An sa-227 pilot mistook the 'west' in a naco airport chart longitude marking (81.52W) as a taxiway d...

Attributes
ACN	1158746
Time
Date	201403
Local Time Of Day	0601-1200
Place
Locale Reference	CLE.Airport
State Reference	OH
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	SA-227 AC Metro III
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Aero Charts
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 90 Flight Crew Total 3700 Flight Crew Type 250
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Ground Incursion Taxiway

Narrative:

I was parked at the FBO; off taxiway L2. I was given taxi instructions 'taxi to 24L via L2; left; west; hold short of 24L.' I looked at my naco airport diagram and misread it. On the bottom of the chart; there is a longitude marking of 81.52W. The 'west' made it appear that taxiway 'T' was taxiway 'west'.instead of making a right turn on taxiway left; I made a left turn on taxiway left and was proceeding to what I thought was taxiway west. Ground asked me if I was heading southwest; and I confirmed that I was. I was then told to turn around on pad 5 and taxi as previously instructed. There was no threat of an aircraft collision.I believe that having this longitude marking makes it easy to mistake taxiway 'T' for taxiway 'west' and should be relocated to another point on the chart. It is the same size and font as the rest of the taxiway labels.

Original NASA ASRS Text

Title: An SA-227 pilot mistook the 'W' in a NACO airport chart longitude marking (81.52W) as a taxiway designator at CLE and taxied southwest bound toward 6R after being cleared to runway 24L via Lima 2; Lima and Whiskey. The actual W taxiway is at the departure end of 24L.

Narrative: I was parked at the FBO; off Taxiway L2. I was given taxi instructions 'Taxi to 24L via L2; L; W; hold short of 24L.' I looked at my NACO airport diagram and misread it. On the bottom of the chart; there is a longitude marking of 81.52W. The 'W' made it appear that Taxiway 'T' was Taxiway 'W'.Instead of making a right turn on Taxiway L; I made a left turn on Taxiway L and was proceeding to what I thought was Taxiway W. Ground asked me if I was heading southwest; and I confirmed that I was. I was then told to turn around on Pad 5 and taxi as previously instructed. There was no threat of an aircraft collision.I believe that having this longitude marking makes it easy to mistake Taxiway 'T' for Taxiway 'W' and should be relocated to another point on the chart. It is the same size and font as the rest of the taxiway labels.

Data retrieved from NASA's ASRS site 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.

An sa-227 pilot mistook the 'west' in a naco airport chart longitude marking (81.52W) as a taxiway designator at cle and taxied southwest bound toward 6R after being cleared to runway 24L via lima 2; lima and whiskey. The actual west taxiway is at the departure end of 24L.