January 20, 2005 the FAA and NAV CANADA implemented Reduced
Vertical Separation Minimum (RVSM) from FL290 through FL410
inclusive. The vertical separation minimum is reduced from 2,000
feet to 1,000 feet and provides six additional flight levels.
RVSM is effective in the lower 48 states of the United States,
Alaska, Atlantic and Gulf of Mexico High Offshore Airspace,
and the San Juan FIR. Canada, Mexico, Caribbean, and South American
regions have also implemented RVSM in their airspace.
on documentation, certification, and operational policy and
procedures related to U.S. Domestic RVSM airspace are found
in FAA Notice GEN04009.
on incidents or concerns related to any aspect of Domestic RVSM
operations can be submitted to NASA ASRS on the appropriate
NASA ARC 277 General reporting form.
addition, the FAA is specifically requesting that pilots report
wake turbulence events that occur in RVSM airspace in the lower
48 states of the United States, Alaska, Offshore Airspace, and
the San Juan FIR.
DRVSM operational incidents and observations should be reported
on the appropriate NASA ASRS reporting form (available at: http://asrs.arc.nasa.gov/forms_nf.htm
Notice GEN04009 stipulates that pilots reporting on wake turbulence
incidents submit two forms:
NASA ASRS General reporting form for Pilots (NASA ARC 227B).
The "Type of Event/Situation" block on this form
should be annotated with the words, "Wake Turbulence."
FAA "Supplemental Wake Turbulence Information" form
reporting on wake turbulence incidents are encouraged to file
individual NASA ASRS reports even if a report has been filed
through the Aviation Safety Action Program (ASAP).
"Safety Reporting" section of the FAA's RVSM Documentation
Web Page provides links to the NASA ASRS General Report form
and the "Supplemental Wake Turbulence Information"
form. The links are found at the bottom of the page. (http://www.faa.gov/ats/ato/rvsm_documentation.htm
[Fig. 2] ).
reports to NASA/ASRS were received prior to the implementation
of DRVSM, however the "lessons learned" deal with
issues that are relevant to flight within all RVSM airspace.
this incident resulted from an encounter with "same altitude"
traffic, an increase in traffic-related maneuvering is possible
with the implementation of DRVSM. As this A320 crew suggests,
a simulator refresher on high altitude maneuvering might prevent
the need for adjusting passenger attitudes later.
gave us a 20-degree right turn for traffic and said, "Make
it a tight turn." I turned off the autopilot and immediately
commenced a turn. Simultaneously, we got a TCAS Traffic Alert.
The target was at the 11 o'clock position, amber, and closing
at our altitude. While [we were] still turning, the target
turned red and we got a TCAS II "Climb" Resolution
Alert. I advanced the power to TOGA and pulled up. In doing
so, I caused some G-loading and the airframe momentarily buffeted.
I rolled wings level, and decreased the climb rate. After
500-600 feet of climb, I leveled and we got a "Clear
of conflict" aural message. The flight attendants and
several passengers were standing at the time. Some passengers
were understandably concerned and upset. The Captain made
an explanatory PA. I have recommended simulator training in
high altitude RA maneuvers to my company. With Domestic RVSM,
this situation may well become more commonplace. Better training
is in order.
to coordinate with ATC, this B767 crew initiated lateral separation
to get out of a turbulent situation.
of the way across the North Atlantic, westbound, we began hearing
aircraft-to-aircraft reports of moderate to severe turbulence
at all altitudes approximately 200 miles ahead of our position.
These reports were coming from all the tracks. HF radio communication
was unavailable.... As we neared the North American coast, intermittent
VHF communication started, however the frequency was swamped
with position reports. No flights requesting altitude or flight
plan changes were being cleared. It became obvious that we could
not avoid the area of turbulence ahead vertically or laterally
and, of course, we had insufficient fuel to return anywhere
eastbound. We prepared the passengers, flight attendants, and
cabin for moderate or greater turbulence and slowed our speed.
An aircraft on our track, 2,000 feet above, slowed more than
us and we gradually flew beneath him. An aircraft on our track
1,000 feet below rapidly gained and flew beneath us.... Approximately
60 miles east of the area of reported moderate to severe turbulence,
we encountered severe turbulence at FL340. The nose pitched
up followed by a 30-degree left roll. Then the nose fell and
the stick- shaker was accompanied by buffeting. At this time
we received a TCAS Resolution Alert "Climb." Altitude
varied from 34,100 to 33,600 feet. The aircraft 2,000 feet above
us was approximately three-quarters of a mile ahead, however
the aircraft 1,000 feet below was directly beneath us on the
TCAS. Recovery to a climb to 34,000 feet and roll correction
right was made and we immediately broke out right of track to
exit this sandwich.
crew was conscientious about their altitude, but an error caused
by an altimeter malfunction still managed to creep up on them.
The reporter's remarks regarding DRVSM are worth noting.
through transition and resetting the altimeters to 29.92",
the First Officer and I cross-checked the altimeters to find
that they were within tolerance. We continued the climb to
FL330 using autopilot "A" which derives its information
from the Captain's equipment. Leveling at FL330, we again
cross-checked the altimeters. Mine read 33,000 and the First
Officer's read 33,160 feet. The standby altimeter read 33,140
feet. The First Officer's altimeter was reading slightly higher
than normal, but the standby altimeter reading was normal
(usually 150 feet high). The altimeters were within tolerance
and there was no cause for alarm. Since the Captain's altimeter
and the standby altimeters were reading their "normal"
split, we agreed that the Captain's was most likely the closest
to correct information and we kept autopilot "A"
15 minutes, I cross-checked the altimeters again. This time
the Captain's and the standby altimeters were unchanged, but
the First Officer's altimeter was now reading 33,200 feet....
An onboard mechanic...deduced the same as the First Officer
and I, that since the Captain's and the Standby altimeter
showed their normal split, that information was most likely
correct. We continued on autopilot "A" with the
Captain's altimeter continuing to read 33,000 feet.
Officer's altimeter continued to slowly creep to 33,240. We
were then advised by ATC that they were showing our aircraft
at 33,300 feet. We knew then that the Captain's altimeter
was the culprit and descended to FL330 using the First Officer's
altimeter. The altitude alert that warns pilots when they
have wandered 300 feet from their chosen altitude did not
activate. There were no traffic conflicts. We continued the
flight with the altitude based on the First Officer's altimeter
ground...the mechanic tested the air data computers and found
both to be operating normally. He then cleaned all the cannon
plugs in the altimeter system and the altimeters then agreed
identically. For [the next leg], the altimeters agreed with
less than 10 feet difference.
Captain's altimeter had been slowly descending and the autopilot,
in response, was ever so slowly climbing to maintain FL330.
We didn't catch it. Looking back, I should have immediately
queried the Center controller as to what he was showing on
his screen and now that DRVSM has begun, rest assured that
talking to the controller will be the first step should this
or a similar problem with altitude occur.
I should submit this report since it may help another crew
in the future, especially since altitude deviations are now
an even more critical event with DRVSM in effect. I know I
am doubling my attention to altitude now.
Recently Issued Alerts On...
engine flameout incidents
340B floor connector wiring fire
dual erroneous Primary Flight Displays
U.S. airport taxiway lighting deficiency
U.S. airport erratic localizer indications
December 2004 Report Intake
Carrier/Air Taxi Pilots