diff --git a/dom/telephony/test/marionette/head.js b/dom/telephony/test/marionette/head.js
index 7ea0b87b485..93e8fd95a3e 100644
--- a/dom/telephony/test/marionette/head.js
+++ b/dom/telephony/test/marionette/head.js
@@ -55,6 +55,23 @@ let emulator = (function() {
  * Telephony related helper functions.
  */
 (function() {
+  /**
+   * @return Promise
+   */
+  function delay(ms) {
+    let deferred = Promise.defer();
+
+    let startTime = Date.now();
+    waitFor(function() {
+      deferred.resolve();
+    },function() {
+      let duration = Date.now() - startTime;
+      return (duration >= ms);
+    });
+
+    return deferred.promise;
+  }
+
   /**
    * @return Promise
    */
@@ -1016,6 +1033,7 @@ let emulator = (function() {
    * Public members.
    */
 
+  this.gDelay = delay;
   this.gCheckInitialState = checkInitialState;
   this.gClearCalls = clearCalls;
   this.gOutCallStrPool = outCallStrPool;
diff --git a/dom/telephony/test/marionette/test_outgoing_emergency_in_airplane_mode.js b/dom/telephony/test/marionette/test_outgoing_emergency_in_airplane_mode.js
index 67f9d7de514..d38654caed2 100644
--- a/dom/telephony/test/marionette/test_outgoing_emergency_in_airplane_mode.js
+++ b/dom/telephony/test/marionette/test_outgoing_emergency_in_airplane_mode.js
@@ -34,6 +34,7 @@ startTestWithPermissions(['mobileconnection'], function() {
     .then(() => gDial("112"))
     .then(call => { outCall = call; })
     .then(() => gRemoteAnswer(outCall))
+    .then(() => gDelay(1000))  // See Bug 1018051 for the purpose of the delay.
     .then(() => gRemoteHangUp(outCall))
     .then(null, () => {
       ok(false, "promise rejects during test.");