Unaware and Unafraid, in the Undercast


Staff member
Regardless of who is at fault, everyone loses in a midair…..

13 March 1982
5 miles south of Luke AFB (KLUF), Glendale, Arizona
Midair Collision:
American AA-1A Yankee, N6160L / Boeing KC-135A Stratotanker, 57-1489 “Copper 5“; 161st Air Refueling Group (AFREG)/ 197th Air Refueling Squadron (AREFS), Arizona ANG

6 Fatal

In this 17th installment of MikeDs Accident Synopsis series, and the 4th installment detailing a midair collision, I again attempt to cover a different facet of midair collisions and their causal factors. Where many midair collisions often come across as random events of two unrelated aircraft coming together, or of a planned event gone wrong such as briefed or unbriefed formation flight; it’s somewhat rare to find the midair collision that’s the direct result of a regulation being broken or ignored by one of the involved aircraft. Most of the time, any midair collision that occurs in Visual Meterological Conditions (VMC) is the result of some kind of failure to see and avoid, oftentimes by both aircraft involved. In today’s accident, I discuss how and why certain Federal Air Regulations (FARs) exist, and what kind of accident scenarios they are directly designed to prevent or at least severely mitigate.

The morning of Saturday, 13 March 1982 was cool with light breezes following the passage of a cold front overnight. Lingering early morning clouds reported around 3,000 Scattered to 4,000 broken persisted, but were anticipated to burn off as the day progressed. The pilot of American AA-1A Yankee N6160L received this information in person at the Phoenix Flight Service Station (FSS) [no longer in existence, it used to be next to the Phoenix TRACON building back at Phoenix Sky Harbor Airport then - MikeD], along with other weather information he needed for his return trip with his one passenger to Livermore, California airport (ICAO: KLVK), from where he had arrived to Phoenix-Sky Harbor Airport (ICAO: KPHX) on a cross-country flight the day prior. While receiving the weather information from the FSS briefer, the pilot of 6160L encountered a pilot of a Cessna 177 Cardinal who, by coincidence, was also proceeding to KLVK that morning, and wanted to listen in on the weather brief being given. As both pilots shot the breeze in the FSS lobby, and discovering that they had similar planned takeoff times, both pilots agreed to remain in visual and radio contact with one another for the planned VFR flight westbound to California and the same destination of Livermore airport. Both pilots filed their VFR flight plans with the FSS briefer, and at around 1030L, both 6160L and the Cessna Cardinal, each with two persons onboard, departed KPHX, with the Cardinal approximately 2 miles behind 6160L. The Phoenix tower local controller gave each aircraft a 30 degree check turn from runway heading, then handed each aircraft off in-turn to the Phoenix Terminal Radar Approach Control (TRACON). In 1982, Phoenix, airspace-wise, was a Terminal Radar Service Area (TRSA), which did not require mandatory participation from VFR aircraft. It wasn’t until around 1985 that Phoenix became an Airport Radar Service Area (ARSA, now known as Class C airspace), and in 1991 became a Terminal Control Area (TCA, now known as Class B airspace). The TRACON controller received the check-in of both 6160L and the Cessna Cardinal, and cleared both on-course and to maintain VFR, 2,600 [msl] while in the TRSA. Both 6160L and the Cessna Cardinal complied, turning westbound on about a 290 heading, to join Interstate 10 in west Glendale (in 1982, I-10 didn’t come all the way into the valley to “the stack” interchange downtown, as it didn’t exist then. I-10 began/ended at Litchfield Road) and continue westbound to Blythe. Radar service was terminated by the TRACON at 1040L about 8 miles west of KPHX, and both planes were cleared to squawk VFR and change frequencies. Both 6160L and the Cessna Cardinal pilot met up on 122.9, and established radio contact. Clouds were noticed to be heavier broken-overcast in this area of the west Phoenix valley due to the Estrella mountains starting to the south. These lower than forecast ceilings existed at about 2500’ broken-overcast, vice the 4000’ broken reported. The pilot of 6160L stated on the radio that he was “following the freeway to Buckeye VOR” and remained at 2500‘-2600’ MSL, while the Cardinal pilot deviated a mile south and descended to 2000’ MSL to avoid the clouds. Looking to his 2 o’clock, the Cardinal pilot could see 6160L skimming the bottom of the overcast layer, in and amongst the clouds, as the two aircraft proceeded along Victor 16, approximately 6 miles southwest of Luke AFB (KLUF) at about 1049L time.

