Calls for Wake Turbulence Reports
Since the inception of an FAA-funded
wake turbulence study in March 1995, the Aviation Safety Reporting System
(ASRS) has been collecting and analyzing wake turbulence reports submitted
by ASRS reporters. The study uses telephone interviews to obtain detailed
information about wake turbulence encounters. Its purpose is to gather
information which can be used to help reduce the frequency and danger
of wake turbulence events.
The collection of this data
is part of a larger ongoing FAA effort to track and monitor wake turbulence
incidents. As a result of the pilot response to previous announcements
in CALLBACK and other industry publications, the ASRS has been able to
conduct 131 telephone interviews with reporting pilots.
The FAA has asked ASRS to continue
the study; consequently, ASRS is again seeking pilot reports of recent
wake turbulence encounters--those that have occurred within the last
six months. Other details of the study's telephone interviews:
is entirely voluntary, and, as with all ASRS report information, all
personally identifying data (names, company affiliations, etc.) will
be deleted before the research results are given to the FAA. Only aircraft
make/model information will be retained in the ASRS data.
- Pilots who
submit recent wake turbulence reports to ASRS will be contacted
either by a telephone call to the phone number given on the reporting
ID strip, or by letter to the address listed on the ID strip (if no
phone number is given). Reports from both air carrier and general aviation
pilots are needed for the study.
- If the reporter
agrees to participate in the study, an ASRS analyst will make an appointment
for a forty-five-minute telephone interview to discuss the wake turbulence
incident and the factors that led up to it.
- As soon
as the interview is complete, the report ID strip will be returned,
with no record of the reporter's identity retained by ASRS.
ASRS reporting forms are available
at FAA Flight Standards District Offices and Flight Service Stations,
or they may be requested from ASRS by mail or phone. ASRS mailing address:
ASRS, P.O. Box 189, Moffett Field, CA, 94035-0189; ASRS phone: (415) 969-3969.
Forms may also be downloaded from the ASRS Internet "Home" Page
using the Adobe Acrobat Reader.
A frequent lament among reporters
who have participated in the ASRS wake turbulence study is that even when
they received wake turbulence warnings from ATC and followed appropriate
avoidance procedures, they still encountered another aircraft's wake.
An MD81 First Officer reports taking all the appropriate precautions when
trailing a B767, but environmental factors brought all the crew's efforts
- Wind was
reported 040 at 8 knots. ILS approach and landing to runway 4. We were
following a B767 by about 6 miles. I told the Captain that I would fly
one-half to one dot above glide slope for wake turbulence protection.
We were given all the proper wake turbulence and separation warnings
by both Approach and Tower controllers.
I was carrying much less power than usual, even staying one dot high.
At about 200 feet MSL, the airplane yawed and banked to the left. I
corrected with full right aileron and three-quarter right rudder, and
said, "I'm going around." I applied thrust...and as soon as
I pulled up, I regained complete control.
An Approach Controller...got word that the wind at the outer marker
for runway 4 was 210 at 40 knots. Then it made sense. The aloft tailwind...blew
the B767's wake forward into our glide path. I had never thought about
the effect of a tailwind on wakes. I do now.
Several reporters suggested
simulator and aerobatic training, or unusual attitude recovery training,
as valuable tools for surviving wake turbulence encounters.
Wake turbulence events on takeoff
are not as common as those encountered on arrival and landing, but can
be just as serious, as this B737 Captain reports:
- We were
cleared for takeoff right behind an MD80. As we rolled, he was just
lifting off. No clearance yet for visual separation. At about 800 feet
AGL, we rolled hard left, bank about 10-15º, with about 50-75%
aileron authority to counter the roll. The wake lasted about five seconds.
We hit it again at about 4,000 feet AGL, but only a momentary roll.
Separation was way too close for comfort!
Installation of a new or temporary
Tower may surprise some local pilots--like this general aviation reporter
who did not check NOTAMs before a routine flight:
- Local flight
of 15 miles on a CAVU day. Approaching my destination, I called for
traffic and runway advisory on CTAF, just like I had done for years.
No reply, but sometimes they are away from the radio, so no big deal.
I could see aircraft taking off and landing on runway 25, so I set up
for that, calling downwind and base. Then someone (unknown) called and
told me that there was now a Tower in operation on frequency 119.15.
Not wanting to make a bad situation worse, I made a go-around and switched
to the Tower. They cleared me for a normal landing.
This was NOTAMed, but really--who checks NOTAMs for a 15-mile flight
on a beautiful CAVU day? Me--next time.
Even when pilots check for
NOTAMs, they may still come up empty-handed, as did this ASRS reporter:
- I obtained
a computer briefing for VFR flight. I obtained flight following immediately
after leaving home airport, and continued flight following through two
states. About 15 miles north of XYZ, I tuned in XYZ ATIS to hear a message
that said the Tower was closed. There was nothing else besides this.
I overflew the Class D airspace at 4,000 feet, and landed [at the next
airport, 25 miles further south].
After refueling, I continued to [my destination], where I was asked
by ATC to contact an FAA person upon landing. I learned that a NOTAM
was in effect for the airspace above XYZ for an airshow.
Obviously, with enough diligence, I could have found this NOTAM and
avoided the airspace penetration. However, had the XYZ ATIS said more
than "The Tower is closed," I could have deviated in time
to avoid the area.
Included with the reporter's
mea culpa, a reasonable suggestion: The XYZ controllers might have included
specific information about the tower closure on the ATIS broadcast.
From Nose to Tail
A corporate pilot followed
standard company procedure for using a sport utility vehicle to tow an
aircraft out of the hangar. But the routine ferry flight to a maintenance
base turned out to be a little more exciting than planned.
the checklists, engine start, taxi, and runup, everything was normal.
As I rotated, right away I noticed that the airplane yawed some, and
it seemed to me that I had experienced a rudder boost failure. I retracted
the landing gear. The yaw ceased, the gear made a louder thump than
normal, but then everything seemed all right except the landing gear
handle light stayed on. Then it dawned on me--I hadn't removed the tow
bar. Was it still there?
I called Departure Control and advised them of the situation. They sent
a truck down the runway to see if the tow bar was anywhere to be found.
[It wasn't.] I decided to continue to our maintenance base, due to better
facilities and equipment to deal with who-knows-what on landing. The
Approach Controller set things in motion for my arrival. The Tower cleared
me for a low pass. The Controller could see the tow bar...it was being
held out forward at about a 60° angle by the nose tire itself. Amazingly
enough, I landed uneventfully, except that the initial touchdown sent
up quite a shower of sparks from the eye of the tow bar.
The only damage, besides that to my ego, was to the nose gear doors.
The reporter states that the
company's towing procedure has been changed to prevent this from happening
again. As if our reporter could ever forget!
now to the tail: a predawn departure set
the stage for this cargo carrier's First Officer to overlook an extra
- Upon landing,
we noticed the tailstand [tail support stand] had been left on the tail
during the flight. The tailstand was removed and the [subsequent] flights
resumed without incident. "Tailstand check" will be added
to my before-engine-start checklist. Pilot fatigue may have been a contributing
factor, coupled with the dark departure ramp not allowing you to see
the tail as you get in the plane.
One last look by a flight crew
member (with a flashlight, if needed) before boarding the aircraft, plus
adherence to "tailstand check" on the checklist, may keep other
crews from experiencing this potentially dangerous situation.
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1996 Report Intake