From: jcmorris@mwunix.mitre.org (Joe Morris)
Subject: ASRS CALLBACK # 163 (December, 1992)
Keywords: ASRS CALLBACK
Organization: The MITRE Corporation
Date: Wed, 30 Dec 1992 19:34:49 GMT


                     C   A   L   L   B   A   C   K

              From NASA's Aviation Safety Reporting System

     Number 163                                      December 1992

[This material is transcribed from the monthly safety bulletin _CALLBACK_
 as published by the ASRS office at Moffett Field.  It may include only
 a subset of the articles in the ASRS publication, and within a transcribed
 article I may exercise a mild editor's pencil for style or brevity.  Where
 appropriate I've marked edited material with /[ comments ]/; material in
 normal [brackets] was bracketed in the original text.]


READBACK/HEARBACK -- SOME FRESH IDEAS

The December 1989 issue of CALLBACK (Number 127) presented ASRS research
on *the readback/hearback problem*.  This is a pilot/controller communications
breakdown that results when pilots read back wrong instructions or numbers
(readback errors), and controllers fail to catch those errors (hearback
errors).  One of our research conclusions was that controllers may miss
pilots' readbacks during congested traffic conditions.

An Air Traffic Control Supervisor recently confirmed this conclusion in a
communication with ASRS.  He also offered some fresh ideas for improving
half of this problem -- controllers' *hearback* capabilities.  We'd like
to share some of his comments with you:

*** Readback/hearback...errors don't seem to be going away...What are we
    doing or not doing in our training programs to create this situation?

    The ATC controller training program is based on...increasing workload to
    reach a specific workload level while keeping errors below a specific
    number...Erroneous readbacks are not generally a part of the traffic
    scenario.  Consequently, remote [simulation] pilots read back clearances
    correctly unless they didn't really hear them correctly.  The student
    gets "trained" to get correct readbacks and soon learns that the time
    spent listening to readbacks can be used to plan and formulate clearances.
    When the student does not listen and the readback is correct, an
    undetected [listening] error has occurred.

    The student then carries this bad habit into the On-The-Job training
    experience. Once again the student must be efficient...so he or she uses
    the pilot's readback time to plan the next move.  If the readback was
    correct this will go as an undetected [listening] error.  By the time
    the student reaches Full Performance Level (FPL), this may have become
    ingrained in his or her mode of operation.  I believe it becomes so
    ingrained that the controller may even "turn off" the pilot during
    readbacks in moderate or lower traffic complexities...

    What can be done?  As with any problem, *Awareness* is the first key.
    Controllers, be aware of your propensity not to listen with full
    attention to readbacks.  Pilots, if you didn't hear that instruction,
    don't guess, ask for a repeat.  Next, include erroneous readbacks at
    every level of Air Traffic training so developmental controllers don't
    start down this road.

Some ATC facilities already use controller training scenarios that emphasize
detection of pilot readback errors.  An additional value of this training
is that it discourages controllers from anticipating pilots' responses --
another major source of controller hearback errors.


ORD PLEADS:  "DON'T CHANGE FREQUENCY UNTIL INSTRUCTED"

Changing frequencies without specific instructions from ATC is a hazardous
practice at any location, especially at one of the world's busiest airports.
A recent letter to ASRS from the Air Traffic Manager of Chicago-O'Hare
(ORD) Control Tower described two operational errors that resulted from
unauthorized frequency changes by pilots.  Some excerpts from this letter:

*** An arriving aircraft for Runway 14R landed and was instructed to
    exit the runway and report clear.  However, the aircraft exited the
    runway and the pilot changed frequencies without reporting clear.
    The subsequent [following] aircraft was issued a missed approach and
    a controller error occurred with another aircraft departing Runway 22L.

    A second error occurred when three aircraft of the same company and
    type, landed on Runway 4R and exited at the highspeed taxiway just
    south of Runway 9R.  /[The departure ends of 4R and 9R form the vertex
    of a "V".  The taxiway for 4R is to the north of the runway, and
    eventually crosses 9R.  The terminal is to the north of 9R.  jcm ]/
    As the third aircraft was rolling out, the first two aircraft were
    instructed (by Local Control) to cross Runway 9R and contact Ground
    Control on the north side of the runway.  The third aircraft exited
    Runway 4R at the highspeed and changed to Ground Control frequency.
    Aircraft #3 now became the first aircraft to make contact with
    Ground Control and was issued taxi instructions to the gate.  The
    aircraft crossed an active runway without Local Control clearance.
    Fortunately, there were no arrivals at the time.

ASRS encourages flight crews to follow ATC frequency instructions at all
times, especially during taxi operations that follow landings.  In
situations where it is critical that aircraft not change frequency
prematurely, a controller reminder (workload permitting) to "Remain on
this frequency" may help prevent runway incursions and other conflict
situations.

/[ See also AIM paragraph 235(b)  jcm]/


GENERAL AVIATION WEATHER INCIDENTS

        by Betty Hicks

---------
Editor's note: Betty Hicks is an ASRS Research Consultant.  Part 1 of her
article, published in the November 1992 CALLBACK, focused on the types of
weather encountered by general aviation pilots who reported weather
incidents to ASRS.  In this Part 2 conclusion, Ms. Hicks identifies
the judgement and training factors that contributed to these weather
incidents.
---------

*** I leveled at 11,000 feet and asked to deviate to avoid the buildup.
    An exasperated sounding controller told me I could not deviate west.
    A few minutes later the controller told me if I could not fly in
    IMC he would have to reroute me.