Approximately 3 hours prior to this time, three Boeing KC-135A Stratotanker aerial refueling jets of the USAF Arizona Air National Guard 161st AREFG/197th AREFS departed their home base of KPHX, just on the other side of the field south of the Phoenix FSS, on a formation navigation training mission. Their briefed route of flight for the roughly 3.5 hour mission was Prescott via the DRAKE Standard Instrument Departure (SID), direct Winslow VORTAC for celestial navigation practice east of Air Refueling (AR) track 658, then pick up the Winslow transition to the EAGUL Standard Terminal Arrival (STAR) to the Phoenix area, with a formation breakup prior to entering the Phoenix airspace. Each KC-135A carried a crew of 4: Aircraft Commander, Co-Pilot, Navigator, and Boom Operator. The bulk of the mission was uneventful and executed as-briefed through the celestial navigation training and the EAGUL arrival. At 1018L and 30 miles north of the Phoenix area, the formation executed their break-up into three single-ship elements. One of these three aircraft was 57-1489, callsign Copper 5. As with the other two KC-135As in the formation, Copper 5 remained with Albuquerque Center (ZAB) during the formation break-up, taking a heading for spacing and gaining altitude separation as well as a squawk code. Copper 5 was then handed off by Center to Phoenix TRACON. Checking in with TRACON, the crew of Copper 5 requested, and was granted, a full procedure practice HI-TACAN 3L instrument approach, with a touch and go and back to the radar pattern. As Luke AFB Radar Approach Control (RAPCON) was closed on the weekends and their Airport Surveillance Radar (ASR) shutdown during the same time, Phoenix TRACON maintained positive radar control of Copper 5 as it was cleared to descend to 12,000’ MSL and radar vectored to the LENNI initial approach fix, to commence the HI-TACAN 3L approach procedure, still under IFR. Proceeding as published via the 16 DME arc, Phoenix TRACON handed off Copper 5 to Luke Tower, and this first instrument approach was completed to a touch and go on RWY 3L, with Copper 5 executing a climb out and re-contacting TRACON, with a request for another practice TACAN 3L approach. Luke AFB advised that they could not take another practice approach, due to recovering F-104G Starfighter traffic. Weather at the time at Luke was reported on the 1055L Surface Aviation weather report (hourly) as 3000’ scattered, ceiling 3500’ broken, visibility 20, wind 120/5, temp/dew point 58/48, altimeter 29.94. However as stated earlier, ceilings further south outside the Luke Airport Traffic Area (ATA, now Class D airspace), were significantly lower in the 2300’-2500’ MSL range. Copper 5 had been in and out of this cloud deck and one layered higher, during the intermediate segment of the TACAN approach and approaching the Final Approach Fix (FAF).

Due to the traffic load at Luke and inability to accept further practice approaches, Phoenix TRACON offered instead an ILS 8R approach to KPHX for Copper 5, which they accepted. Moments later however, Luke Tower called TRACON on the landline and advised that could indeed accept another practice approach for Copper 5. Copper 5 was again vectored to LENNI for the HI-TACAN 3L, and was cleared for the approach. Copper 5 crossed LENNI inbound and turned to intercept the 16 DME arc, arcing southwest and crossing the mandatory altitudes of 7000’ and 5000’ on the DME arc, prior to turning inbound on the 030 degree final approach course (now 032 on current plates). Crossing 12.5 DME inbound at 1047L, Copper 5 was handed off by TRACON to Luke Tower. Configuring with landing gear and flaps, and running their final landing checklists, Copper 5 began entering the tops of the cloud overcast as the KC-135A descended to the FAF altitude of 2700’ MSL at 6 DME from the field. Copper 5 contacted Luke tower and was advised to report FAF inbound with [landing] gear. At 1049L, Luke tower controllers saw a target on their BRITE scope and issued a traffic advisory “…Copper 5, traffic 5 miles south of the field, light civil maneuvering, altitude unknown.” This traffic seen on the BRITE scope, which didn’t show altitude, was the Cessna Cardinal, located about 7 DME from the field and at 2000’ MSL, westbound. Copper 5 advised “…final approach fix inbound, we’re popeye [in the clouds]”. In the middle of this transmission, Luke tower personnel visually spotted another light civil aircraft skirting the bottom of the cloud deck, also westbound. At that exact same moment, Copper 5 began emerging from the bottom of the undercast at 2700’ MSL and descending. The second light aircraft spotted by Luke tower, N6160L, began what was described as a steep evasive turn to the left (south), while still at the bottom of the undercast. From Copper 5’s roughly 3 o’clock position, 6160L struck the KC-135 just aft of the R2 door on the right rear fuselage center, while in a steep left bank. 6160L was immediately destroyed in the resulting explosion of the Yankee’s main fuel tank against the KC-135, and it’s remains spun down to earth. The KC-135A, having not seen 6160L, had not taken any evasive action. During the impact, the KC-135A suffered damage to the right fuselage and upper fuselage, associated flight control cabling, as well as the right horizontal and vertical stabilizers, with the empennage eventually separating from the fuselage. The KC-135A was seen by ground witnesses to pitch up slightly, then pitch down to nearly 80-90 degrees nose down in an uncontrolled descent, crashing into the grounds of the Perryville State Prison and exploding in a post-crash fire. Both the pilot and passenger on 6160L, as well as the 4 crew of Copper 5, including the commander of the 197th AREFS who was the aircraft commander, were killed. The Cessna Cardinal, uninvolved in the accident itself, reported the accident to Phoenix-Litchfield (Goodyear- KGYR) tower, and landed at that field approximately 8 miles southwest of Luke AFB.

