When Routine Ops become Not So Routine

MikeD

Administrator
Staff member
Time will erase the painful memory of the mistake you just made. So will the next mistake......

24 June 1985
Galena Air Force Station (PAGA)
Galena, Alaska

McDonnell Douglas F-15A Eagle, 74-0087
43rd Tactical Fighter Squadron (TFS)/21st Tactical Fighter Wing (TFW)
Alaskan Air Command, USAF
1 Fatal


For this 10th installment of MikeDs accident analyses, I'll analyze how non-routine operations performed in a routine way, as well how the major impacts from a minor oversight, can end up with completely unintended results.

One of the unique and fun things about aviation is when pilots get to bring the world of aviation to non-pilots. This can be accomplished from the most benign, such as an airline crew talking to passengers about flying prior to or after a flight, or bringing them into the cockpit; to the more extreme, such as when aerial demonstration teams like the USAF Thunderbirds, US Navy Blue Angels, or the Canadian Snowbirds, among others, wow crowds with their aerial demonstrations; and everything inbetween. These demonstrations are well choreographed, planned and scripted. Such demonstrations are true crowd pleasers especially for people who support and maintain flying operations, the people who make the whole thing possible. Things like incentive rides and mini-airshows or flybys can be a great morale boost to those who work long and hard to make it possible for these aircraft to get into the air. Many of these smaller-scale short demonstrations are generally impromptu and on the fly, with less preplanning. That less preplanning creates a challenge in and of itself and increases the risk factor somewhat, the degree of that risk increase dependant on any number of factors, from the most minor to the major. The key is to be able to mitigate these factors as much as possible, thus not allowing Mr Murphy to make himself the proverbial uninvited guest at the party. Failure to do so will usually end in a situation such was seen on a cool Monday afternoon, 24 June 1985, at Galena AFS Alaska.

In 1985, the Cold War was still very much in effect against the Soviet Union and other member nations of the Warsaw Pact. The state of Alaska was seen as a strategic defensive position protecting both Canada and the United States from aggression from the eastern side of the Soviet Union and across the Bering Strait. As such, the US Air Force's Alaskan Air Command had a few squadrons of fighter aircraft, among other types, to help defend the Alaska penninsula from any Soviet air threat, namely bombers which consistently flew along the Alaskan coast in international waters, testing US air defenses. Very often, USAF fighters would scramble from a number of locations to intercept and escort these Soviet bombers, insuring they had no ill intentions. This game of cat and mouse had been going on for a long time, and today, 24 June, was no different.

To defend the Alaska pennisula, the Alaskan Air Command (AAC) had a few squadrons of F-15A Eagles based primarily out of Elmendorf AFB (ICAO: PAED) near Anchorage. Generally, 4 x F-15As sat air defense alert at a ready posture. In order to shorten response time to intercept an intruder aircraft coming from the west, AAC had two additional Forward Operating Location (FOL) alert sites at King Salmon Air Force Station (ICAO: PAKN) on the southwestern portion of the Alaskan pennisula, and Galena Air Force Station (ICAO: PAGA) on the west-central half of the state bordering the Yukon River. Each FOL had a detachment of 4 x F-15As and associated maintenance personnel who rotated back and forth from the FOLs and Elmendorf AFB on a regular schedule.

On this day, F-15A 74-0087 was sitting air defense alert at King Salmon AFS. The pilot of 087 was a 24yr old O-2 (1st Lieutenant) first-assignment wingman with approximately 515TT and 315TT in the F-15A aircraft. He was assigned as the wingman of a 2-ship section of Eagles there at the alert hangar. At this time, the home-station at Elmendorf was undergoing an Operational Readiness Inspection (ORI) whereby the base was being inspected and graded as to how it executes its wartime mission. Late in the morning, the alert klaxon horn sounded in the alert hangar facility at the King Salmon forward location, signaling a scramble launch. Not knowing whether this was a practice launch or the real thing against a real target, the Eagle crews treated the sitation as being real like they always do, moved to get mounted-up, engines started, taxied and airborne within minutes. The pilot of 087 did just this, following his lead jet out the alert hangars in minutes and launching with a full live-load of 4 x AIM-7F/M Sparrow medium-range radar-guided air-air missles, 4 x AIM-9L/M Sidewinder short-range air-air IR missiles, a full load of 20mm cannon, and 3 x 600 gallon external drop tanks, one under each wing and one under the centerline station.

