PIPER PA-25-235

Full Narrative

HISTORY OF FLIGHTOn May 17, 2023, about 1235 eastern daylight time, a Piper PA-25-235, N430AB, was destroyed when it was involved in an accident near Hollywood, Florida. The commercial pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 banner tow flight.
Radar data revealed that the pilot departed the North Perry Airport (HWO) about 1225 and completed two passes over the airport before proceeding east-northeast about 1229. After 1229, through the end of the flight, the airplane's groundspeed averaged about 55 kts, with a minimum speed about 48 kts and a maximum speed about 62 kts. The airplane reached a maximum altitude of about 800 ft about 1230 before descending to 700 ft about 1 minute later. Over the remainder of the flight, the airplane's altitude varied between 400 and 600 ft. About 1233, the airplane entered a descent that continued until the end of the flight. The airplane impacted the terrain and a postimpact fire ensued.
Communications between the pilot and the HWO tower controller revealed that about 1231, the controller stated, “Banner 430AB, everything okay? You are descending rapidly.” The pilot replied, “I’m trying to uh…keep climbing.” Less than 2 minutes later, about 1233, the controller stated, “Banner zero alpha bravo, you okay sir? I’m showing you at 600 feet now.” The pilot replied, “I’m good now, zero alpha bravo… starting to climb.” The controller then issued a frequency change to the Ft. Lauderdale (FLL) tower controller. The pilot established communications with the FLL tower controller and did not mention any concerns nor did he declare an emergency. At 1234, the pilot transmitted on the FLL frequency, “I might have to drop this banner. I’m not climbing. Zero alpha bravo.” The controller asked if the pilot would like to return to HWO and the pilot replied, “I’m at 400 [feet]. I gotta drop this banner over a lake… I’m going to be over these oil tanks with like a lake next to it.” There were no further communications from the pilot.
According to the operator’s director of ground operations, who supervised the flight from the banner pickup point and monitored communications with a handheld radio, the pilot departed around 1225 from runway 28R. He reported that the pilot picked up the banner at 1229, after a first pass for hook deployment and verification. The pilot then performed a right climbing turn (per airport procedure), and continued on the downwind leg of the traffic pattern at an altitude of about 600 ft mean sea level heading eastbound and communicating with the HWO tower controller. The ground operations director stated that everything appeared to be normal, and that he was watching the airplane when he heard the tower controller ask the pilot if he was “ok,” because the airplane was not climbing. The ground operations director tried to contact the pilot via radio when he saw that the airplane was not climbing but did not receive a response from the pilot. He further stated that the airplane had a high nose-up pitch attitude that was “more than needed” and, in his opinion, was preventing the airplane from climbing. He stated that he did not hear any engine roughness during the flight.
Open-source news video depicted the final seconds of the flight and showed the airplane in level flight at low altitude, near rooftop height, in a nose-high pitch attitude. The moment the banner was released, the airplane rolled and yawed right, before the wings leveled and it descended vertically in a nose-up attitude. The airplane then rolled left and entered a steep, nose-down, left spiraling descent out of the camera’s view. Low resolution surveillance video captured the banner release, the right and left rolls, and then the spiraled, vertical, nose-down collision with the street, where the airplane came to rest and subsequently caught fire. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with ratings for airplane single-engine land and sea, multi-engine land and sea, and instrument airplane. His most recent Federal Aviation Administration (FAA) first-class medical certificate was issued on November 14, 2022. According to the operator, the pilot had a total of 324 total hours of flight experience, of which 15 hours were in the accident airplane make and model.
Company records revealed that the pilot was hired 5 weeks before the accident. In an interview, the company’s chief pilot said the new-hire training included 40 to 80 hours of classroom, ground, and flight training. The pilot’s training records revealed that he had completed several written and practical examinations. WRECKAGE AND IMPACT INFORMATIONThe airplane was examined at the accident site and all major components were accounted for at the scene. The airplane came to rest upright facing a southerly direction. The entire airplane was consumed by fire. The engine was separated from its mounts but remained attached by wires and cables. The propeller was separated at the flange and rested behind the right aileron. The cockpit and instrument panel were consumed by fire. The single seat frame was dislodged from its mounts and distorted by impact and fire.
Control continuity was confirmed from the flight controls to all flight control surfaces. The flap handle was found securely in the “first notch” position, which corresponded to 10° of flaps.
The banner retention/release system revealed continuity of the Nos. 1, 2, and 3 cables to their respective retention/release locks. The cabling was fused by heat, and the system could not be tested from the cockpit. The airframe tail section to which the system was mounted, along with about 24 inches of each cable, was sectioned from the airplane and tested. All three retention/release mechanisms functioned as designed when each individual cable was actuated.
Examination of the engine revealed significant damage by impact and fire. The crankcase was fractured at its front behind the propeller flange. The crankshaft would not rotate due to impact damage to the crankcase. The engine accessories (magnetos, fuel control) were damaged by impact and fire and could not be tested. Examination of the cylinders with a lighted borescope revealed normal operating signatures and no anomalies. There was no evidence of foreign object ingestion or detonation. The valvetrain was rotated through the camshaft and revealed continuity and normal lift action throughout.
The fixed-pitch propeller with the attached crankshaft flange was separated from the engine’s crankshaft. The fracture surface signatures were consistent with torsional overload. Both blades showed similar twisting, bending, leading-edge gouging, and chordwise scratching.
The fuel manifold was secure, and disassembly revealed that the inner diaphragm was intact and pliable. The fuel lines were secure, and the nozzles were unobstructed. The No. 1 fuel injection nozzle was installed, but not fully seated, and it displayed evidence of worn threads.
