PILOTS: Here is the approach plate for LOC 18 in Birmingham. The overriding question in the crash of UPS 1354 is, with the airport PAPI operating properly and the A300’s autopilot engaged, how did the pilots descend below the 556 AGL minimum prior to reaching the IMTOY fix? Why were they that low that soon? — Terry Meiners
Here are three columns from industry publications:
FLIGHT SAFETY INFORMATION
ISSUE NO. 172
AUGUST 21, 2013
UPS 1354 data suggest approach or equipment anomalies
Cockpit voice recorder data from the UPS A300-600F freighter that
crashed on approach to Birmingham, Alabama, before sunrise on August 14
reveal an impact with either trees or terrain 4 seconds after one of the
two pilots called out, “runway in sight”.
The short time span between runway sighting and ground or tree
collision likely indicates that the pilots were either using a modified
instrument approach procedure for Runway 18, or that there was an error
or confusion leading them to believe the aircraft was at a higher
According to instrument approach charts for the localizer
approach to Runway 18, the non-precision approach which UPS Flight 1354
was using to land that morning, the aircraft is not to descend below 556
ft. above the ground (1,200 ft mean sea level) until the pilots visually
spot the runway “environment” through the windscreen.
U.S. National Transportation Safety Board member Robert Sumwalt,
during a press briefing on August 16, said there were sounds “consistent
with an impact” at 9 seconds before the cockpit voice recorder (CVR)
stopped working, though he did not specify if those sounds were the
aircraft striking tree tops in a neighborhood along the final approach,
or the impact of the A300 on a hillside approximately 0.5 mi. before the
runway end. He did say investigators looking at the A300’s Pratt &
Whitney PW4158 engines determined that it had ingested “trees and dirt”.
Either way, the A300 was much lower than it should have been on
the localizer 18 approach if pilots sighting the runway only 4 seconds
before the sounds of an impact with an object at or near ground level.
Typically, pilots begin descending from the minimum descent altitude
(556 ft. AGL in this case) upon sighting the runway, which means that 4
seconds after sighting the runway, the aircraft should have been
hundreds of feet above terrain.
For a localizer approach, pilots use the ground-based localizer
for left-right guidance and the aircraft’s barometric altimeter for
altitude information. Without vertical guidance, the approach is
considered “non-precision” and has higher minimums (the lowest altitude
to which the aircraft can descend without pilots having the runway in
sight) compared to a precision approach. Birmingham’s other runway has
an instrument landing system (ILS) precision approach with vertical and
horizontal guidance, but the runway was not usable that morning due to
work in progress on its centerline lighting system, said Sumwalt.
When completing the approach visually, pilots generally use the
precision approach path indicator (PAPI) system located near the runway,
a row of four white or red lights that show the aircraft’s vertical
position with respect to the ideal glideslope. Sumwalt says the FAA
tested the PAPI after the accident and found it to be accurate.
Aircraft performance and energy appeared normal based on initial
indications from the flight data recorder (FDR). Sumwalt said control
inputs and aircraft flight control surfaces appear to correlate properly
and engines indicated normal operations.
The aircraft’s autopilot was engaged until the last second of FDR
data and the autothrottle system was engaged through the end of the
data, said Sumwalt, with the recorded airspeed tracking the autoflight
selected airspeed of about 140 kt., which is consistent with the
expected approach speed for A300. Sumwalt noted that the CVR operated
for a few seconds after the FDR stopped.
Sumwalt also reported that 3 seconds before a pilot called
“runway in sight”, there were two audible “sink rate” alerts issued by
the enhanced ground proximity warning system, indicating a descent rate
that was outside the bounds of the expected descent rate for the speed,
altitude and aircraft configuration at the time.
The NTSB plans to fly another UPS A300 on the approach to
Birmingham in the next few weeks to observe the company’s procedures for
using the Runway 18 localizer approach, says Sumwalt.
Autopilot, Autothrottles Engaged in UPS Crash
Raising questions about what role automation may have played in
the August 14 UPS crash at Birmingham Shuttlesworth International
Airport, the NTSB revealed that the Airbus A300’s autopilot and
autothrottles were engaged all the way to the point of impact about
three quarters of a mile short of the runway.
According to the NTSB, the crew briefed the localizer approach to
Runway 18 as they descended toward the airport on the 45-minute flight
from Louisville, Kentucky. The captain of the Airbus A300-600 was flying
with a selected approach speed of 140 knots, said NTSB board member
Robert Sumwalt. That speed would have been consistent with the A300 at
its landing weight.
Two minutes before the end of the cockpit voice recording the
A300 was cleared to land on Runway 18. As the A300 approached the
airport from the north, 7 seconds prior to impact, an audible “sink
rate, sink rate” warning was heard from the ground proximity warning
system in the cockpit. Four seconds before impact one of the pilots
announced that the runway was in sight.
The A300 struck trees short of the runway before impacting a
grassy rise and bursting into flames, killing both crew members. The FAA
over the weekend flight checked the PAPI system for Runway 18 and found
that it was properly aligned with the approach path. Next investigators
plan to fly the Runway 18 localizer approach in a UPS A300 with a
qualified UPS crew to observe the company’s operating procedures.
All aircraft systems appear to have been functioning normally at
the time of the crash, according to a preliminary readout of the flight
data recorder. Sumwalt said controllers did not receive a minimum safe
altitude warning at any point during the A300’s approach.
WHY THE UPS CRASH IS SUCH A SHOCK
For a widebody twinjet operated by a US carrier into a US airport to
crash on final approach in good weather is a statistical shock. It
wouldn’t have been such a surprise ten or 20 years ago, but these things
‘just don’t happen now’, so they are disproportionately shocking when
Let’s look at why it’s such a surprise.
* North America’s commercial air transport is consistently at the top of
the world’s safety league;
* UPS has high safety standards, runs a disciplined safety management
system, and involves its crews in the SMS;
* The aircraft, an Airbus A300-600F, was only ten years old – youthful
for an aeroplane – with relatively low flight hours and cycles for its age;
* The visibility was good and the cloudbase high.
* There was no emergency call.
* It was a routine scheduled flight for UPS.
On the other hand, did the crew face any disadvantages?
* It was just after 05:00 local time when the accident happened, which
is a natural human circadian low point affecting performance (but on the
other hand night flying is mostly what UPS pilots do);
* Runway 18 is not the main runway at Birmingham, it has no glideslope
guidance on approach apart from the precision approach path indicators,
and the runway has simple edge lighting.
That’s about it.
If the crew had a problem they didn’t tell anyone about it. Of course
that could be because they were too busy dealing with it to make a call.
Then the aeroplane got so low on the approach it hit the ground well
before the runway threshold.
A few parts of the world, including the USA, are within reach of the
holy grail of zero fatal accidents in commercial aviation. But what does
it take to get there?
When so few accidents happen, lessons from them are important. Although
the aviation world is gradually getting better at gathering and
assembling data pointing to where operational and technical risks lie,
the difference between an incident and an accident is what tipped it
over the edge. We want to know what that was at Birmingham, Alabama.