Following launch and contact with the Ground Control Intercept (GCI) radar station, the flight was informed that this was a practice intercept launch and was vectored to a notional air threat for a simulated intercept. Following completion of this, the flight was cleared to Return to Base (RTB) to King Salmon. During the RTB, the pilot of 087 got an Environmental Control System (ECS) warning indication in his cockpit. Knowing the potential seriousness of an ECS malfunction, the flight lead declared an emergency with ATC, gave the navigation lead to the pilot of 087, and assumed a chase position on his wingmans jet. The decision was made to divert to Galena AFS, it being the closest field as well as the most suitable, with both the runway as well as coincidentally the maintenence availability from the alert detachment located there. Appropriate emergency checklists were completed, and descent, approach, and landing were uneventful; the pilot of 087 making a full stop, while the flight lead made a low approach and RTBd to King Salmon AFS.

On the ground at Galena, maintenance began inspection and repairs to 087, and if repairs were completed with sufficient daylight remaining, then 087 could RTB to home station at Elmendorf. Within a few hours, the appropriate repairs were made to 087, the aircraft was refueled, and the pilot was cleared from home station to return to Elmendorf the same day. As the aircraft forms were being completed, the pilot notified the alert detachment Supervisor of Flying (SOF...an O-3 Captain) of his intention to make a low pass flyby after takeoff and prior to departing to Elmendorf. These flybys were a regular occurrance and served as a morale boost for the maintainence personnel at the FOLs who were often working in very cold climate conditions to keep the aircraft flying. Forms complete, the pilot of 087 mounted up and engine start and taxi were uneventful. As RW 7 was the active at this time, and the USAF alert ramp and hangar was located at the western half of the airfield on the north side, the pilot of 087 requested a 180 degree turn after takeoff for an opposite direction low-pass down RW 25 prior to departing the Airport Traffic Area (ATA). With the request granted by tower, the pilot of 087 made an uneventful normal takeoff from RW 7. At about a mile from the RW 7 departure end, the pilot made a series of 90 degree turns to reverse course back inbound for the low-pass down RW 25. Completing the course reversal, the pilot descended and crossed the approach end of RW 25 inbound at an estimated 100-200AGL and 550-600 knots in afterburner (AB). Passing down RW 25 and about 1000 feet from the departure end and abeam the USAF alert hangar, the pilot executed an abrupt wings-level pull-up and climb, still in AB. The F-15A instantly and violently broke apart, exploded into flames, and crashed just off the departure end of RW 25 into the Yukon River. There was no ejection and the pilot was fatally injured.


Probable Cause:

*Inflight Planning/Decision Making- Improper- Pilot In Command
*Design Stress Limits of Aircraft- Exceeded- Pilot In Command
*Wings- Overload

Secondary Factors:

*Improper Aircraft Warning Systems Operation/Configuration- Pilot In Command
*Wings- Failure, Total
*Wings- Separation

Tertiary Factors:

*Operations Supervision- Improper- Fighter Wing Level
*Operations Supervision- Improper- Local Detachment Level

MikeD says:

This accident highlights a number couple of areas that tie-into the aforementioned discussion of impromptu and short-planned non-routine operations such as aerial demonstrations, and the potential hazards associated with them. Two of the primary areas to focus on as it relates to this accident, are:

