Date: 201303
Local time of day: 1201-1800
Location: BWI.Airport, MD
Flight conditions: IMC
Weather elements / visibility: 2.5
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B BWI
ATC / advisory: Tower BWI
Aircraft component: ILS/VOR
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Human factors: Communication Breakdown; Distraction
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: We were being vectored for the ILS 33L at BWI. I was the pilot flying and the Captain was the pilot not flying. After I was established on the Localizer at 2;000 FT and cleared for the approach; I observed that I had red flags on the glide slope. And; I had no glide slope indications. I told the Captain I had no glide slope. I did not hear his response. The Tower frequency was busy and; with the continuous RF radio noise in my headset; what he said I did not hear. I again said I had no glide slope indication and; as I was approaching GRAFE; the final approach fix; I said I was going to revert to Localizer only minimums and complete the approach as the Localizer 33L approach. Past GRAFE I started a descent to the Localizer minimums. The Tower called and said they had a low altitude alert on us. The Captain told them we were at 600 FT MSL. At that point; the Captain said that he was taking control of the aircraft. I said; 'You have the controls.' The Captain completed the approach and landing using his instruments as well as the glide slope; which was working on his side. I was not aware that he had a glide slope indication until that point. The landing and completion of the flight was uneventful. When I noted my loss of glide slope; I should have checked the Captain's glide slope to see if he had any glide slope indications. If I had known that he had a glide slope indication; I would have transferred control of the aircraft to the Captain at that point. There was a breakdown in communications at that point. A contributing factor was the constant RF noise in my headset from the radios. I had mentioned it several times during our two legs on the aircraft. It was loud enough to make hearing ATC communications difficult several times. If I was to experience this event again; with the same conditions; a go-around/missed approach would probably be the best course of action. Without the assurance that both pilots were absolutely seeing the same thing and verbally agreeing to the next course of action; a go-around would be a good course of action.


Second narrative: As we intercepted the final approach course and glide slope; the First Officer's glide slope flag came into view. We had started the descent and stopped at 620 FT MSL as per the step-down altitude. Tower advised us of an altitude alert and we advised we were at 620 FT (the step-down altitude for the Localizer approach.) The field came into view prior to the missed approach point; but we felt it would be best if I landed the aircraft; which I did. I probably should have taken over the approach sooner since my ILS system was normal.


Synopsis: An air carrier First Officer's ILS glide slope failed during final approach but the Captain did not hear his failure declaration but after ATC called low altitude alert the Captain assumed control and landed.