The Story about PWA Flight 314

On 11 February 1978, Pacific Western Airlines Flight 314, a Boeing 737-200 crashed at Cranbrook/Canadian Rockies International Airport, near Cranbook, British Columbia, Canada, killing 42 of the 49 people on board.

Boeing 737-200 Cockpit (Night)

The scheduled flight from Edmonton International Airport to Castlegar Airport via Calgary, Alberta and Cranbrook, British Columbia crashed after its thrust reversers did not fully stow following an aborted landing to avoid a snow plow on the runway. Calgary air traffic control was considerably in error in its calculation of the Cranbrook arrival time and the flight crew did not report while passing a beacon on final approach.

The investigation was conducted by the Aviation Safety Investigation Division of Transport Canada and audited by the Aircraft Accident Review Board.

Cranbook is an uncontrolled airport, but it is in controlled airspace. Therefore there was no legal requirement to get permission for landing after clearance for the approach was given. At the time of accident, it was snowing with visibility of 3/4-mile. Snowplow operator was informed that estimated time of Flight 314 arrival would be 2000Z. Flight 314 touched down at 1955Z, approximately 800 feet from the runway threshold. Reverse thrust was selected. Immediately, reverse thrust was cancelled and a go-around was performed. The aircraft was airborne prior to 2000 feet, and flew over the snowplow at 50 to 70 feet of altitude.

Left thrust reverse doors deployed. The aircraft climbed to 300–400 feet above the airfield, banked steeply to the left, and side-slipped into the ground. At impact, the left thrust reverser was fully deployed and the right thrust reverser was nearly stowed. Left engine was near idle power, right engine was developing power, and there was full right rudder and aileron. Gear was down and flaps were at cca 20 degrees.

Open Thrust Reverser B-737-200

Boeing simulations showed that aircraft was controllable with one engine at idle reverse and the other at full forward thrust in gear up, flaps 15 configuration. With flaps 25 and gear down, it was not possible to maintain level flight.

Closed Thrust Reverser Boeing 737-200

The go-around would have been successful if the left engine thrust reverse doors had not been deployed.

Pacific Western flight 314 was a scheduled service from Edmonton, AB (YEG) to Castlegar Airport, BC (YCG) with stops at Calgary, AB (YYC) and Cranbrook (YXC). The flight departed Calgary at 12:32 in the afternoon. The airplane climbed to FL200 which was reached at 12:38. Calgary ATC then reported to the Cranbrook Aeradio station that flight 314 was underway with an ETA of 13:05. At Cranbrook it was snowing with the visibility reported as 3/4 of a mile, and a radio equipped snow removal vehicle was sweeping the runway.

The Aeradio operator at Cranbrook alerted the driver of the vehicle about the incoming aircraft and gave him the ETA of 13:05; they both expected the flight would report by the “Skookum Beacon” on a straight-in approach to runway 16, thus giving the vehicle operator about seven minutes to get off the runway. At 12:46, while descending out of FL180, flight 314 contacted Cranbrook Aeradio.

One minute later the crew were advised that snow removal was in progress. No further transmissions were received from the flight by Aeradio. The aircraft passed the Skookum beacon inbound on a straight-in instrument approach, and flew the ILS for runway 16 to touchdown. The aircraft touched down at 12:55 some 800 feet from the threshold and reverse thrust was selected. Suddenly the crew noticed a snow plough on the runway. A go-around was initiated immediately. However one of the thrust-reversers didn’t fully re-stow because hydraulic power was automatically cut off at lift-off.

The aircraft became airborne prior to the 2000 foot mark, and flew down the runway at a height of 50 to 70 feet, flying over the snow plough. The left engine thrust reverser doors then deployed and the crew rapidly selected the flaps up from 40deg to 15deg. The airplane climbed to 300-400 feet, banked steeply to the left, lost height and side-slipped into the ground to the left of the runway. The aircraft broke up and caught fire.

CONCLUSIONS (FINDINGS):
1. The estimated time of arrival of the aircraft at Cranbrook, calculated by Calgary ATC, and used by Aeradio for advisory purposes was considerably in error and resulted in a traffic conftict between the arriving aircraft and a vehicle working on the runway.

2. The flight crew did not report by the Skookum beacon on final approach, as was the normal practice at Cranbrook, thereby allowing the incorrect ETA to remain undetected.

3. Regulatory provisions concerning mandatory pilot position reporting during instrument approaches were inadequate.

4. The interfaces between the organizations providing Air Traffic Services, Telecommunications (Aeradio) and Airports Services were not well enough developed to provide a reliable fail-safe flight information service.

5. The pilots lost control of the aircraft consequent upon the left engine thrust reverser deploying in flight when the aircraft was at low speed, and in a high drag configuration.

