De-ice fluid accumulated in an HS800 xp APU inlet low point baffle and subsequently entered the air ...

Attributes
ACN	779504
Time
Date	200803
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 1000
Environment
Flight Conditions	VMC
Weather Elements	Snow
Light	Daylight
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	general aviation : corporate
Make Model Name	BAe 125 Series 800
Operating Under FAR Part	Part 91
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : cfi pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 60 flight time total : 4900 flight time type : 2000
ASRS Report	779504
Events
Anomaly	aircraft equipment problem : critical other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : landed in emergency condition
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Smoke in the aircraft cabin resulting from de-ice fluid ingestion in to the aircraft's auxiliary power unit (APU). Event resulted in emergency return to the airport. Later research into the situation would reveal this is as a known problem by the aircraft manufacturer. De-ice fluid can pool within the air inlet duct of the APU which causes ingestion upon takeoff rotation. This effectively delays the result of the ingestion until takeoff. This hazard is not noted in aircraft's poh and has not been properly communicated to operations.callback conversation with reporter revealed the following information: the reporter stated that the amount of smoke in the cabin and flight station was surprisingly large. When it happened there was no doubt that the aircraft was returning in an emergency condition. Back at the airport; the crew did some research about the cause of this event and determined that the APU air inlet is designed so that a low point baffle allowed fluid to situation at the low point and be bypassed by the inlet air. However at rotation the fluid is sucked into the inlet and subsequently the air conditioning system. The reporter could find no reference to this design in any of the manuals available to him.

Original NASA ASRS Text

Title: DE-ICE FLUID ACCUMULATED IN AN HS800 XP APU INLET LOW POINT BAFFLE AND SUBSEQUENTLY ENTERED THE AIR CONDITIONING; FILLING THE CABIN WITH SMOKE ON TKOF ROTATION.

Narrative: SMOKE IN THE ACFT CABIN RESULTING FROM DE-ICE FLUID INGESTION IN TO THE ACFT'S AUXILIARY POWER UNIT (APU). EVENT RESULTED IN EMER RETURN TO THE ARPT. LATER RESEARCH INTO THE SITUATION WOULD REVEAL THIS IS AS A KNOWN PROBLEM BY THE ACFT MANUFACTURER. DE-ICE FLUID CAN POOL WITHIN THE AIR INLET DUCT OF THE APU WHICH CAUSES INGESTION UPON TAKEOFF ROTATION. THIS EFFECTIVELY DELAYS THE RESULT OF THE INGESTION UNTIL TAKEOFF. THIS HAZARD IS NOT NOTED IN ACFT'S POH AND HAS NOT BEEN PROPERLY COMMUNICATED TO OPS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THE AMOUNT OF SMOKE IN THE CABIN AND FLT STATION WAS SURPRISINGLY LARGE. WHEN IT HAPPENED THERE WAS NO DOUBT THAT THE ACFT WAS RETURNING IN AN EMER CONDITION. BACK AT THE ARPT; THE CREW DID SOME RESEARCH ABOUT THE CAUSE OF THIS EVENT AND DETERMINED THAT THE APU AIR INLET IS DESIGNED SO THAT A LOW POINT BAFFLE ALLOWED FLUID TO SIT AT THE LOW POINT AND BE BYPASSED BY THE INLET AIR. HOWEVER AT ROTATION THE FLUID IS SUCKED INTO THE INLET AND SUBSEQUENTLY THE AIR CONDITIONING SYSTEM. THE RPTR COULD FIND NO REFERENCE TO THIS DESIGN IN ANY OF THE MANUALS AVAILABLE TO HIM.

Data retrieved from NASA's ASRS site as of May 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.

De-ice fluid accumulated in an HS800 xp APU inlet low point baffle and subsequently entered the air conditioning; filling the cabin with smoke on takeoff rotation.