View Single Post
Old 11th March 2012, 05:51 PM   #190
Join Date: Aug 2006
Posts: 94 petition on inconsistant takeoff times.

Originally Posted by BCR View Post
I am not sure what the issue is here. I pulled the BTS records for both planes and indeed US 6805 has a Wheels-off Time of 8:28 and UAL 175 at 8:23, five minutes earlier. This tends to confirm the testimony of the US Air pilot. However, I also note there is only one UAL175 taking off, so beyond the time difference, where is the evidence that two 175's took off? I must be missing something.

If the evidence is that the 911 Commission time is earlier, that only means that the BTS time is different from the FAA time. There is a continuous radar track for the plane and we watched the impact live on television. This is not rocket science. All this means is there is a time difference between the two records, NOT that there were two UAL 175's.
The fact that the BTS time is different from the FAA time is the problem. The BTS tells us that UA175 took off at 8:23. The Commission using FAA time tells us that UA175 took off at 8:14.

UA93 has the same problem. It took off at 8:28 (BTS) or 8:42 (Commission).

The BTS wheels-off times are generated by ACARS when the wheels leave the runway.

The BTS actual departure times (also called push-back times) are generated by ACARS when the brakes are released and the aircraft moves. Here, the BTS times are the same (or one minute off) the times used by the Commission. That means the ACARS clocks were accurate.

The only attempted explanation for the inconsistency is the implausible idea that Air Traffic Control could have inaccurate clocks. Boston's ATC clock would be nine minutes behind, Newark's ATC clock 14 minutes ahead -- 23 minutes difference.

No official investigation has resolved the discrepancies. The BTS times seem totally ignored. I've started a petition at to officially investigate and reconcile the inconsistent times:

It need 150 signatures to even become visible on their petition site.
JohnM307 is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top