Need help with Descending Orbit Game Object (Plane Crashing)

I have a lot of the code done however I do not now how to get this to work properly. What I am doing is spawning in a cargo plane that I want to crash after so many seconds minimum and max seconds to randomly either begin the plane crash and when it does it goes from flying in a straight path to changing it to a angled descending orbit till it hits the ground with it to randomly decided clockwise or counterclockwise and adjust the game object to be angled at 20 or -20 degrees.

So basically it starts to crash leans to the side in a circular pattern descending to the ground until it hits the ground and dies basically.

I am also trying to display a message saying plane has started to crash which I have working but seems to be stuck in a loop when it happens.

Here is some of the code I already have done - currently it starts to descend and pitch towards the ground however I cant figure out from here how to make it orbit while descending and only queue the message once.

 private void FixedUpdate()
             {
                 if (entity.transform.position.y <= -5)
                 {
                     if (!isDying)
                         Die();
                     return;
                 }            
                 
                 
                 if (status == FlightStatus.Crashing)
                 {
                     crashTimeTaken = crashTimeTaken + UnityEngine.Time.deltaTime;
                     float single = Mathf.InverseLerp(0, crashTimeToTake, crashTimeTaken);
                     if (single < 1)
                     {
                         currentSpeed = speed - Mathf.Lerp(0, 10, single);
                         entity.transform.transform.eulerAngles = new Vector3(Mathf.Lerp(0, 15f, single), entity.transform.transform.eulerAngles.y, entity.transform.transform.eulerAngles.z);
                     }
 
                     entity.transform.position = Vector3.MoveTowards(entity.transform.position, entity.transform.position + (entity.transform.forward * 10), currentSpeed * UnityEngine.Time.deltaTime);
                     Rotate();
                 }
                 else
                 {
                     entity.transform.position = Vector3.MoveTowards(entity.transform.position, endPos, currentSpeed * UnityEngine.Time.deltaTime);
 
                     if (isDropPlane)
                     {
                         timeTaken = timeTaken + UnityEngine.Time.deltaTime;
                         entity.secondsTaken = timeTaken;
                         float single = Mathf.InverseLerp(0, timeToTake, timeTaken);
                         if (!hasDropped && single >= 0.5f)
                         {
                             hasDropped = true;
                             if (!Instance.FancyDrop || !isFancyDrop)
                             {
                                 BaseEntity drop = GameManager.server.CreateEntity(supply, entity.transform.position);
                                 drop.globalBroadcast = true;
                                 drop.Spawn();
                             }
                         }
                     }
                 }
                 entity.transform.hasChanged = true; 
             }
 
 private void RandomCrash()
             {
                 if (countdownTimer == 0 && status == FlightStatus.Crashing)
                     SendChatMessage("FailingMessage1", FlightNumber);
                 BeginCrash();            
             }    
 
             private void Rotate()
             {
                 xSpeed = 35;
                 zSpread = 500;
                 yOffset = 15;
                 if(rotateClockwise)
                 {
                     float x = -Mathf.Cos(timer) * xSpeed;
                     float z = Mathf.Sin(timer) * zSpread;
                     Vector3 pos = new Vector3(x, yOffset, z);
                     entity.transform.position = pos + centerPoint.position;                    
                 }
                 else
                 {
                     float x = Mathf.Cos(timer) * xSpeed;
                     float z = Mathf.Sin(timer) * zSpread;
                     Vector3 pos = new Vector3(x, yOffset, z);
                     entity.transform.position = pos + centerPoint.position; 
                 }
             }
 
  public void BeginCrash()
             {
                 endPos = new Vector3(endPos.x, 0, endPos.z);
                 status = FlightStatus.Crashing;
 
                 SmallExplosion();
                 AddFire();
             }
 
             private void BigExplosion()
             {
                 RunEffect(heliExplosion, null, entity.transform.position);
                 RunEffect(debris, null, entity.transform.position);
             }
 
             private void SmallExplosion()
             {
                 RunEffect(c4Explosion, null, entity.transform.position);
                 RunEffect(debris, null, entity.transform.position);
             }
 
             private void AddFire()
             {
                 if (engineFires == null)
                 {
                     engineFires = new FireBall[]
                     {
                         SpawnFireball(entity, new Vector3(-10, 6, 10), 600),
                         SpawnFireball(entity, new Vector3(10, 6, 10), 600)
                     };
                 }
             }
 
             private void Die()
             {
                 if (isDying)
                     return;
 
                 isDying = true;
                 BigExplosion();
 
                 InvokeHandler.Invoke(this, SmallExplosion, 0.25f);
                 InvokeHandler.Invoke(this, SmallExplosion, 0.5f);
                 InvokeHandler.Invoke(this, BigExplosion, 1.25f);
                 InvokeHandler.Invoke(this, SmallExplosion, 1.75f);
                 InvokeHandler.Invoke(this, BigExplosion, 2.25f);
 
                 Destroy(this, 2.5f);
             }