Introduction
On 26 August 2021 at 0940 UTC, a de Havilland DH82A Tiger Moth (registration G-ANMO, serial number 3255, year of manufacture 1935) was conducting a training flight at Headcorn Aerodrome, Kent. The aircraft was operated under the operator's training organisation approval. Both occupants were instructors for the operator; the pilot in the rear cockpit was the pilot flying (PF). The purpose of the flight was to teach the PF to take off and land on the unlicensed grass strip Runway 03 (269 m long). The instructor occupied the front cockpit.
History of the Flight
Before the flight, the instructor and PF briefed the landing technique for about 15 minutes. The instructor described a technique: cross the trees at 50–60 ft and 50 kt, close the throttle when clear of the trees while easing the stick forward to maintain speed, then flare for a three-point landing at the intersection of Runways 10/28 and 03/21. They planned to go around from the first approach to allow the PF to familiarise with the unusual approach and foreshortened view.
In the front cockpit, the altimeter and airspeed indicator (ASI) were unserviceable. The PF's rear cockpit instruments were serviceable. The aircraft had a strut-mounted spring-operated ASI. The instructor sat on a parachute (not the taller cushion he was used to) and had his head to one side, which compromised his view of the approach and the strut-mounted ASI. The PF knew the front ASI was unserviceable but believed the instructor used the strut-mounted ASI; he was unaware the instructor could not see it well.
On the first approach, the instructor told the PF the aircraft was too high and instructed him to slip off height. The PF felt uncomfortable with the resulting low altitude but assumed it was correct. The go-around appeared acceptable to the instructor, but he was unaware of the speeds flown. During downwind, the instructor commented on the initial high approach but did not discuss airspeed.
For the second approach, the PF again sideslipped on instruction to lose height and checked his instruments, noting 300 ft aal at 50 kt. As the aircraft neared the trees, airspeed decayed to near stalling speed. The PF felt the aircraft sinking and applied full power. The instructor had not noticed the low and slow condition. The aircraft started to buffet (approaching stall), and the instructor took control just as the left wingtip hit a tree and the tailskid caught a power line atop wooden pylons. The aircraft pitched down, struck the ground on the undercarriage and nose, and then toppled onto its back. Both pilots, wearing full harness and helmets, were uninjured apart from a few scratches and were assisted from the aircraft by witnesses and airport fire service.
Pilot Assessments
The instructor stated he was complacent, having previously checked out the PF without concern. He noted that had the front cockpit ASI been serviceable and his seating position more normal, the accident would probably have been avoided. The PF felt the briefing could have been more thorough given his lack of experience on Runway 03, and he did not feel comfortable with the wind conditions that favoured Runway 28. In hindsight, he realised he should have expressed his concerns and perhaps rescheduled, rather than feeling pressured by the instructor's time constraints. After the first go-around, he felt the approach was wrong and that the instructor's comments downwind did not match his own assessment. He thought he should have handed control to the instructor or landed on Runway 28.
Discussion
Both pilots failed to notice they were too slow on the approach until the aircraft started to stall. The PF focused on the landing point and stopped monitoring his ASI; he relied on the instructor to call out speed and position errors. The instructor was unaware of this reliance, his view was compromised by his seating position, and he had no serviceable altimeter or ASI in his cockpit, so he could not monitor the approach effectively. The instrument unserviceabilities and compromised view were evident before the flight, presenting an opportunity to reschedule. The instructor was also unaware of the PF's concerns about the flight, which the PF later stated he should have voiced. As a result, opportunities were lost, both on the ground and in the air, to discuss these matters before commencing or continuing the instructional flight.
A Qualified Flying Instructor consulted by the AAIB advised that the approach is challenging but not difficult, and recommended that pilots new to Runway 03 come in high rather than under power to avoid losing sight of the trees, and aim to land as they cross the main runway 10/28.
Damage
The accident caused damage to the landing gear, propeller, wings, and fuselage.