6. The FAA design standards under which the Boeing 737 was constructed did not adequatety provide for the possibility of an aborted landing after touchdown and thrust reverser initiation.

7. The lack of a suitable national system of incident reporting, investigation, and follow-up corrective action allowed operational problems to remain uncorrected.

8. Rescue efforts at the accident scene were hampered due to lack of a fire fighting vehicle capable of negotiating deep snow and shortage of trained rescue personnel.

Final Words

A – Cranbrook Aeradio
D – Calgary Departure
E – Calgary En route
G – Snow Sweeper
L – Aeradio Landline
PW314 – Pacific Western Flight 314
T – Calgary Tower

• 12.18 PW314: Calgary Clearance Delivery it’s Pacific Westerns three fourteen.
• D: Three fourteen to the Cranbrook Airport centre stored flight level two zero zero. Depart runway one six, runway heading until through ten thousand, turn right squawk one three zero zero.
• PW314: OK, three fourteen, the Cranbrook Airport, centre stored, flight level two zero zero runway one six to ten thousand before turning right squawking thirteen.
• D: That’s correct three one four, time one nine one nine and advise push back this frequency.
• 12.29 PW314: Three fourteen’s ready in sequence.
• T: Three fourteen to position and hold sixteen.
• PW314: Three fourteen.
• 12.30 T: PW three one four you’re cleared for take-off runway sixteen, departure frequency one nineteen eight when airborne.
• PW314: Three one four roger.
• 12.31 PW314: Calgary Departure it’s Pacific Western three one four, runway heading out of forty-two hundred.
• D: Three one four is in contact: you can proceed on course.
• PW314: Three one four on course.
• 12.33 L: Cranbrook radio-Calgary.
• L: Cranbrook’s on.
• L: I’ve got an inbound three one four from Calgary at two zero zero five.
• L: Roger, Echo Hotel.
• 12.34:05 A: Are you out there, my friend.
• 12.34:08 G: Yes sir.
• 12.34:09 A: Er – Five past the hour, Terry.
• 12.34:11 G: OK. What’s the time now, Ernie?
• 12.34:13 A: Er – Half an hour from now. Thirty just coming up to thirty five.
• 12.34:16 G: OK. Thank you. Everything’s working good out here.
• 12.34:20 A: That’s good.
• 12.34:23 G: Can’t see you from here, so I don’t know whether you’re good looking or not.
• 12.34:27 A: Oh – take my word for it – I’m good looking.
• 12.34:29 G : 0.K.
• 12.36 D: PW three one four can call enroute one thirty three three, good day.
• PW314: Calgary Enroute, it’s Pacific Western three one four on one thirty three three out of sixteen thousand for two zero zero.
• E: Three one four’s radar.
• 12.38 PW314: Three fourteen !s level two zero zero.
• E: Roger three fourteen you can come up on one twenty-five two.
• 12.42 PW314v Calgary, it’s Pacific Western three fourteen request descent.
• E: Three fourteen cleared to the Cranbrook Airport for the approach, the altimeter at Cranbrook two nine seven seven, advise leaving one eight oh.
• PW314: OK, cleared to the Cranbrook Airport for an approach, nine seven seven and, ah, will call at one eight.
• 12.43 E: Three fourteen.
• 12.44 PW314: Three fourteen’s out of one eight thousand.
• E: Roger advise time down this frequency.
• 12.46 PW314: Cranbrook Radio. Pacific Western three one four-er-your frequency.
• A: Three one four, Cranbrook, go ahead.
• PW314: Yes, sir. We have the approach. You can go ahead with your numbers.
• A: OK – I’ll give you the numbers – the wind at one five zero degrees magnetic at six Cranbrook altimeter two nine – two nine seven six and there’s no reported traffic.
• 12.47 PW314: OK. We check-two nine seven six.
• A: And three one four. The-er-sweeper on the runway-er-has been for some time trying to keep the snow back for you. I’ll let you know what it’s like as soon as I get a progress from him. And the visibility – not much change in the weather – maybe visibility about three quarters of a mile in snow.
• PW314: Three fourteen checks.
• 12.55: PW314 We’re gonna crash
• G: Where the hell did he come from?
• A: I don’t know Terry, but he sure didn’t call after his first call.
• L: Cranbrook radio, Calgary.
• L: Cranbrook.
• L: I’ve got an inbound for you.
• L: Standby a second please, I got an emergency.
• L : Oh. OK.
• 20.04 L: Cranbrook Radio, Calgary, are you still busy?
• L: Aoah, OK go ahead now Calgary.
• L: OK, first off, where’s PW three thirty, three fourteen now, have you any idea
• L: Yeah, he’s the emergency he’s crashed and is burning off the end of the runway.

Figure of Thrust Lever

In Memory of all who perished in this crash RIP.