Date: 202109
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Haze / Smoke; 7
Light: Daylight
Aircraft: Small Aircraft; Low Wing; 2 Eng; Retractable Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
Airspace: Class E ZZZ
ATC / advisory: CTAF ZZZ
Second aircraft: Skyhawk 172/Cutlass 172
Aircraft component: Gear Extend/Retract Mechanism
Component problem: Improperly Operated
Reporter organization: FBO
Reporter function: Instructor; Pilot Not Flying; DPE
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown; Training / Qualification
Second reporter function: Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Gear Up Landing
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Human Factors

Narrative: On Date; I conducted a multi-engine commercial examination in a [small two-engine aircraft]. While conducting a simulated engine failure single-engine ILS approach to Runway XX at ZZZ; ATC; (i.e.; ZZZ Approach Control); vectored the applicant onto final. Once laterally established on the approach; ATC switched the applicant over to the common traffic advisory frequency. ATC provided no further traffic advisories or alertsThe applicant then switched to the advisory frequency and announced his position as a five (5) mile final to Runway XX. Aircraft Y then announced downwind for Runway XY. I then told the applicant that in the event of go-around; both engines were available. The applicant continued while I searched for traffic in haze and seven mile visibility. The applicant reported a three (3) mile final. I continued to scan for Aircraft Y. I told the applicant that I had not spotted the traffic and then radioed that we were on a one and one-half (1 and ½) mile final. In response; Aircraft Y stated they had us in sight. I asked them to go-around. Instead; they called they were turning final for Runway XY. When the applicant called one hundred feet (100') above minimums; I spotted Aircraft Y. At that time; I told the applicant the runway was in sight and the applicant removed his foggles. I pointed the traffic to the applicant at one to two o'clock and less than a quarter (1/4) mile and again asked Aircraft Y to execute a go-around; which he then did as he flew over the top of us at the intersection of Runway XX and Runway XY. As the applicant flared to land; the tail struck the pavement. Only then did I realize that the applicant failed to complete the before landing checklist; by extending the gear; which I; in turn; failed to observe.


Second narrative: On Date I was taking a multi-engine commercial check ride with Designated Pilot Examiner [DPE] Name. I was the pilot in command for the flight. After flying the maneuvers we set up for the ILS XX into ZZZ. We had a simulated engine failure during the approach. ZZZ approach approved frequency change and gave no traffic advisories. I made a 5 mile final call on the CTAF followed by a 3 mile final call. During a 2 mile final Aircraft Y made a final call for Runway XY. I still had the foggles on and the [DPE] was searching for the traffic. I announced we reached the DA; and at that time name told me to remove the foggles. He was still searching for the traffic and talking to the other aircraft. Aircraft Y announced they would go around and I continued my approach inbound for Runway XX. With all the confusion and concerns of a mid-air collision i failed to complete the before landing check. It wasn't realized that the gear was retracted until the tail struck.Distraction and pressure were two major human factors that contributed to this incident. The other aircraft distracted me from completing the before landing check. In addition; the pressure of flying the approach and completing the maneuver within standards played a role.


Synopsis: Flight crew reported distractions from a near mid air collision resulted in the landing check list not being performed and a gear up landing.