Two mooney pilots reported a gear up landing for unknown reasons.

Attributes
ACN	1420986
Time
Date	201701
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	M-20 J (201) / Allegro
Operating Under FAR Part	Part 91
Flight Phase	Landing
Component
Aircraft Component	Landing Gear
Person 1
Function	Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Commercial Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 200 Flight Crew Total 2950 Flight Crew Type 30
Person 2
Function	Pilot Flying
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 41 Flight Crew Total 259 Flight Crew Type 15
Events
Anomaly	Ground Event / Encounter Gear Up Landing

Narrative:

After completion of 3 non eventful landings the PIC set up on final approach for the last landing of the day. Everything was going perfect as did the previous landings; however; this time I started to hear something scrape the runway as the plane settled onto the surface. We both saw smoke in the cockpit as we slid to a stop; the PIC pulled the gear lever back up due to seeing smoke coming from the gear handle. I saw smoke coming from the mixture knob and advised him to pull the mixture and secure the aircraft by turning everything off. I quickly exited the airplane and checked for leaks or signs of fire. Then returned to the cockpit to contact tower on the radio. So as an observer I would like to add I didn't not hear the gear warning horn or see the bypass light illuminated on the dash panel. I believe the PIC took all appropriate measures to ensure the gear was down and locked.

Original NASA ASRS Text

Title: Two Mooney pilots reported a gear up landing for unknown reasons.

Narrative: After completion of 3 non eventful landings the PIC set up on final approach for the last landing of the day. Everything was going perfect as did the previous landings; however; this time I started to hear something scrape the runway as the plane settled onto the surface. We both saw smoke in the cockpit as we slid to a stop; the PIC pulled the gear lever back up due to seeing smoke coming from the gear handle. I saw smoke coming from the mixture knob and advised him to pull the mixture and secure the aircraft by turning everything off. I quickly exited the airplane and checked for leaks or signs of fire. Then returned to the cockpit to contact tower on the radio. So as an observer I would like to add I didn't not hear the gear warning horn or see the bypass light illuminated on the dash panel. I believe the PIC took all appropriate measures to ensure the gear was down and locked.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.