1. The planning of the Flyby itself on this day.
2. The execution of the Flyby by the pilot of 087

Planning of the Flyby: As noted in the description of the accident sequence, high-speed low-pass flybys and other mild aerial demonstrations were a fairly common occurrance at the FOL alert sites, and had been for some time. Seen as a morale boost for the support personnel at these FOLs, who often spent weeks away from family and home in these small locations that had not much to do other than work, aerial demonstrations such as flybys really helped provide a sense of camraderie and teamwork. This allowed maintenance and support personnel to take pride of ownership that the hard work they performed daily and under sometimes grueling climate conditions, could be seen in its end-state. These aerial demonstrations were both known about and condoned as the intended morale booster they were by the home-base 21st TFW leadership. The problem was, that these aerial demonstrations violated several USAF-level and AAC-level regulations in-place, as well as the 350 KCAS restriction regulated in then-Air Force Regulation (AFR) 60-16. As there had been no incidents or accidents resulting from these mild demonstrations, it's surmised that the regulatory violations were overlooked by the leadership. On a more local supervisory level, the pilot of 087 advised the alert detachment SOF of his plan for the flyby post-departure. This was done more as a courtesy to the SOF, as the local alert-det SOF really wasn't in charge of the home-station based pilot of 087, and was only responsible for the alert detachment based jets themselves. As there had been no prior problems with flybys such as this one, the more experienced SOF, both rank-wise as well as quaifications-wise, saw no issue with its performance or execution, and joined the maintenance folks and pilots of the alert det on the ramp to witness it.

Execution of the flyby: If these high-speed low-pass flybys and other aerial demonstrations had become routine by pilots of the 21st TFW, why had this one suffered the tragic ending it did on this day? Investigation of the wreckage of 74-0087 revealed a very minor preflight oversight, one that during any routine operations wouldn't have likely been noticed, but with a non-routine maneuver such that was being performed today, this one item would make the difference between success and failure. Proper operation of this system, known as the Overload Warning System (OWS), combined with how this system is commonly used by F-15 pilots, is key.

OWS System Operation: In the F-15 Eagle, there is a system known as the Overload Warning System (OWS). The OWS is a system that takes inputs from various sources on the aircraft and determines, based off of aircraft weight/configuration, when to set off a warning tone in the pilot's helmet that tells the pilot he's approaching a G-overload condition. One of the places the OWS gets information from is the Armament Control Panel (ACP). In the A-model F-15, the aircraft cannot automatically sense what is physically hanging off of the aircraft or attached to the underwing hardpoints. The only way the aircraft knows what it has onboard is by what the pilot manually sets into the ACP based on each weapons station. It was discovered that post-accident, the pilot of 087 had set his ACP incorrectly. The missiles onboard were properly set into the ACP, but the three 600 gallon external drop tanks, one under each wing and one under the centerline, were not. This caused the OWS to have a mismatch, as it was being told by the fuel totalizer that there was far more fuel onboard than what the ACP was showing the aircraft was capable of. More than likely, this would've caused the OWS to shut down, with no warning that it was shut down. It's assumed that this incorrect ACP setting was the same way prior to the first launch at Elmendorf AFB, but there was no maneuvering having been performed during the first sortie where the incorrect setting would've been noticed and corrected. It wasn't until after takeoff on the second sortie, and where the pilot operation of the OWS system comes into play, where there would be the tiny window of opportunity to catch this minor error, it having already been missed on the ground.

Pilot use of the OWS: One of the big factors remaining, following the pilot of 087 missing the incorrect setting of the ACP, was how pilots utilize the OWS system. Generally speaking, and with the correct settings, the OWS will provide aural warning tones of an approaching G-overload. While there is also a G-meter in the cockpit, the nature of what air-air aircraft do and their mission, in the times where the pilot will be pulling high Gs, he will likely be heads outside the cockpit, such as in a dogfight. As such, the pilot doesn't have the time or luxury to go inside the cockpit to check the G-meter, even for a second. Consequently, the pilot generally relies on hearing the OWS tones to tell him of impending G-overloads, thus allowing him to manage the aircraft appropriately in order to maintain or reduce Gs, without over-G-ing the aircraft and damaging it. In the case of 087, the pilot was very likely waiting for the OWS tones to sound during his initial abrupt pull-up, and would manage the G-loading from there. With the mismatch in the OWS due to the improper ACP setting and subsequent shutdown of the OWS system, the pilot was listening for warning tones that would never come. At best, he would've had a possible second or so to check the G-meter were he heads-inside the cockpit, but more than likely he was not. With no warning of the rapid G onset and approach to structural overload, the point of no return had been reached, and there was no turning back.

