Aircraft window heat design causes distortions due to design and placement of heating elements

Attributes
ACN	100431
Time
Date	198812
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : lax
State Reference	CA
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : lax tower : lax
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport
Navigation In Use	Other
Flight Phase	descent : approach descent other other
Route In Use	approach : visual arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : cfi
Experience	flight time last 90 days : 140 flight time total : 2900 flight time type : 250
ASRS Report	100431
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other other

Narrative:

This situation is a recurrent problem I have noticed, along with many other pilots, concerning the medium large transport heating elements for the a and B windscreens. The design of these heating elements and windscreens results in several filament lines running vertically in the windscreens. The most serious problem I have noticed is on descent over a lot of ground lights like la. As you visually focus you eyes at a distance to acquire traffic if it or any ground lights pass through the vertical heating element distortions my eyes end up focusing to the windscreen causing me to loose the visual on previous acquired traffic. This problem is evident in the day time too, but to a lessor degree. I have also noticed that on CAT ii approachs, with ALS light intensity high, as the lights pass through the vertical distortions I have had a slight increase in sensations of vertigo. I feel, as many other of my fellow medium large transport pilots do that, although we can live with the handicap of these windscreens a situation may arise like air carrier in san diego where traffic is lost because of this windscreen.

Original NASA ASRS Text

Title: ACFT WINDOW HEAT DESIGN CAUSES DISTORTIONS DUE TO DESIGN AND PLACEMENT OF HEATING ELEMENTS

Narrative: THIS SITUATION IS A RECURRENT PROBLEM I HAVE NOTICED, ALONG WITH MANY OTHER PLTS, CONCERNING THE MLG HEATING ELEMENTS FOR THE A AND B WINDSCREENS. THE DESIGN OF THESE HEATING ELEMENTS AND WINDSCREENS RESULTS IN SEVERAL FILAMENT LINES RUNNING VERTICALLY IN THE WINDSCREENS. THE MOST SERIOUS PROBLEM I HAVE NOTICED IS ON DSCNT OVER A LOT OF GND LIGHTS LIKE LA. AS YOU VISUALLY FOCUS YOU EYES AT A DISTANCE TO ACQUIRE TFC IF IT OR ANY GND LIGHTS PASS THROUGH THE VERTICAL HEATING ELEMENT DISTORTIONS MY EYES END UP FOCUSING TO THE WINDSCREEN CAUSING ME TO LOOSE THE VISUAL ON PREVIOUS ACQUIRED TFC. THIS PROBLEM IS EVIDENT IN THE DAY TIME TOO, BUT TO A LESSOR DEGREE. I HAVE ALSO NOTICED THAT ON CAT II APCHS, WITH ALS LIGHT INTENSITY HIGH, AS THE LIGHTS PASS THROUGH THE VERTICAL DISTORTIONS I HAVE HAD A SLIGHT INCREASE IN SENSATIONS OF VERTIGO. I FEEL, AS MANY OTHER OF MY FELLOW MLG PLTS DO THAT, ALTHOUGH WE CAN LIVE WITH THE HANDICAP OF THESE WINDSCREENS A SITUATION MAY ARISE LIKE ACR IN SAN DIEGO WHERE TFC IS LOST BECAUSE OF THIS WINDSCREEN.

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.