On September 8, 1998, a Piper PA-28-180 was involved in an aviation accident near Verkehrslandeplatz Langeoog, DE. No fatalities were reported. Investigators recorded the probable cause as: The aircraft was overloaded and the runway was wet, resulting in an insufficient takeoff distance. The aircraft lifted off with too low an airspeed and a high angle of attack, entering a stalled flight condition. This summary draws on records from the German Federal Bureau of Aircraft Accident Investigation (BFU); 4 related events involving the same aircraft type or operator are linked below.
A Piper PA-28-180 crashed into trees after takeoff from Langeoog on 8 September 1998, injuring four people. The aircraft was overloaded and the runway was wet.
Incident Overview and Casualties On 8 September 1998, a Piper PA-28-180 aircraft crashed into trees shortly after takeoff from Verkehrslandeplatz Langeoog (EDWL). The accident resulted in two serious and two minor injuries among the occupants. The aircraft was destroyed, and crop damage occurred. The pilot, who sustained minor injuries, freed himself from the wreckage and assisted the other passengers in exiting. A fire in the engine compartment was extinguished using a portable fire extinguisher. The injured were transported to Wittmund Hospital by SAR and Bundeswehr helicopters. ## Flight Details and Takeoff The pilot had landed at Langeoog from Wilhelmshaven at 1152 MESZ with two passengers on board. The plan was to pick up two more passengers and fly to Bad Neuenahr-Ahrweiler. After pre-flight preparations, including weight calculations and discussions with the flight controller about runway conditions, the aircraft took off from grass runway 24R at 1231 MESZ. The runway was wet, and the wind was from 210° at 12 kt. The pilot rotated in the middle of the runway and lifted off at 55 kt. However, the climb rate was insufficient to clear the trees and bushes in the departure path. The pilot decided to continue on the takeoff course, raise the nose, and land the aircraft on the treetops at minimum speed. The aircraft first touched down on the treetops with the tail and then nosed over. ## Investigation Findings The BFU investigator began the on-site investigation around 1600 hours. The aircraft's airworthiness certificate, registration certificate, noise certificate, and logbook were found at the scene. The aircraft was properly certified for air traffic. A technical defect (magnetic compass defective since 30 August 1998) was noted in the logbook but was not relevant to the accident. The last annual inspection was on 3 June 1998, with a total operating time of 3,065 hours. No defects affecting airworthiness were found. The aircraft impacted the ground with the nose first at an angle of approximately 30° to the ground. All parts showed signs of collision with branches, twigs, and tree trunks. The wings were almost completely separated from the fuselage, and the engine with cowl and lower forward fuselage were severely damaged. The fixed nose gear broke off. Minor damage was found in the cabin, and one propeller blade was severely deformed. The flaps were in the approximately 25° extended position. The fuel tanks in the wings were undamaged, and approximately 155 liters of fuel were recovered. The engine was obviously running at the time of impact, and no technical defects were found. The flight controls and other systems were checked on the wreckage, and no defects were found. The pilot was not wearing a shoulder strap during takeoff. ## Weight and Balance The calculated takeoff weight was 1,165.1 kg, indicating the aircraft was overloaded by approximately 75 kg (about 7%) at the time of takeoff. The maximum allowable takeoff weight was 1,090 kg. The center of gravity was within the manufacturer's specified limits. The pilot used an outdated weighing report from 20 August 1991 (629 kg) instead of the current one from 17 June 1997 (680.5 kg) for the empty weight calculation. ## Runway and Weather Conditions The airfield has two parallel grass runways, each 645 m long and 30 m wide. The elevation is 7 ft. From the end of marked grass runway 24R to the start of the tree and bush growth, there is a 30 m safety strip. The trees and bushes are initially 2 to 3 m high and 5 to 6 m high in the accident area. The accident site was in a small wood, about 1,450 m from the takeoff point on runway 24R and about 20° to the left of the departure direction. Weather conditions at the time of takeoff were: ground visibility 8 km, wind 210° at 12 kt, main cloud base at 800 ft with drizzle, temperature +16°C, QNH 1007 hPa. Visual meteorological conditions prevailed. Witnesses stated that the ground of the taxiways and runways was in a softened condition due to heavy rains in the previous days. A particularly muddy grass area of several square meters was present in the half-runway marking area. ## Takeoff Distance Calculation Based on the PA-28-180 flight manual, the takeoff roll distance for a dry paved runway was approximately 220 m. A 1% addition for each degree Celsius deviation from the standard temperature for pressure altitude (+15°C) resulted in a takeoff roll distance of approximately 222 m. The softened ground required a 60% addition for extremely wet ground, resulting in a takeoff roll distance of approximately 355 m. The takeoff distance over a 15 m obstacle was approximately 490 m from the manual. The 1% addition resulted in a distance of approximately 495 m. The addition of 60% resulted in a required takeoff distance of approximately 792 m. ## Assessment The aircraft was properly maintained and certified for air traffic. A technical defect noted in the logbook was not relevant to the accident. Sufficient fuel was on board. No technical defects were found. The aircraft was overloaded by approximately 75 kg (about 7%) at the time of takeoff. The center of gravity was within the allowable limits. The pilot used an outdated weighing report for the empty weight calculation. The pilot was aware of the orographic situation of the approach and departure at the airfield. The takeoff configuration chosen by the pilot corresponded to the flight manual for a short runway takeoff. The takeoff process was observed by witnesses both on board and on the ground. The aircraft lifted off relatively flat just before the end of the runway. It is very likely that the aircraft had too low a speed during the liftoff phase and entered a stalled flight condition. The climb was continued near or in a stalled flight condition. As a result, neither a higher airspeed nor sufficient altitude could be achieved to safely clear the obstacles. After recognizing the obstacles and realizing that a safe overflight was not possible, the pilot decided to land on the obstacles (treetops). The pilot's statement that he calculated the takeoff roll or takeoff distance over a 15 m obstacle with a 30% addition for wet ground with good grass cover could not be followed. Three witnesses stated in writing that the ground was heavy and wet at the time of the aircraft's takeoff. The required takeoff distance over a 15 m obstacle under the existing conditions was approximately 792 m. The available takeoff distance was 645 m (without considering the existing 30 m safety strip in the departure direction). A safe takeoff was not possible under these conditions. As a result of the insufficient takeoff distance, the aircraft lifted off with too low an airspeed and a high angle of attack (probably near or in a stalled flight condition). This flight condition did not allow a normal climb, i.e., an increase to the prescribed 85 kt, and the assumption of the prescribed 15 m over obstacles.
Probable cause
The aircraft was overloaded and the runway was wet, resulting in an insufficient takeoff distance. The aircraft lifted off with too low an airspeed and a high angle of attack, entering a stalled flight condition. The pilot was unable to clear the obstacles and decided to land on the treetops.