Probable Cause

*VFR Procedures- Improper- Pilot In Command, N6160L
*Visual Lookout- Inadequate- Pilot In Command, N6160L

Secondary Factors

*Improper Use of Procedure, Lack of Familiarity With Geographic Area- Pilot In Command, N6160L

Tertiary Factors

*Enroute Charts- Sectional Aeronautical Chart- Inadequate- Federal Aviation Administration

MikeD says:

This accident emphasizes the importance of complying with rules and regulations, in this case as they have to do with the General Flight Regulations of 14 CFR 91. As with any accident, some interesting items come to light during the investigation, both related to the accident, as well as potentially related. Once the onion is peeled back on the causal factors, some revealing items show up surrounding the pilot of 6160L, as well as what was discovered in the tertiary factor that may not have come to light had it not been for this accident happening in the very geographical place that it did. I will therefore focus on the following two items:

1. 14 CFR 91 and the pilot of N6160L,
2. Charting issues discovered with the Phoenix Sectional Aeronautical chart.

14 CFR 91 and the pilot of N6160L:

As I’ve stated many times before, a pilot's actions and inactions often set the stage for an accident. The case is no different in the case of this accident. The first issue is glaringly obvious: VFR cloud clearances. 14 CFR 91.155(a) discusses VFR cloud clearance requirements in various airspace types. In basic controlled airspace (known now as Class E airspace), the requirement is 500’ below, 1000’ above, 2000’ horizontal, and 3 miles visibility. The pilot of 6160L maintained essentially the last altitude clearance given to him by Phoenix TRACON, the 2,600’ VFR, even after being released from ATC control. The pilot of 6160L did not contact Luke AFB tower, since where he was located, while technically inside the Luke AFB Control Zone (keyhole slot), he was outside the Luke Airport Traffic Area (Class D) and the field was VFR, hence he had no requirement to contact Luke for an airspace transition. What would make the pilot of 6160L remain so close to clouds, even while his friend in the Cessna Cardinal deviated south and descended in order to avoid the clouds? The Cessna Cardinal pilot, for his part and asked if he thought it odd for 6160L to be flying so close to the clouds, agreed with that assessment, but didn’t say anything to the pilot of 6160L over 122.9. Interestingly enough, the pilot’s logbook was acquired during the course of the investigation.

