Accident
On 23 February 2018 at 1635 UTC, a Jabiru J400 (registration G-REAF) sustained damage during a training landing at Peterborough (Conington) Airport, Cambridgeshire. The aircraft was manufactured in 2010 (serial PFA 325-14502) and powered by a single Jabiru 3300A piston engine. The flight was a training sortie with two crew on board; no passengers were carried. Both crew members reported no injuries. Damage included a collapsed nose landing leg, distorted firewall and cockpit floor, a damaged propeller, and an engine shock load.
History of the Flight
The aircraft had recently been purchased by a pilot holding a Private Pilot's Licence, who had about 90 hours of experience, mostly in Cessna 152s. She was receiving type familiarisation training from a flight instructor. The instructor had some previous experience in a Jabiru J430 but not in a J400 before this training. They had flown together for 3 hours prior, but those flights had a third person occupying a rear seat. For the accident flight, only the front seats were occupied.
After one circuit to Runway 10, the owner flew a normal approach, maintaining 70 KIAS. At approximately 50 ft above aerodrome level, she reduced power aiming for 60 KIAS. The instructor suggested adding power, but the aircraft pitched nose-down abruptly. The descent rate increased, and before the instructor could intervene, the aircraft landed heavily in a nose-down attitude. As it slowed, the nose leg collapsed and the propeller struck the runway. The crew shut down systems and vacated without difficulty.
Commander's Comments
The instructor stated that prior to the owner's decision to purchase G-REAF, he had provided training in a microlight type he was more familiar with. When she bought the Jabiru, he agreed to provide familiarisation training to her and another pilot. He received advice from the aircraft's builder and previous owner, but only flew the aircraft himself when training began. He had 5 hours on type, all with three persons on board.
The instructor knew the recommended approach speed for the Jabiru J400 was 65 KIAS, but the builder had advised targeting 70 KIAS and keeping power above idle during landing to maintain elevator authority, as reduced propeller wash could affect control. The builder also noted that variations in payload significantly affect the centre of gravity (CG), which moves forward with only front seats occupied. The instructor and owner checked the weight and balance schedule and found the CG acceptable for two occupants.
The builder's written notes recommended: trim full aft, a late final speed of 65 kts, caution that speed is critical as the aircraft loses lift fast if speed drops, and to keep a little power on during round-out for elevator authority.
The instructor believed that pilots transitioning from conventional general aviation trainers could take longer to adjust to lighter aircraft like the Jabiru. He was surprised when the owner reduced power to near idle and the aircraft pitched nose-down. He considered that the airspeed indicator (ASI) might have over-read and the aircraft may have stalled, given the documented stall speed of 45 KIAS in landing configuration.
LAA Assessment
The Light Aircraft Association (LAA), which administered the Permit to Fly, offered several observations. The Type Acceptance Data Sheet (TADS) for the Jabiru J400 notes that handling is significantly affected by loading, especially rear seat loading, and recommends careful weight and balance checks.
Prior to this flight, the instructor and owner had only flown with three people on board. The LAA stated that the instructor should have appreciated how far forward the CG moved with two front occupants, accentuating the nose-down pitch when power was reduced. It was the instructor's first flight in this configuration, and he was surprised by the abrupt pitch-down. The LAA does not believe a stall occurred, but acknowledged that ASI accuracy in this class of aircraft is variable and intended to ensure the ASI is re-calibrated during rebuild.
The LAA encourages flight instructors to be conversant with the aircraft they train in; if inexperienced on type, they should fly with an experienced pilot first. If that was not possible, the instructor could have explored handling characteristics at a safe altitude, including slow flight and stalls in landing configuration, cross-checking the ASI with a stall warner or GPS data.
There are 25 Jabiru J400s administered by the LAA, all built from kits, so build quality and handling can vary. Pilots are advised to gain familiarity with individual machines. The LAA also noted that light aircraft like this, where payload accounts for a large percentage of total weight, have handling characteristics akin to microlights when lightly loaded, and that the nose landing gear systems in this class are generally less robust than those on classical trainers like Piper PA-28s or Cessna 152s.