Narrative:

Tehachapi municipal (tsp) and mountain valley airport (L94) are both located in the tehachapi valley; ca; 2.2 [2.196] NM apart based on the FAA airport/facilities directory latitude/longitude information. L94 has parallel runways; 09L-27R and 09R-27L. Right traffic is prescribed for 27R and left traffic for 27L. Tsp has one runway; 29-11; with currently prescribed left traffic for 29 and right traffic for 11. L94 is a glider port and has extensive operations going on spring through fall months. Twin engine aircraft maintaining recommended safe airspeeds on downwind and base leg experience uncomfortable angles of bank when trying to split the distance difference [2.2 NM] between these airports; sometimes causing an overshoot of the turn to final depending on wind and atmospheric conditions. Additionally; executive/corporate jet aircraft up through category C fly into tsp. Research into the FAA website on traffic pattern establishment yields order jo 7400.2J; procedures for handling airspace matters; fig 6-3-11; traffic pattern airspace; which specifies distances for patterns by aircraft category. Even for category a aircraft; the prescribed offset from centerline distance of 1.25 NM has the right traffic for L94; 27R; and left traffic for tsp; 29; overlaying each other. The offset for category C aircraft of 2.25 NM would conflict both runway traffic patterns at L94. The aeronautical information manual indicates that traffic patterns should not overlay population areas [if possible]. The left/right traffic patterns of tsp now overlay the majority of the business area and a large percentage of the population area to include elementary and high schools; all on the south side of the runway. The north side of the runway is sparsely developed. While there is a terrain single point terrain hazard approximately mid-field on the north side; this could be relieved by increasing the traffic pattern altitude appropriately. The continued use of the left 29; right 11 traffic patterns at tsp constitute a hazard to air navigation of these two airports and possible ground population in an emergency event.

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Original NASA ASRS Text

Title: A pilot reported potential traffic conflicts between L94 Runway 9L/27R traffic which turned north bound and traffic on right downwind TSP Runway 11 and left downwind TSP Runway 29.

Narrative: Tehachapi Municipal (TSP) and Mountain Valley airport (L94) are both located in the Tehachapi Valley; CA; 2.2 [2.196] NM apart based on the FAA airport/facilities directory latitude/longitude information. L94 has parallel runways; 09L-27R and 09R-27L. Right traffic is prescribed for 27R and left traffic for 27L. TSP has one runway; 29-11; with currently prescribed left traffic for 29 and right traffic for 11. L94 is a glider port and has extensive operations going on spring through fall months. Twin engine aircraft maintaining recommended safe airspeeds on downwind and base leg experience uncomfortable angles of bank when trying to split the distance difference [2.2 NM] between these airports; sometimes causing an overshoot of the turn to final depending on wind and atmospheric conditions. Additionally; executive/corporate jet aircraft up through Category C fly into TSP. Research into the FAA website on traffic pattern establishment yields Order JO 7400.2J; Procedures for Handling Airspace Matters; FIG 6-3-11; traffic pattern airspace; which specifies distances for patterns by Aircraft Category. Even for Category A aircraft; the prescribed offset from centerline distance of 1.25 NM has the right traffic for L94; 27R; and left traffic for TSP; 29; overlaying each other. The offset for Category C aircraft of 2.25 NM would conflict both runway traffic patterns at L94. The Aeronautical Information Manual indicates that traffic patterns should not overlay population areas [if possible]. The left/right traffic patterns of TSP now overlay the majority of the business area and a large percentage of the population area to include elementary and high schools; all on the south side of the runway. The north side of the runway is sparsely developed. While there is a terrain single point terrain hazard approximately mid-field on the north side; this could be relieved by increasing the traffic pattern altitude appropriately. The continued use of the left 29; right 11 traffic patterns at TSP constitute a hazard to air navigation of these two airports and possible ground population in an emergency event.

Data retrieved from NASA's ASRS site as of July 2013 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.