Gear up landing in small aircraft twin.

Attributes
ACN	132610
Time
Date	198912
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ccr
State Reference	CA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : mia
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 2 Eng, Retractable Gear
Flight Phase	landing other
Flight Plan	None
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : commercial pilot : instrument pilot : cfi
Experience	flight time last 90 days : 150 flight time total : 1600 flight time type : 100
ASRS Report	132610
Person 2
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : private
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other other : unspecified cockpit
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Training for private MEL rating. Simulated single engine approach and landing. Student and instrument using headphones and intercom. Student forgot to lower landing gear and did not hear gear warning horn due to noise reduction characteristics of headphones. Instrument did not hear either. Removed headphones to verify horn operative, and instructed student to lower landing gear. I always use an intercom and headphones for good communication while instructing. I have noticed similar problem with still warning horns before. The use of quality noise reducing headphones can render warning horns ineffective. The situation will be even worse with the new noise cancelling headphones. I recommend the NTSB/FAA consider the following requirements: 1) warning horn sound electrically connected to phone jacks, so that any pilot connecting headphones to the aircraft system will hear warning horn sound through the headphones. 2) prohibit use of headphones in aircraft unless connected to such a system. (This is to overcome problem or intercom used for training west/O being connected to aircraft system.) an aircraft with inoperative warning horn is not airworthy. Need to stop use of headphones causing essentially the same situation.

Original NASA ASRS Text

Title: GEAR UP LNDG IN SMA TWIN.

Narrative: TRNING FOR PVT MEL RATING. SIMULATED SINGLE ENG APCH AND LNDG. STUDENT AND INSTR USING HEADPHONES AND INTERCOM. STUDENT FORGOT TO LOWER LNDG GEAR AND DID NOT HEAR GEAR WARNING HORN DUE TO NOISE REDUCTION CHARACTERISTICS OF HEADPHONES. INSTR DID NOT HEAR EITHER. REMOVED HEADPHONES TO VERIFY HORN OPERATIVE, AND INSTRUCTED STUDENT TO LOWER LNDG GEAR. I ALWAYS USE AN INTERCOM AND HEADPHONES FOR GOOD COM WHILE INSTRUCTING. I HAVE NOTICED SIMILAR PROB WITH STILL WARNING HORNS BEFORE. THE USE OF QUALITY NOISE REDUCING HEADPHONES CAN RENDER WARNING HORNS INEFFECTIVE. THE SITUATION WILL BE EVEN WORSE WITH THE NEW NOISE CANCELLING HEADPHONES. I RECOMMEND THE NTSB/FAA CONSIDER THE FOLLOWING REQUIREMENTS: 1) WARNING HORN SOUND ELECTRICALLY CONNECTED TO PHONE JACKS, SO THAT ANY PLT CONNECTING HEADPHONES TO THE ACFT SYS WILL HEAR WARNING HORN SOUND THROUGH THE HEADPHONES. 2) PROHIBIT USE OF HEADPHONES IN ACFT UNLESS CONNECTED TO SUCH A SYS. (THIS IS TO OVERCOME PROB OR INTERCOM USED FOR TRNING W/O BEING CONNECTED TO ACFT SYS.) AN ACFT WITH INOP WARNING HORN IS NOT AIRWORTHY. NEED TO STOP USE OF HEADPHONES CAUSING ESSENTIALLY THE SAME SITUATION.

Data retrieved from NASA's ASRS site as of August 2007 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.