A beech-95 travel air equipped with an auxilliary gas heater experiences an uncommanded uncomfortabl...

Attributes
ACN	763884
Time
Date	200711
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : zzz.bcstn
State Reference	US
Altitude	msl single value : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	general aviation : personal
Make Model Name	Travelair 95
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	other
Function	instruction : trainee
Qualification	pilot : instrument pilot : private pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 35 flight time total : 345
ASRS Report	763884
Person 2
Function	controller : approach
Events
Anomaly	aircraft equipment problem : critical other anomaly non adherence : company policies
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed as precaution
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Finishing up an me check ride; the temperature in the aircraft began to rise; uncomfortably so. After checking the heater; which was not operating at the time; we could not surmise the reason for the temperature rise. Shortly thereafter smoke began to appear in the cabin. All systems were checked and nothing seemed out of normal range. ZZZ approach was contacted and advised that we were landing immediately. (An emergency was never declared with approach.) ZZZ1 was eleven miles away; so we decided for ZZZ2. The field was basically right below us on ZZZ3. The heat was rising and the smoke was getting worse and we made the field within five minutes. After landing and giving close examination to the heater located in the nose wheel well we concluded that the heater had malfunctioned. Significant black smoke was located in and around the exhaust and fwd landing gear door.callback conversation with reporter revealed the following information: reporter stated the heat and smoke were significant and hot. He was told by maintenance a full blown fire would have erupted in the nose compartment had he not landed the aircraft as quickly as he did. Appears there were two safety switches that had failed. Whether they were the overheat switches or the combustion pressure switch is unclear at this time. This was a janitrol combustion type cabin heater. This aircraft is a 1959 model. He does not know if the heater is the original unit; a rebuilt or upgraded model. The heater had not been in use for at least 4-5 days previous and was not operating at that time. Whatever initiated combustion in the heater was not commanded by him. Reporter also stated there was a lot of black soot inside the nose wheel well and on the external side of the nose section. This aircraft does not have any overheat or fire warning systems associated with the combustion heater.

Original NASA ASRS Text

Title: A BEECH-95 TRAVEL AIR EQUIPPED WITH AN AUXILLIARY GAS HEATER EXPERIENCES AN UNCOMMANDED UNCOMFORTABLE RISE IN CABIN TEMPERATURE WITH SMOKE; EVEN THOUGH THE HEATER WAS NOT TURNED ON. THE PLT EXECUTED AN IMMEDIATE EMER LNDG.

Narrative: FINISHING UP AN ME CHK RIDE; THE TEMPERATURE IN THE ACFT BEGAN TO RISE; UNCOMFORTABLY SO. AFTER CHKING THE HEATER; WHICH WAS NOT OPERATING AT THE TIME; WE COULD NOT SURMISE THE REASON FOR THE TEMP RISE. SHORTLY THEREAFTER SMOKE BEGAN TO APPEAR IN THE CABIN. ALL SYSTEMS WERE CHKED AND NOTHING SEEMED OUT OF NORMAL RANGE. ZZZ APCH WAS CONTACTED AND ADVISED THAT WE WERE LNDG IMMEDIATELY. (AN EMERGENCY WAS NEVER DECLARED WITH APPROACH.) ZZZ1 WAS ELEVEN MILES AWAY; SO WE DECIDED FOR ZZZ2. THE FIELD WAS BASICALLY RIGHT BELOW US ON ZZZ3. THE HEAT WAS RISING AND THE SMOKE WAS GETTING WORSE AND WE MADE THE FIELD WITHIN FIVE MINUTES. AFTER LNDG AND GIVING CLOSE EXAMINATION TO THE HEATER LOCATED IN THE NOSE WHEEL WELL WE CONCLUDED THAT THE HEATER HAD MALFUNCTIONED. SIGNIFICANT BLACK SMOKE WAS LOCATED IN AND AROUND THE EXHAUST AND FWD LNDG GEAR DOOR.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE HEAT AND SMOKE WERE SIGNIFICANT AND HOT. HE WAS TOLD BY MAINT A FULL BLOWN FIRE WOULD HAVE ERUPTED IN THE NOSE COMPARTMENT HAD HE NOT LANDED THE ACFT AS QUICKLY AS HE DID. APPEARS THERE WERE TWO SAFETY SWITCHES THAT HAD FAILED. WHETHER THEY WERE THE OVERHEAT SWITCHES OR THE COMBUSTION PRESSURE SWITCH IS UNCLEAR AT THIS TIME. THIS WAS A JANITROL COMBUSTION TYPE CABIN HEATER. THIS ACFT IS A 1959 MODEL. HE DOES NOT KNOW IF THE HEATER IS THE ORIGINAL UNIT; A REBUILT OR UPGRADED MODEL. THE HEATER HAD NOT BEEN IN USE FOR AT LEAST 4-5 DAYS PREVIOUS AND WAS NOT OPERATING AT THAT TIME. WHATEVER INITIATED COMBUSTION IN THE HEATER WAS NOT COMMANDED BY HIM. RPTR ALSO STATED THERE WAS A LOT OF BLACK SOOT INSIDE THE NOSE WHEEL WELL AND ON THE EXTERNAL SIDE OF THE NOSE SECTION. THIS ACFT DOES NOT HAVE ANY OVERHEAT OR FIRE WARNING SYSTEMS ASSOCIATED WITH THE COMBUSTION HEATER.

Data retrieved from NASA's ASRS site as of January 2009 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.

A beech-95 travel air equipped with an auxilliary gas heater experiences an uncommanded uncomfortable rise in cabin temperature with smoke; even though the heater was not turned on. The pilot executed an immediate emergency landing.