In his logbook, the pilot of 6160L had many entries in the remarks section regarding his individual flights, nearly filling up the remarks section of each flight entry. Much of the pilot’s 598 hours TT, with 110 in type, on his Private Pilot license, had all been in and around the southern California area, with only two cross-country flights outside the state: one to Nevada, and this particular flight to Phoenix. This particular pilot’s logbook was far more than simply an official record of flight times and currencies, it was almost a flight diary. What was contained in the remarks section of many flights was revealing: comments such as “flight in the clouds”, and the like were in many logbook entry remarks. Now in and of itself, this isn’t specifically incriminating, as there isn’t enough information to determine if these entries mean busting into IMC, or simply flying “amongst and around” clouds, or cloud chasing. Still, the comments tend to show a trend of cloud chasing at best, cloud penetration with no instrument rating or clearance, at worst. This could explain why the pilot of 6160L seemed comfortable being where he was at the bottom of the undercast, and seemingly unaware of the potential danger for why those cloud clearance regulations exist when VFR. In order for concepts like “see and avoid” to be even remotely effective, there needs to be the opportunity TO see and avoid, something that doesn’t exist when one is flying right next to, or even slightly into, clouds. Certainly when flying in the middle of nowhere, the chances of an aircraft descending through an undercast on top of you are nil to none; however in a fairly dense air traffic environment, where a Victor Airway crosses a Final Approach Fix for an instrument approach to an air base, the chances become a lot higher. Granted, the pilot may not have been aware of this or even its possibility, due to his lack of an instrument rating; but there were warning signs on VFR charts too, even though they were later found during the course of the investigation to be somewhat vague in nature.

Charting issues discovered with the Phoenix Sectional Aeronautical Chart:

During the course of the investigation, some revealing items not previously noticed or paid attention to came to light regarding the charting of the Phoenix Sectional Aeronautical Chart, and changes to the chart resulted from the recommendations of the investigators. As stated previously, there was a vague and poorly written warning depicted on the sectional chart regarding Victor Airway 16 and jet traffic from Luke AFB. That Warning stated:

“WARNING: Heavy jet traffic crossing V16. Aircraft must transit this area of V16 at 2000’ MSL or lower, or at 5500’ MSL or higher from 0600 to 0100 the following day local time Monday through Saturday”

Not only was this warning vague and poorly written, it was located some distance away on the sectional chart itself from the affected area it was supposed to cover. The actual warning was located nearly 12 chart-miles west of the position of V16 where the accident occurred, on the west side of the Alert Area A-231 airspace box, and not obvious that it covers the area in question or would even be noticed by someone navigating with the chart westbound and in the area of the collision, as that person would have to look 12 chart-miles further west than where he is, to even notice the warning box. Further, the times are depicted in Local instead of Zulu, and “…to 0100.…through Saturday” one would construe to mean ending on 0100L Saturday early morning, when the warning actually refers to “…the following day…” of 0100L Sunday morning.

Oddly enough, when investigators referenced the Low Altitude Enroute IFR chart for this exact same area as a comparison measure, they noticed that there was also a warning depicted, however this warning was both more clearly worded, the times were in Zulu, and the warning itself was depicted much closer to the actual affected airspace area that it’s referring to. That warning reads:

“WARNING: Special Air Traffic Rule FAR 93.75 (Aircraft operated under VFR). Heavy jet traffic crossing V16. Aircraft (other than jet aircraft assigned to Luke AFB) must transit this area of V16 at 2000’ MSL or lower or at 5500’ MSL or higher from 1300z to 0800z Mon-Sat.”

What the reason was for the two differently-worded warnings regarding VFR flight in this area on two different charts covering the area, was never explained. Today, that airspace in the Phoenix west valley surrounding Luke AFB has been turned into a Special Air Traffic Area that sits just outside the western edge of the Phoenix Class B airspace. The new warning for that airspace reads as-follows:

“SPECIAL AIR TRAFFIC RULE FAR PART 93 SOUTH OF LUKE AFB CTC LUKE APP ON 125.45. Pilots are required to establish two-way communication with Luke App prior to entering the Special Air Traffic Rule (SATR) Area and maintain communication while operating in the area (See Phoenix Terminal Area Chart)”

Lastly, one other glaring standout regarding the Phoenix Sectional Aeronautical Chart stood out directly with regards to the geographic location of this accident. In 1982 and prior, the metropolitan Phoenix area was split in half on the actual Sectional Chart sides: the northern half of Phoenix charted on the bottom of the “north” side of the chart, and the south half of Phoenix charted on the top of the “south” side of the chart. Split evenly at this exact half-way point, was Victor 16 going westbound out of Phoenix to Buckeye VORTAC (BXK). If a pilot happened to be navigating using the south half of the chart, he would never see the Warning regarding V16 and the jet traffic, as it was depicted on the north half of the chart, north and west of Luke AFB. Even if navigating using the north side of the Sectional chart, the Warning still would not stand out, for the previous reasons regarding its location on the chart itself. This anomaly had not been previously noted as a potential hazard, until this accident came about, even though this factor is only a tertiary factor discovered during the course of the investigation. In future editions of the Phoenix Sectional, and to this day, 90% of the Phoenix Metro area and Class B airspace is depicted on the south side of the chart, while about 30% of the Phoenix area and Class B is depicted overlapping on the north side of the chart. Additionally, the entire Phoenix metro area and Class B airspace is depicted on one page of the new Terminal Area Chart, something that obviously didn’t exist back in 1982.

