Alleged situation. No incident.

Attributes
ACN	133690
Time
Date	199001
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : tys
State Reference	TN
Altitude	msl bound lower : 5700 msl bound upper : 8800
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
ASRS Report	133690
Events
Independent Detector	other other : unspecified
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Chart Or Publication
Air Traffic Incident	other

Narrative:

It appears that there are conflicting MSA's displayed on different plates for knoxville. For example, plate 13-2 shows an MSA of 5700' on the 25 mi arc to the no F tys VOR. Plates 13-3 and 13-1 both show 8800' for the same 25 mi arc north of tys VOR. If the correct MSA is actually 8800' and we are in a situation where we use plate 13-2 to get MSA information, we could unsuspectingly operate the aircraft at an unsafe altitude. Graphically comparing the other plates where the MSA arcs are based on different navigation aids suggests that there could be a conflict there as well. It appears to me that a review of all the tys MSA's should be initiated.

Original NASA ASRS Text

Title: ALLEGED SITUATION. NO INCIDENT.

Narrative: IT APPEARS THAT THERE ARE CONFLICTING MSA'S DISPLAYED ON DIFFERENT PLATES FOR KNOXVILLE. FOR EXAMPLE, PLATE 13-2 SHOWS AN MSA OF 5700' ON THE 25 MI ARC TO THE NO F TYS VOR. PLATES 13-3 AND 13-1 BOTH SHOW 8800' FOR THE SAME 25 MI ARC N OF TYS VOR. IF THE CORRECT MSA IS ACTUALLY 8800' AND WE ARE IN A SITUATION WHERE WE USE PLATE 13-2 TO GET MSA INFO, WE COULD UNSUSPECTINGLY OPERATE THE ACFT AT AN UNSAFE ALT. GRAPHICALLY COMPARING THE OTHER PLATES WHERE THE MSA ARCS ARE BASED ON DIFFERENT NAVIGATION AIDS SUGGESTS THAT THERE COULD BE A CONFLICT THERE AS WELL. IT APPEARS TO ME THAT A REVIEW OF ALL THE TYS MSA'S SHOULD BE INITIATED.

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