The engine examination revealed no pre-impact mechanical anomalies that would have prevented normal operation. ADDITIONAL INFORMATIONAccording to the manufacturer’s Owner’s Handbook, Section III, page 16, STALLS, “In any attitude or under any loading condition the stall is preceded by a moderate aerodynamic buffet and a proportional decrease in stick forces. All controls are effective up to and completely through the stall and there is no noticeable tendency to enter a spin after the stall.”
“With agricultural equipment installed, the flaps down stall speed is 61 MPH, flaps up 62 MPH.” The manual did not contain references to stall speeds in any other configuration.
The operator’s training manual stated:
The Pawnee, while a sixty plus year old design, are still a wonderful and capable aircraft easily able to perform the task at hand so long as they are operated within the boundaries of their design. Originally designed for aerial application (crop dusting), they are lifting machines. This translates quite well into banner towing offering more than enough power to pull the largest of billboards. Unfortunately, this excess of power may lead some pilots to believe that they can simply “throttle” out of trouble. Regardless of the amount of horsepower on board, if you are low (as is often true in banner ops) and get too slow you could be facing an unrecoverable stall or spin. Remember, as bank angle increases so does the airspeed at which the wing stalls. Just because you’re in the green arc doesn’t mean the aircraft won’t stall, especially if uncoordinated. ALWAYS keep the ball centered. Another occasion when a banner tow pilot could demand too much of his or her aircraft is after the banner is released. It is often described that once the drag and weight of the banner is no longer holding the aircraft back that it feels “free.” REMEMBER, the Pawnees are made for lifting and are not “sporty” aerobatic aircraft. Fly it like a normal category aircraft; even though it feels like it will easily snap roll or perform a loop it won’t, and even if it would, it is illegal.
After the accident, a former employee of the operator submitted a written statement describing his experience flying the accident airplane. He reported 180 total hours of flight experience in the Piper PA-25, of which 34 hours was in the accident airplane. He stated that he was taught to perform banner-tow operations at 55 mph indicated airspeed (IAS), but that the airplane exhibited stall characteristics at 70 mph IAS.
In his statement, the pilot offered a brief tutorial based on his understanding of stall characteristics of the PA-25 with a banner in tow. He said:
The stalling characteristics of the PA25 are significantly different when a banner is attached to the plane. The banner is dragging the tail down and adding directional stability, keeping the airplane from spinning. The weight of the banner is also adding downward pressure on the tail, keeping the nose from dropping. The airplane will continue in a nose up attitude, but it will be descending. The pilot will experience the “region of reverse command”, where the maximum thrust is applied, and the aircraft is pitched up, but not climbing. The nose must be lowered to get the airplane to climb. This applies regardless of the stall speed. However, if the pilot is not aware of a higher stall speed, the pilot may be looking at the airspeed indicator and seeing a speed much higher than the published stall speed and not understand why the aircraft isn’t climbing. This is what happened to me when I was towing for the first time in N337AB. The airplane maybe stalling, but because of the attached banner, it does not exhibit the normal series of stall characteristics.
The former employee said when he reported the experience, he was told to “write it up,” which he did. However, a review of maintenance records revealed no evidence of airspeed discrepancies, no corrective actions, nor pitot/static systems checks in the 10 months and about 125 aircraft hours between his experience and the date of the accident.
According to the operator’s training manual:
In this Training Manual, target airspeeds are given (e.g. 95 MPH for the pick, 70 MPH after the push over, etc); however, the accuracy of airspeed indications in Pawnee aircraft differ from airplane to airplane. Additionally, configuration of the windows alters the static source input to the pitot system. For example, flying with the windows closed can cause an indication difference of up to 10 MPH. Pilots should become familiar with the airspeed indications and flight characteristics of each individual airplane. When flying a particular Pawnee for the first time, fly toward the west training area at a safe altitude to determine stall speed and handling characteristics in the configuration (i.e. flaps and windows) you will be using for picking and towing.
Unable to Climb With a Banner
If you experience difficulty in climbing after picking a banner, or are unable to climb at all, consider the following: first, step on the ball and coordinate the airplane. Even a slightly cross controlled condition will inhibit climb performance. Next, adjust your airspeed. You may be trying to climb at too slow a speed and in the incipient stage of a stall. Lower the nose slightly to gain 5 to 10 MPH which may improve climb performance. Advise Tower that you want to return to the banner box and also advise company. As you proceed back toward the banner box you may encounter lift from thermals which will produce a slight improvement in climb performance. If you are still unable to climb, plan on dropping the banner in the banner field. If you manage to climb to 1,300 feet over the banner box make your decision whether it is safe to continue to the display area. If not, advise company and follow ground crew instructions to drop in the banner field. Try to avoid dropping the banner off airport, but if you are unable to maintain altitude find a safe area to drop the banner, advise company ground, then comply with the Lost Banner Enroute procedure (Pg 33).
The procedure outlined in company training documents and covered in two separate written exams completed by the accident pilot included the following in both multiple choice and fill-in-the-blank format: 1. Verify full power 2. Achieve coordinated flight. 3. Lower the nose to gain airspeed and attempt climb. 4. Steep turn into the wind if possible.
Despite the airplane’s apparent lack of climb performance and its failure to meet target altitudes prescribed in the training manual, the pilot continued a generally eastbound heading toward the coastline and his assigned route, rather than returning to HWO. During the low-altitude flight, and before reaching the location where the pilot ultimately dropped the banner, the airplane overflew a public park and the athletic fields of two different schools. It is unknown if the fields were occupied or how their availability or occupancy may have affected the pilot’s decision making.