CALLBACK From the NASA Aviation Safety Reporting System
 Issue 455 December 2017 

Small Odds and Interesting Ends

NASA’s Aviation Safety Reporting System (ASRS) is a voluntary, confidential, and non-punitive reporting system for aviation safety that has served the aviation community since 1976. It is a successful and trusted program, forged from a cooperative effort between the FAA, NASA, and the aviation community. ASRS receives, processes, and analyzes voluntarily submitted reports from pilots, air traffic controllers, flight attendants, maintenance personnel, dispatchers, ground personnel, and others regarding actual or potential hazards to safe aviation operations. The program’s output currently includes aviation safety alert messages issued to appropriate agencies, research studies and special papers on various subjects, a searchable database with direct access to de-identified reports, and CALLBACK. The latter four are publicly available on the ASRS website.1

Value added to aviation safety stems from two important protections that the ASRS program offers to reporters. Confidentiality and limited immunity from FAA enforcement actions are afforded. Naturally, participation has consistently grown, and the result is the richness found in greater breadth and depth of reported incidents, lessons learned, and aviation wisdom. ASRS’s intake is robust, currently averaging 261 reports per calendar day and projected to exceed 95,000 in 2017.

With intake of that magnitude, ASRS receives reports on every conceivable topic related to aviation operations. This month we have reserved a few of the more unusual and light-hearted, but still important, incidents to share. Enjoy these “Odds and Ends” as we conclude another successful year.

Now You See it, Now You Don’t

A Bonanza Pilot became distracted and confused when he perceived the runway edge and centerline lights cycling on and off while ATC assured him that they were on steady.

I was transiting the final approach path of…Runway 16R and observed the runway edge and center line lights cycle on and off…at a rate of approximately 1 per second. It was very similar to the rate of a blinking traffic light at a 4-way vehicle stop. The [3-blade] propeller speed was 2,400 RPM. This was observed through the entire front windscreen and at least part of the pilot side window. I queried ATC about the reason for the runway lights blinking and was told that they were not blinking. It was not immediately obvious what was causing this, but I did later speculate that it may have been caused by looking through the propeller arc.

The next day [during] IFR training while on the VOR DME Rwy 16R approach, we observed the runway edge and center line lights cycle on and off…at a rate slightly faster than 1 per second. The propeller speed was 2,500 RPM. I then varied the propeller speed and found that at 2,700 RPM, the lights were observed strobing at a fairly high rate, and at 2,000 RPM the blinking rate slowed to less than once per second. This was observed through the entire approach that terminated at the Missed Approach Point (MAP). The flight instructor was also surprised and mentioned that he had not seen this before, but he also doesn’t spend much time behind a 3-blade propeller arc.

I would speculate that the Pulse Width Modulation (PWM) dimming system of the LED runway lights was phasing with my propeller, causing the observed effect. I would also speculate that the effect would…significantly differ at other LED dimming settings…and behind a 2-blade propeller.

I found the effect to be entirely confusing and distracting, and would not want to make a landing in such conditions.

Snakes on a Plane

A Large Transport Captain receiving a line check experienced a peculiar problem during the pre-departure phase of flight. He may have speculated whether the rest of the flight would be as “snake bitten” as the idiom implies.

Well within hearing distance of the passengers, the Gate Agent said, “Captain, I am required to inform you that while cleaning the cockpit, the cleaning crew saw a snake under the Captain’s pedals. The snake got away and they have not been able to find it. I am required to tell you this.”

At this time the [international pre-departure] inspection was complete, and I was allowed on the aircraft. I found two mechanics in the flight deck. I was informed that they had not been able to find the snake and they were not able to say with certainty what species of snake it was. The logbook had not been annotated with a write up, so I placed a write up in the logbook. I was also getting a line check on this flight. The Check Airman told me that his father was deathly afraid of snakes and suggested that some passengers on the flight may suffer with the same condition.

I contacted Dispatch and discussed with them that I was uncomfortable taking the aircraft with an unknown reptile condition.… The possibility [existed] that a snake could expose itself in flight, or worse on the approach, come out from under the rudder pedals. Dispatch agreed with my position. The Gate Agent then asked to board the aircraft. I said, “No,” as we might be changing aircraft. I then contacted the Chief Pilot. I explained the situation and told him I was uncomfortable flying the aircraft without determining what the condition of the snake was. I had specifically asked if the cleaning crew had really seen a snake. I was informed yes, that they had tried to vacuum it up, and it had slithered away. The Chief Pilot agreed with me and told me he would have a new aircraft for us in five minutes. We were assigned the aircraft at the gate next door.

