iPhone automation using selenium webdriver,java,appium and webkit proxy: Not able to execute more than 1 testcase

Question

I am working on iPhone automation using selenium webdriver, appium & ios webkit debug proxy.

Configurations:
OS X Version 10.11.2
Appium 1.3.5
Xcode: 7.2
Device: iPhone 6[9.2]

I have installed safariLauncher app in iPhone using Xcode.

Steps:

1. I launched appium through terminal.
2. Cmd: Appium &
3. Then launched ios-webkit-debug-proxy.
4. Cmd: ./bin/ios-webkit-debug-proxy-launcher.js -c [device udid]:27753 -d

I launch appium & webkit server every time before starting any test case execution. Only the first test case works fine and 2nd test case onward run into below error in appium log:

code error: Failed to start an Appium session, err was: Error: Instruments crashed on startup
info: [debug] Error: Instruments crashed on startup
    at Instruments.onInstrumentsExit (/usr/local/lib/node_modules/appium/node_modules/appium-instruments/lib/instruments.js:389:31)
    at null.<anonymous> (/usr/local/lib/node_modules/appium/node_modules/appium-instruments/lib/instruments.js:308:12)
    at emitTwo (events.js:87:13)
    at ChildProcess.emit (events.js:172:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12)
info: [debug] Responding to client with error: {"status":33,"value":{"message":"A new session could not be created. (Original error: Instruments crashed on startup)","origValue":"Instruments crashed on startup"},"sessionId":null}
info: <-- POST /wd/hub/session 500 153251.340 ms - 182

Please suggest any solution.