# No elevon servo response after transition switch is on in the first VTOL test **URL:** \ **Category:** PX4 Autopilot\ **Created:** [April 16, 2018, 4:28pm UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386 "2018-04-16T16:28:55Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![bigbellmercy](https://discuss.px4.io/user_avatar/discuss.px4.io/bigbellmercy/32/6053_2.png) [@bigbellmercy](https://discuss.px4.io/u/bigbellmercy)\ **Post date:** [April 16, 2018, 4:28pm UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/1 "2018-04-16T16:28:55Z")
Hi, I’m testing VTOL software for the first time using quadcopter with generic quad delta airframe setting before using real VTOL drone. The problem is that after switching on the transition switch the elevon servo outputs do not respond and they are fixed to 1500 us in Analyzer of QGroundControl and pusher servo output seems not output at all. Airspeed sensor was installed, calibrated and enabled by parameter settings. What is the reason? Environments: PX4 v1.7.3 in Pixhawk2.1, QGC v3.3.1 ---
**Author:** ![rollys](https://discuss.px4.io/user_avatar/discuss.px4.io/rollys/32/2081_2.png) [@rollys](https://discuss.px4.io/u/rollys)\ **Post date:** [April 17, 2018, 1:25am UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/2 "2018-04-17T01:25:21Z")
Do you have a safety switch (push button) installed? if you do, you need to press that first. If you don’t, you need to disable it from being checked during bootup. Good luck. ---
**Author:** ![bigbellmercy](https://discuss.px4.io/user_avatar/discuss.px4.io/bigbellmercy/32/6053_2.png) [@bigbellmercy](https://discuss.px4.io/u/bigbellmercy)\ **Post date:** [April 17, 2018, 1:39am UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/3 "2018-04-17T01:39:59Z")
Yes, I installed a safety switch and pressed it before test. I am doubting the QuadChute function. Thanks rollys ---
**Author:** ![bigbellmercy](https://discuss.px4.io/user_avatar/discuss.px4.io/bigbellmercy/32/6053_2.png) [@bigbellmercy](https://discuss.px4.io/u/bigbellmercy)\ **Post date:** [April 17, 2018, 5:43am UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/4 "2018-04-17T05:43:15Z")
The problem disappeared after changing the airframe type from ‘generic quad delta VTOL’ to ‘DeltaQuad’. So the problem has been resolved by airframe change though I don’t know the reason of the problem. By default setting of all the parameters, with the Analyzer of QGC, the PWM channel ‘servo7\_raw’, maybe for forward thrust, outputs signal from 1000 to 2000 us when the transition switch switched on in the motor function check of drone on the ground. ---
**Author:** ![rollys](https://discuss.px4.io/user_avatar/discuss.px4.io/rollys/32/2081_2.png) [@rollys](https://discuss.px4.io/u/rollys)\ **Post date:** [April 19, 2018, 1:37am UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/5 "2018-04-19T01:37:17Z")
Now, just make sure that FW\_ARSP\_MODE is enabled if you have an airspeed sensor. Good luck, ---
**Author:** ![DrDogMeat](https://discuss.px4.io/letter_avatar_proxy/v4/letter/d/85e7bf/32.png) [@DrDogMeat](https://discuss.px4.io/u/DrDogMeat)\ **Post date:** [August 2, 2018, 1:51pm UTC](https://discuss.px4.io/t/no-elevon-servo-response-after-transition-switch-is-on-in-the-first-vtol-test/6386/6 "2018-08-02T13:51:15Z")
I am having the exact same problem. with both 1.7.3, and now 1.8.0. Where the elevons will work fine in MC mode but lock to 1500 pwm in FW mode. tried diabling safty switch blowing a fan in to the Pitot, also enabling and disabling airspeed blend and trans speeds. nothing works. I have an X8 using a custom mixer file. VT\_type = tilit rotor, with the airframe type an E-Flight Convergence. Anyone have any ideas? my mixer file is(if that helps)(M1,M2,M3,RearTilt,RightTilt,LeftTilt,Elevon1,Elevon2): R: 3y 10000 10000 10000 0 M: 1 O: 10000 10000 0 -10000 10000 S: 1 4 0 -20000 10000 -10000 10000 M: 2 O: 10000 10000 0 -10000 10000 S: 1 4 0 -20000 10000 -10000 10000 S: 0 2 8000 8000 0 -10000 10000 M: 2 O: 10000 10000 0 -10000 10000 S: 1 4 0 -20000 10000 -10000 10000 S: 0 2 -8000 -8000 0 -10000 10000 M: 2 O: 10000 10000 0 -10000 10000 S: 0 0 9000 9000 0 -10000 10000 S: 0 1 7000 7000 0 -10000 10000 M: 2 O: 10000 10000 0 -10000 10000 S: 0 0 9000 9000 0 -10000 10000 S: 0 1 -7000 -7000 0 -10000 10000