diff -u -r1.5 -r1.6
--- TrackHelixExtrapolator.java	9 Oct 2008 21:38:28 -0000	1.5
+++ TrackHelixExtrapolator.java	27 Oct 2008 18:48:20 -0000	1.6
@@ -98,7 +98,18 @@

 		    double rBarrel = Math.sqrt(interceptBarrel.x()*interceptBarrel.x() + interceptBarrel.y()*interceptBarrel.y());
 		    double zEndcap = interceptEndcap.z();
 		    double zBarrel = interceptBarrel.z();

-		    throw new AssertionError("Track hits endcap THEN barrel -- this doesn't make sense!\nEndcap intercept at alpha="+alphaEndcap+" has r="+rEndcap+", z="+zEndcap+"\nBarrel intercept at alpha="+alphaBarrel+" has r="+rBarrel+", z="+zBarrel);

+		    System.out.println(this.getClass().getName()+": Track extrapolation failure: Track hits endcap THEN barrel -- this doesn't make sense!");
+		    System.out.println("   Endcap intercept at alpha="+alphaEndcap+" has r="+rEndcap+", z="+zEndcap);
+		    System.out.println("   Barrel intercept at alpha="+alphaBarrel+" has r="+rBarrel+", z="+zBarrel);
+		    Hep3Vector p3 = new BasicHep3Vector(tr.getMomentum());
+		    double p = p3.magnitude();
+		    double pt = Math.sqrt(p3.x()*p3.x() + p3.y()*p3.y());
+		    System.out.println("   Track has p="+p+" and pt="+pt);
+		    validEndcap = validBarrel = false;
+		    m_intercept = null;
+		    m_swimmer = null;
+		    m_alphaIntercept = Double.NaN;
+		    return null;

 		} else {
 		    validEndcap = false;
 		}

diff -u -r1.4 -r1.5
--- TrackHelixPlusHitExtrapolator.java	9 Oct 2008 21:38:28 -0000	1.4
+++ TrackHelixPlusHitExtrapolator.java	27 Oct 2008 18:48:20 -0000	1.5
@@ -34,6 +34,13 @@

 
 	// Start by swimming as per parent:
 	super.performExtrapolation(tr);

+	if (m_swimmer == null) {
+	    // Failed to extrapolate completely -- didn't even fit a helix
+	    m_intercept = null;
+	    m_swimmer = null;
+	    m_alphaIntercept = Double.NaN;
+	    return null;
+	}

 	
 	// Now scan over tracker hits and find the outermost one.
 	// Note that the details here depend on what kind of hit