*** My experience with FAA weather briefers is that the conditions are
    usually grossly overstated.  They cannot be believed most of the time.


To learn more about the types and causes of general aviation weather
incidents, we analyzed 146 weather-related incident reports from the
ASRS database for the period 1986 to 1991.  Approximately half of these
reports involved IFR flight plans, and half involved VFR flight plans
or no flight plan.  We learned that the majority of pilots on IFR flight
plans had encountered *icing*, *thunderstorms*, and *turbulence*, while
a majority of those on VFR/Non flight plans had encountered *low ceilings
and/or visibilities*, and *lowering ceilings and merging layers*.

What were the factors that contributed to these reporters' unfortunate
adventures?

IFR FLIGHT PLAN WEATHER INCIDENTS.  Within the IFR flight plan group of
incidents (76 reports), pilots' *inadequate knowledge of ATC procedures
and regulations* contributed to more than one third of the incidents.
Many reporters faulted ATC for lack of cooperation in an emergency or
near emergency situation.  They failed to realize that their demands of
ATC were not in the controllers' jurisdiction, were beyond the capabilities
of ATC radar (as opposed to cockpit weather radar), or could not be met
due to ATC regulations or procedural dictates.

"If the controller had allowed us to descend earlier, we would not have
been in danger," was a typical conclusion from a pilot unaware that
Minimum Enroute Altitudes (MEAs) are sacrosanct.  The controller could
not legally approve flight below the MEA.

The pilot who, with 1 mile visibility, requested a *visual* approach as
the ice built up on the airfoils, missed some important distinctions in
ground school.  The pilot request should have been for a *contact*
approach, which ATC might have approved.  The request for a visual
approach was denied.

Other significant contributing factors in this group of reports were
*"if-it's-legal-it-must-be-safe" mindset*, and *failure to declare an
emergency*.  Twenty-two reporters appeared to regard the instrument
rating as carte blanche.  Some launched their IFR flights in the face
of forecasts predicting icing conditions, thunderstorms, and mountain
wave activity, but failed to explain why they did not consider a No-Go
decision.  Others continued IFR flight despite equipment malfunctions
and weather in which their aircraft were not equipped to fly.  Six
reporters in this group failed to declare an emergency, when this
declaration would not have overstated their plight.

VFR/NON FLIGHT PLAN ENCOUNTERS.  Within the group of incidents that occurred
on VFR flight plans or no flight plan (70 incidents), limitations of the
weather delivery system -- especially incomplete or inaccurate weather
forecasts -- were cited by more than one third of the reporters.  A major
cause of one pilot's TCA incursion was "a sketchy weather briefing.  I
don't recall if I told the briefer that I was a student pilot or not, but
when I departed I did not have a good picture of the weather ahead."

Another reporter gave voice to a persistent myth -- that FAA weather
briefers are "not to be believed most of the time."  His reward for
spiraling through BINOVC (breaks in the overcast) was a "Gotcha!"
from the 800-foot ceiling at the base of the overcast.

Sifting through these complaints, we discovered that many of these pilots
apparently had been content at briefing time to be *inert recipients of
whatever the system delivered*, rather than becoming active participants
in the weather briefing process -- questioning, comparing, analyzing.
Not one reporter indicated that he or she had obtained temperature-dewpoint
data, an important indicator of the condition of the atmosphere.  Only
one pilot mentioned an attempt to contact Enroute Flight Advisory Service
(EFAS), a mother lode of real-time weather information, and particularly
of PIREPs.  A lone reporter mentioned submitting a PIREP on encountered
weather.  Six reporters failed to distinguish between weather *reports* and
weather *forecasts*.

Another significant contributing factor to this group of incidents was
*failure to make a timely 180-degree turn*.  Our analysis counted eight
situations in which pilots did not look behind them often enough,
allowing their 180 degree options to self-destruct.  The plots -- and
the clouds -- thickened.  Ten reporters *exceeded their limitations*;
eight of these pilots became dangerously unsure of aircraft positions
on VFR flights into and out of IMC conditions.  None of the eight reported
attempting VOR position fixes, a rudimentary private pilot procedure.

    LESSONS LEARNED.  This study identified several overall causes of
    weather-related incidents in both IFR and VFR general aviation
    operations:

 >> INADEQUATE KNOWLEDGE OF HOW TO USE THE SYSTEM EFFECTIVELY.  A
    number of IFR pilots demonstrated deficient knowledge of ATC
    procedural and radar limitations.  VFR pilots often failed to
    become active participants in the weather briefing and data
    delivery process.

 >> AN "IF-IT'S-LEGAL-IT-MUST-BE-SAFE" MINDSET.  Instrument-rated
    pilots could legally take off (and some did) in zero-zero
    conditions into known icing under FAR Part 91.  Similarly,
    many VFR pilots legally launched into low ceilings and visibility
    conditions, exceeding their own limitations and those of their
    aircraft.

There were doubtless many other pilots between 1986 and 1991 asking
intelligent questions of their briefers, analyzing potential icing
conditions, and fighting the urge to fly in 1000-3 conditions.  But
until 146 weather incidents are reduced to zero, the reality is apparent:
Someone in the system is not getting the job done.



--------

October 1992 report intake:

  Air carrier pilots . . . . . . . . .  1689
  General Aviation pilots  . . . . . .   755
  Controllers  . . . . . . . . . . . .    89
  Cabin/Mechanics/Military/Other . . .     1
Xref: sparky rec.aviation.misc:1129 rec.aviation.ifr:537