MikeDs Final Thoughts:

There is a reason the old adage talks about regulations being “written in blood“, or even potentially being written to avoid that, because many regulations serve to protect pilots from mishaps, and often are the result of an accident having occurred with regards to what they cover. Failure to follow regulations, or even a lackadaisical attitude towards them is often the first layer in the series of cheese slices in James Reason’s “Swiss Cheese Model” that allow a potential accident to begin on its path of occurring. As discussed in the opening to this Accident Synopsis, this particular midair collision wasn’t one of those random events, or even a planned event between two related aircraft gone wrong. This accident was purely due to failure to follow a cloud clearance regulation. And although both involved aircraft were perfectly legal to be where they were geographically, the pilot of 6160L was not legal to be where he was vertically, as the pilot of the Cessna Cardinal recognized and mitigated. Whether this was an error or omission (lack of situational awareness to risk or safety) or whether it was one of commission (deliberate and/or pre-meditated breaking of regulations), the probability remains very high that this accident would not have occurred had the pilot of 6160L been further below the undercast than he was, consistent with not only cloud clearance, but also with the chart depicted Warning, poorly located/depicted as it may have been. Coincidentally, the Cessna Cardinal pilot had descended to 2000’ MSL only due to cloud clearance requirements; he was unaware of the airspace warning and would have maintained 2500’ MSL had there been no clouds. Would this have guaranteed there to be no collision? There are no guarantees, however it would’ve given time for either the pilot of 6160L to see and avoid the KC-135A, or for the Luke local controllers to see and issue a traffic warning to the crew or Copper 5. It is possible, though it is also speculation, that at worst, there would’ve been a near-miss, vice a collision. For its part, there is nothing the KC-135A crew could’ve done to mitigate this accident, as they were IMC and never saw the traffic reported to them (the Cessna Cardinal), and never had a chance to see the traffic not reported to them (6160L), in order to take any kind of evasive action. This accident stresses the importance of cloud clearance regulations and the adherence to them when VFR, as cruising Unaware and Unafraid in the Undercast, can truly be a recipe for disaster.


The above is not intended to be an undue criticism of the person or persons involved in the incident described. Instead, the analysis presented is intended to further the cause of flight safety and help to reduce accidents and incidents by educating pilots through the sacrifices of others in our profession.

HI-TACAN 3L IAP, KLUF (current, not 1982)

(Photos courtesy of G. Underhill)

KC-135A 57-1489 vertical stabilizer; KC-135A main wreckage; KC-135A rudder pedal in mud; N6160L fuselage.

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Nice writeup as always Mike. I spent a fair amount of time flying around that area back in 2004 and 2005 when I was flight instructing out there. The combination of rapid changes in terrain elevation and the common broken layer of low laying clouds tended to limit the number of altitudes that were available for flight. Throw in a large number of MTRs, MOAs, restricted areas, STARS into PHX and the very large number of training aircraft, both civilian and military, and the possibility of a close call, even when following all the regulations and best practices, was very high.
Why was the Air Force so slow to implement TCAS in their aircraft? Wouldn't the collision off the Coast of Africa in 1997 (I think) would have been prevented if TCAS was installed?
Why was the Air Force so slow to implement TCAS in their aircraft? Wouldn't the collision off the Coast of Africa in 1997 (I think) would have been prevented if TCAS was installed?

DOD has always been seemingly behind the times in implementing some items that may already be seen in the civilian world, notable non-combat items. I've seen Cessna 210s with better avonics than the A-10s I flew. However the instrumentation and bombing system for the F-117 was state of the art.

The midair between the C-141 and the TU-154 off Africa could very well have been prevented had TCAS been onboard; and that accident was the one that caused TCAS to be implemented pretty quick.