 40,000 ft agl and moderate-to-heavy precipitation.
Base reflectivity scans from around the time of the accident indicated very heavy rainfall and possible hail. Two hundred fifty-five lightning flashes occurred around the accident site between 1445 and 1505; the closest lightning occurred within 1,000 ft of the accident flight. See figure 1 for the base reflectivity scan from 1501.
Figure 1. Reflectivity scan at 1501 with the air traffic control flight track data points in pink and the lightning flashes as black dots.
The National Weather Service issued an amended terminal aerodrome forecast (TAF) at 1416, which was valid at the time of the accident and included temporary conditions between 1500 and 1700 ft agl of variable winds at 15 knots, gusting to 25 knots; 2 miles visibility; thunderstorm and heavy rain; and a broken ceiling of cumulonimbus clouds at 2,000 ft agl.
At 1444, the weather conditions reported at DAB, which was 4 miles from the accident site, included wind variable at 6 knots; visibility 9 statute miles; thunderstorms; cumulonimbus clouds at 2,500 ft agl; broken clouds at 4,100, 7,500, and 25,000 ft agl; temperature 28°C; dew point 23°C; and an altimeter setting of 30.09 inches of mercury (inHg).
At 1453, the weather conditions reported at DAB included wind from 300° at 14 knots, gusting to 19 knots; visibility 9 statute miles; thunderstorms; scattered cumulonimbus clouds at 2,500 ft agl; broken ceiling at 4,100 ft agl; broken clouds at 7,500 and 25,000 ft agl; temperature 27°C; dew point 22°C; and an altimeter setting of 30.09 inHg.
Two METARs issued by DAB just before and after the accident included lightning in the area farther than 10 miles and but less than 30 miles from the center of the airport and frequent in-cloud and cloud-to-ground lightning.
The FAA Advisory Circular AC 00-24C, "Thunderstorms," issued February 19, 2013, provides guidance to pilots on thunderstorm hazards and avoidance. The AC states that all thunderstorms “have conditions that are a hazard to aviation.
The following guidance is included for avoiding thunderstorms:
Chapter 10, “DOS AND DON'TS OF THUNDERSTORM AVOIDANCE.,” section A, “Thunderstorm Avoidance,” states, in part, the following:
Never regard any thunderstorm lightly, even when radar observers report the echoes are of light intensity. Avoiding thunderstorms is the best policy. Following are some dos and don'ts of thunderstorm avoidance:
(1) Don't land or takeoff in the face of an approaching thunderstorm. A sudden gust front of low-level turbulence could cause loss of control.
(17) Do regard as extremely hazardous any thunderstorm with top 35,000 ft or higher whether the top is visually sighted or determined by radar….
(19) Do divert and wait out the thunderstorms on the ground if unable to navigate around an area of thunderstorms.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# ERA18LA164