MikeDs Final Thoughts: Regulations aside in this accident, when one desires to undertake non-routine operations such that were taken here, or operations that have become routine but aren't often practiced, one has to take great care that they take the time to properly plan and execute. In this accident, a fairly simple endeavor had fatal consequences due to a very minor oversight that had very major implications. In these situations, it's imperitive to insure that the time is taken to use experience, procedures, and your Situational Awareness (SA) bag of tricks to give every chance for a successful outcome. And remember, slower is always faster in these situations, in terms of giving yourself time to catch little problems before they become big ones. If you don't have the time to do that, then reconsider performing the operation at all. When non-routine operations start getting even the smallest degree of overlooked items or even complacency, that's when Mr Murphy begins looking for ways to make himself your uninvited guest to your party. Don't make the job easy for him. Routine Ops shouldn't have to become Not So Routine.


MikeD


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.

Photo: F-15A Eagles of the 43rd TFS/21st TFW, sister aircraft to 74-0087, in-flight in Air Defense configuration (Photo: USAF)
 

Attachments

  • 015.jpg
    015.jpg
    352.1 KB · Views: 1,578
Last edited:
Thanks for taking the time for another thorough write up.

Great read, Mike.
 
the pilot was very likely waiting for the OWS tones to sound during his initial abrupt pull-up, and would manage the G-loading from there.

Can't speak for the A model, but in the E model we apply G initially with respect to stick position at known airspeeds, then wait to see what the OWS tells us.

The F-15 also has what we call a "thumbprint" in the G envelope -- this is where at higher speeds (above 450 IIRC) where the max G available starts to decrease and that "known stick position" is no longer valid. So, while the known stick position works extremely well below 450, it can lead to an over-G depending on how far into the thumbprint you are.

So, I'd have to guess here that the pilot, even without the external tanks, may have been pulling to that known stick position, which wouldn't have been valid anyway at 600 knots. Add the bags into it, and you have the makings of a pretty spectacular departure low pass.

You should do a writeup on another spectacular departure low pass, the T-6 crash at Savannah, GA, back in '04 or '05. What happened on that one reads like a laundry list of what not to do.
 
pull-up and climb, still in AB. The F-15A instantly and violently broke apart,

Military jets are designed with ULF 1.5 LLF, right? I guess at speeds like this it doesn't much matter, but I'm still curious.

Thanks again, another great write up.


Hacker: It is still manual in the E model? In other words, the OWS doesn't automatically prevent you from over Ging like the fly by wire 16s? (Unless I'm confused on the 16s as well.)
 
Hacker: It is still manual in the E model? In other words, the OWS doesn't automatically prevent you from over Ging like the fly by wire 16s? (Unless I'm confused on the 16s as well.)

Actually, both aircraft can be Over-G'd.

In the F-16, you're right that the flight control computer tries to only provide the optimum performance and limits AOA and G to stay in the flight envelope. You can, however, over G. I don't know the details of how, but that's what my F-16 bretheren tell me.

In the F-15E, there is a flight control computer, but it does not limit AOA or G like in the F-16. The E model flight control system consists of two "layered" systems that are working simultaneous to each other: The base system is a "hydromechanical" system -- an old school stick-to-pushrods-to hydraulic actuators system. Operating on top of that is the "Control Augmentation System", which is the fly-by-wire portion. This system only controls the rudders and stabs, and takes inputs from the stick/rudder pedals, a stick-grip force sensor (like in the F-16), and the air data computer, and runs the unputs through a flight control computer brain that optomizes the flight control responses.

So, most of the time the jet is flying using inputs from the CAS system, but when you need to have the control surfaces command something more (in terms of G or AOA), the hydromechanical system allows those inputs to happen.

Bottom line: you can over-G the hell out of the Strike Eagle and the computer won't stop it!
 
Back
Top