…When I returned [to the airport], I asked a Gate Agent what had happened to the “snake airplane.” I was told that the aircraft was left in service, and the next Captain had been asked to sign some type of form stating he was informed that the snake had not been found.

Up, Close, and Personal

While attempting to mitigate a known, visible hazard, an Air Taxi Captain took special care to clear his wingtips while taxiing for takeoff. A surprise loomed ahead just as he thought that the threat had subsided.

Taxiing out for the first flight out of ZZZ, weed whacking was taking place on the south side of the taxiway. Watching to make sure my wing cleared two men mowing [around] a taxi light, I looked forward to continue the taxi. An instant later I heard a “thump.” I then pulled off the taxiway onto the inner ramp area and shut down, assuming I’d hit one of the dogs that run around the airport grounds on a regular basis. I was shocked to find a man, face down, on the side of the taxiway. His coworkers surrounded him and helped him to his feet. He was standing erect and steady. He knew his name and the date. Apparently [he was] not injured badly. I attended to my two revenue passengers and returned the aircraft to the main ramp. I secured the aircraft and called [the Operations Center]. An ambulance was summoned for the injured worker. Our ramp agent was a non-revenue passenger on the flight and took pictures of the scene. He stated that none of the workers was wearing a high visibility vest, which I also observed. They seldom have in the past.

This has been a recurring problem at ZZZ since I first came here. The operation is never [published in the] NOTAMs [for] an uncontrolled airfield. The pilots just have to see and avoid people and animals at all times. I don’t think the person that collided with my wingtip was one of the men I was watching. I think he must have been stooped down in the grass. The only option to [improve the] safety of the situation would be to stop completely until, hopefully, the workers moved well clear of the taxiway. This is one of…many operational deficiencies that we, the pilots, have to deal with at ZZZ on a daily basis.

Corrigan Conquers Again

An RV-7 Pilot was planning ahead for the weather he observed prior to departure. The weather, distractions, and personal stress influenced his situational awareness and decision-making during the takeoff.

I was cleared to depart on Runway 27L from [midfield at] intersection C. However, I lined up and departed from Runway 9R.… No traffic control conflict occurred. I turned on course and coordinated with ATC immediately while airborne.

I had delayed my departure due to weather [that was] 5 miles east…and just north of the airport on my route.… Information Juliet was: “340/04 10SM 9,500 OVC 23/22 29.99, Departing Runway 27L, Runways 9L/27R closed, Runways 5/23 closed.” My mind clued in on [Runway] 09 for departure. In fact I even set my heading bug to 090. Somehow while worried mostly about the weather, I mentally pictured departing Runway 9R at [taxiway] C. I am not sure how I made that mistake, as the only 9 listed was the closed runway.… My focus was not on the runway as it should have been, but mostly on the weather.

Contributing factors were:

1. Weather. 2. No other airport traffic before my departure. (I was looking as I arrived at the airport and completed my preflight and final weather checks). 3. Airport construction. For a Runway 27 departure, typical taxi routing would alleviate any confusion. 4. ATIS listing the closed runway with 9 listed first. 5. Quicker than expected takeoff clearance.
I do fly for a living.… I will be incorporating the runway verification procedure we use on the jet aircraft at my company into my GA flying from now on. Sadly, I didn’t make that procedural change in my GA flying.


ASRS Alerts Issued in October 2017
Subject of Alert No. of Alerts
Aircraft or Aircraft Equipment 4
Airport Facility or Procedure 4
ATC Equipment or Procedure 6
Other 1
October 2017 Report Intake
Air Carrier/Air Taxi Pilots 4,897
General Aviation Pilots 1,407
Controllers 544
Flight Attendants 411
Military/Other 320
Mechanics 233
Dispatchers 200
TOTAL 8,012
Indicates an ASRS report narrative
[  ]  Indicates clarification made by ASRS
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A Monthly Safety Newsletter from The Office of the NASA Aviation Safety Reporting System
P.O. Box 189  |  Moffett Field, CA  |  94035-0189
Issue 455