General aviation pilot described a near spacial disorientation event indicating ATC vectoring techni...

Narrative:

The report relates ATC instructions which may contribute to a spatial disorientation. I was ferrying an aircraft from ZZZ to ZZZ1 with a stop at ZZZ2. We were high for weather (FL210) as we crossed ZZZ3. We expedited the descent for the ILS approach at ZZZ2. It became apparent were going to be too high and the controller queried whether we wanted vectors to give us more time to descend. We advised we would and he gave us a 90 degree turn to the left. Approximately 30 seconds later he gave us a 180 degree turn to the right. As I will explain below; I was alert to the possibility of a spatial disorientation scenario and as I commanded the autopilot for the 180 degree turn while IMC and in a steep descent; I did in-fact experience disorientation; as did my pilot wife in the right seat. I also brief accidents and I had just finished a presentation involving an accident. This double fatal accident started with the aircraft on final approach at high speed overtaking a slower aircraft on an ILS approach. The controller issued descent instructions and a spacing vector; 90 left; followed by a 180 right. The pilot was in IMC and as he started the 180 degree right turn back to the final approach course; he lost control and crashed. Based on reports; the aircraft achieved a descent rate of over 5000 FPM just prior to impact which; in my opinion; could only have happened if the aircraft rolled inverted. I've been flying for nearly 30-years and these two episodes are the only time I've ever encountered a 90/180 vector. Normally for spacing; you get a racetrack or square pattern; i.e. 3 90 degree turns in the same direction. I must assume this technique is being taught in controller training; probably more recently; to controllers who are not familiar with the effects of spatial disorientation or the conditions which are conducive to creating it. My recommendation is that this information be disseminated to the controller population and that the practice of 90/180 be abandoned for less conducive techniques.

Original NASA ASRS Text

Title: General Aviation pilot described a near spacial disorientation event indicating ATC vectoring technique/s were a contributing factor both in this event and in a prior fatal accident.

Narrative: The report relates ATC instructions which may contribute to a spatial disorientation. I was ferrying an aircraft from ZZZ to ZZZ1 with a stop at ZZZ2. We were high for weather (FL210) as we crossed ZZZ3. We expedited the descent for the ILS approach at ZZZ2. It became apparent were going to be too high and the controller queried whether we wanted vectors to give us more time to descend. We advised we would and he gave us a 90 degree turn to the left. Approximately 30 seconds later he gave us a 180 degree turn to the right. As I will explain below; I was alert to the possibility of a spatial disorientation scenario and as I commanded the autopilot for the 180 degree turn while IMC and in a steep descent; I did in-fact experience disorientation; as did my pilot wife in the right seat. I also brief accidents and I had just finished a presentation involving an accident. This double fatal accident started with the aircraft on final approach at high speed overtaking a slower aircraft on an ILS approach. The controller issued descent instructions and a spacing vector; 90 left; followed by a 180 right. The pilot was in IMC and as he started the 180 degree right turn back to the final approach course; he lost control and crashed. Based on reports; the aircraft achieved a descent rate of over 5000 FPM just prior to impact which; in my opinion; could only have happened if the aircraft rolled inverted. I've been flying for nearly 30-years and these two episodes are the only time I've ever encountered a 90/180 vector. Normally for spacing; you get a racetrack or square pattern; I.E. 3 90 degree turns in the same direction. I must assume this technique is being taught in controller training; probably more recently; to controllers who are not familiar with the effects of spatial disorientation or the conditions which are conducive to creating it. My recommendation is that this information be disseminated to the controller population and that the practice of 90/180 be abandoned for less conducive techniques.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	921134
Time
Date	201001
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	PA-46 Malibu/Malibu Mirage/Malibu Matrix
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Single Pilot
Qualification	Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 9500 Flight Crew Type 550
Events
Anomaly	ATC Issue All Types Flight Deck / Cabin / Aircraft Event Other / Unknown Inflight Event / Encounter Other / Unknown

General aviation pilot described a near spacial disorientation event indicating ATC vectoring technique/s were a contributing factor both in this event and in a prior fatal accident.