### [4910-13-~1

llJT1N() SYMOOL 

### AGENCY: Federal Aviation Administration (FAA), Department ofTransportation

above. This AD results from mandatory continuing airworthiness information (MeAl) SUMMARY: We are adopting anew airworthiness directive (AD) forthe products listed m 

### ACTION: Final rule; request forcomments. (DOT). Federal Aviation Administration

RlN 2120-AA64 Ainvorthiness Directives; Bombardier. Inc. Model DHC-8-400 Series Airplanes DEPARTMENT OF TRANSPORT AnON



# 0431 [Docket No. FAA-20l0-*****; Directorate Identifier 2010-N1\1-072-AD;



# IIA2.71- 

# -0':'-07 Amendment 39-"'1(,(***; AD 2010-**-**] 14 CFR Part 39

originated by an aviation authority of another country to identify and correct an unsafe ITIALSI,IG 

### condition on an aviation product. The MeAldescribes the unsafe condition as:



### *

## ** 1.Apotential freezing ofthe AOA [angle of attack] Vane Resolver 

## *

## **may restrict the dynamic behavior (lag) ofthe vane and could lead to apotential seize-up condition"at lower temperatures. This condition, ifnot corrected, may provide inaccurate ADA data to the Stall Protection System (SPS). lflAI.srsIG

'llTlNG H"'ElOL 

### 2. As aresult ofageing, the AOA vane heating element could degrade to a point where there is insufficient heat to prevent icebuild-up on the AOA vanes. The ice build-up may lead to achange inthe aerodynamic properties ofthe AOA vane and, under certain conditions, send inaccurate information to the SPS. This ageing condition cannot be detected by the aircraft ADA vane heater current monitor. 'llTING SYMllOL
ITIA.lSl'1G[4910-I3-P) 

### DEPARTMENT OFTRANSPORTATION Federal Aviation Administration 14 CFR Part 39 {lNCUlU'-o><C,;s ,~nSYMBOI. ANE-172 [Docket No. FAA-201O-**~**j Directorate Identifier 201O-NM-072-AD; Amendment 39-*****; AD 20**-**-**) RIN 2120-AA64 Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 

### Series Airplanes AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Final rule; request for comments. 

### SUMMARY: Weare adopting anewairworthiness directive (AD) forthe products liste 

## ANE~1570"()L above. This AD results from mandatory continuing airworthiness information (MeAl) 

### originated by 

### an aviation authority ofanother country toidentify and correct anunsafe condition onan aviation product. The MeAl 

### describes theunsafe condition as:



## ** *- 1. A potential freezing ofthe AOA [angle of attack] Vane Resolver, which may restrict the dynamic behavior (lag) ofthe vane and could lead to a potential seize-up condition at lower temperatures. This condition, if nol corrected, may provide inaccurate ADA data to the Stall Protection System (SPS). . 2. As a result of ageing, the 

### ADA vane heating element could degrade to a point where there is insufficient heat to prevent ice build-up on the ADA vanes. The ice build-up may lead to a change in the aerodynamic properties of the 

### ADA vane and, under certain conditions, send inaccurate information to the SPS. This ageing condition cannot be detected by the aircraft 

### ADA vane heater current monitor. 0\1"''''' SVMJlQL

J~TB

# ,

i i 1491~13-PI

DEPARTMENT OF TRANSPORT AnON Federal Aviation Administration



### 'IN<i'Y~""" SUMMAR Y: We are adopting anew airworthiness directive (AD) for the products liste ,\NE_17fI 14CPR Part 39 

### IDocket No. FAA-2010-h***; 

### Directorate Identifier 

### 201O-NM-072-AD; Amendment 39-*****; AD 2010~H_**1 RIN 2120~AA64 Airworthiness Directives; Bombardier, Inc. Model DHC-8-400 Series Airplanes AGENCY: Federal Aviation Administration (FAA), Department ofTransportation (DOT). ACTION: final rule; request forcomments.
above. This AD results from mandatory continuing airworthiness information (MeAl) originated by all aviation authority ofanother country to identify and correct an unsafe condirion on an aviation product. The MeAl describes the unsafe condition as·



## * "'.•I. /\ pOLenlial freezingofLhe ADA langlcorauaekj Vane Resolver '".•'"lllay restrict the dynamic belHlvior(lag) ofthe vane and could lead to apotential seize-up condition at lower temperatures. This condition, ifnol corrected, may provide inaccurate AOA data to the Stall Protection System (SPS). 2. As aresult ofageing, the AOA vane heating element could degrade lO a poinl when::tht::reis insufficient heat to prevent ice build-up on the AOA vanes. TIle ice build-up may lead to achange inthe aerodynamic properties ofthe ADA vane and, under certain conditions, send inaccurate information to the SPS. This ageing condition cannot be detected by the aircraft AOA vane heater current monitor. 

### -~"'''''"'

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