Date: 201905
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: DA62
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Takeoff / Launch
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: FBO
Reporter function: Instructor
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Time Pressure; Situational Awareness
Second reporter function: Trainee; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Ground Excursion Runway
Detector: Person Flight Crew
When detected: Other Takeoff
Result: Aircraft Aircraft Damaged; Flight Crew Took Evasive Action; Flight Crew Rejected Takeoff
Contributing factors: Human Factors; Aircraft
Primary problem: Ambiguous

Narrative: I was an instructor in a multi-engine aircraft flown by a properly rated student who has about 12 hours flight time in the plane. The incident was a high-speed aborted takeoff that led to a runway overrun through the stopway. In the process; the left tire blew. Other than the tire; no damage was noted to the aircraft or airport property. The runway was closed for [a few] hours while the tire was changed so the aircraft could be towed.We briefed the departure and knew the departure runway was 3900 feet long and that our accelerate/stop distance was 3400 feet. Our CG was at the forward end of the permissible range. Also; a flaps-up takeoff was selected. Upon reaching rotation speed; my student rotated and I felt the plane slowly come off the ground and into ground effect. I sensed my student try to gain airspeed by lowering the nose and he then pulled up again and did not get the response he anticipated. He elected to abort the takeoff; brought the throttle to idle; and once the plane was back on the ground; he applied max braking. I believe there were two factors that led to the incident: 1) the flaps-up takeoff; although permitted according to the Airplane Flight Manual; provides a longer ground roll and increased the accelerate/stop distance. 2) The forward CG also leads to a longer takeoff roll and may have contributed to the lack of responsiveness my student felt. We discussed a takeoff with standard flaps; but my student mentioned that he was more comfortable with flaps-up in the event we lost an engine on the takeoff climb. I thought that was a reasonable position. However; we had the option of departing on Runway XY which is [longer]. Electing to depart from Runway XY would have greatly mitigated the risk of an overrun. Also; the aircraft was 400 pounds below max gross takeoff weight; so we also could have put more weight in the rear of the passenger area to move the CG aft and increase performance.


Second narrative: Aircraft was within CG; and we were 500 lbs+ under gross; accelerate stop distance was calculated to be 3400 ft. An instructor was on board; and we were in the same weight; CG; and aircraft configuration as a number of previous flights in this airframe that were uneventful. The aircraft was thoroughly pre-flighted; and a runup was conducted along with an available power check. The aircraft was configured for departure (trims to takeoff; boosts pumps on); with flaps selected in the up position. The instructor and I discussed this flap setting; and all of my departures in this aircraft (which is a twin engine aircraft) to date had been done flaps up for reasons of less drag should an engine fail at low altitude upon departure. We conducted a standard departure brief; including that if there was a problem on takeoff while the gear was still down and we had usable runway; I would cut the throttles and land the aircraft.Upon entering XXL after being cleared for takeoff; I lined up and with the brakes applied; powered the aircraft to full throttle; and checked that it was making full power with all instruments normal. Once we reached full power; I released the brakes and began the takeoff roll. The aircraft felt 'normal' in terms of rate of acceleration vs position down the runway. Airspeed was alive and cross checked at 50kts. Things felt normal until I went to rotate at 82 kts (Vr in 80); and as I rotated the aircraft controls felt more sluggish than normal; and the aircraft sort of mushed in ground effect without a real positive rate of climb. At this point I released back pressure slightly to allow the aircraft to accelerate further; to see if response/performance would improve; and at the same time cross-checked my engine gauges (still both at 100% power) and backup airspeed indicator (checks). At this point I saw 90kts (Vy is 89...) indicated and gave the stick another authoritative pull; and the aircraft mushed again and still felt like it didn't want to climb. I made the immediate decision to abort the takeoff; we had approximately 1/3 of the runway remaining; and I cut the throttles to idle and did an immediate descent from about 15-20 feet AGL down to land. As soon as the mains hit I began applying brakes; with max braking being applied when the nosewheel touched down. I was able to maintain directional control under max braking; and as we approached the departure end of XXL (at an estimated 15-20 kts about 50 feet from the threshold); the left main tire blew; and I lost a large degree of stopping capability. I stood on the right rudder to keep us generally pointing straight and avoid a runway end identifier light that was to the left of the left engine prop; and we rolled about 50 feet onto the paved overrun beyond the threshold.Damage was limited to aircraft main tires (left blown; right blistered). No damage to the airport; and no injuries. The runway was closed while we awaited a tow.While I believe the actions taken were appropriate and the safest possible course of action given the circumstances at that time; I would/will do 3 things differently moving forward. The first is that ZZZ has a much longer runway; Runway XY; and while Ground/Tower Control prefers to have our training flights on XXL; I'm going to insist on using XY in the future for twin engine aircraft at this airport. That decision would have given us a lot more room to stop and avoid the overrun and damage to the aircraft tires. The second is that while takeoffs in the DA62 with no flaps is an AFM approved takeoff configuration; and is the configuration in which I have done all of the takeoffs I have done to date in this aircraft; I am going to in the future be selecting flap position one for more lift. The third is that my first inclination that something wasn't right was immediately after rotation; and I chose to spend a few precious seconds at 80-90 kts trying to confirm/deny what I felt was going on; when I should have just immediately shut it down.


Synopsis: DA62 Instructor and trainee reported a runway excursion after a rejected takeoff.